CN105316590A - High-tenacity boron-containing high-speed steel and preparation method thereof - Google Patents

Abstract

The invention discloses high-tenacity boron-containing high-speed steel and a preparation method thereof. The high-tenacity boron-containing high-speed steel comprises, by mass, 0.30%-0.6% of C, 3.5%-5.0% of Cr, 0.4%-1.15% of Si, 3.4%-5.2% of Mn, 0.8%-2.5% of B, 0.9%-2.8% of Mo, 1.0%-3.2% of W, 0.5%-1.5% of V, 0.6%-1.8% of Cu, 0.5%-1.2% of Ti, 0.05%-0.20% of Ca, 0.05%-0.25% of Ce, 0.05%-0.2% of Y, 0.02%-0.18% of N, 0.05%-0.3% of Nb, 0.12%-0.25% of Mg, 0.06%-0.15% of Ba, 0.04%-0.13% of K, less than 0.03% of S, less than 0.04% of P, and the balance Fe. The above components are smelted to the temperature of 1560 DEG C to 1620 DEG C by using an intermediate frequency furnace, after ferrovanadium in 60 meshes to 100 meshes, potassium oxide, silicon-calcium-barium alloy, ferrochromium containing nitrogen, BC, BN, B2O3, Si3N4 and modifying element rear earth Ce and Y are proportioned together according to the mass percent, the mixture is rolled into metal cored wires of which the diameter is from 8 mm to 15 mm, the metal cored wires, serving as boron supplying agent, are added into molten steel, then boron is added, modifying inoculation is conducted, and the molten steel is poured into a casting. Heat preservation is conducted on the casting for 2 h to 4 h at the temperature of 920 DEG C to 1150 DEG C, and then the casting is subjected to air cooling to the room temperature. The high-tenacity boron-containing high-speed steel has the advantages of being good in strength, hardness, tenacity, thermal-fatigue resistance and abrasion resistance and low in production cost.

Description

High tenacity boracic high-speed steel and preparation method thereof

Technical field

The invention belongs to steel material technical field, relate to a kind of casting wear-resistant die steel and preparation method thereof, particularly a kind of high tenacity boracic high-speed steel and preparation method thereof.

Background technology

The requirement of development to material of modern science and technology is more and more higher, the industrial sector ubiquities such as wearing and tearing are mines, metallurgy, machinery, electric power, coal, oil, building materials, traffic also become the major reason causing structure deteriorate or material failure and energy consumption, also be one of main failure mode of mechanical component three kinds, research and development a new generation high-abrasive material, reduce galling, national economy is had great importance.The metal wear resistant material of current widespread use mainly contains steel alloy and casting ferrio wear-resistant material, the former good toughness, but there is the deficiency that hardness is low and wear no resistance.Ferrio wear-resistant material can be divided into two large classes, a class be in tissue containing in large quantities, thickly, high rigidity ground hard phase (>=5%vol.); Another kind of is do not have in tissue or only contain marginally hard phase.Because the wear resistance of hard phase is higher than matrix, so hard phase becomes the wear-resisting skeleton of high-abrasive material naturally.Traditional white cast iron is the Typical Representative of this class high-abrasive material.In white cast iron, containing the M of the 10%vol. that has an appointment in tissue ₃c type or M ₇c type carbide.Because M ₃c type or M ₇c type carbide has high rigidity, and thus, white cast iron has high-wearing feature.In ferrio wear-resistant material, what find at present can mainly contain two large classes as the hard phase of wear-resisting skeleton, and a class is carbide; Another kind of is boride.At present, people to using carbide as the ferrio wear-resistant material of wear-resisting skeleton study more, and for using the boride with more high rigidity as the ferrio wear-resistant material of wear-resisting skeleton study little.Because white cast iron has high rigidity and high-wearing feature, thus at present still such material is used in a large number in metal wear resistant material field, but it is large to there is fragility in such material, easily peels off the deficiency even ftractureed, thus cannot meet the requirement of development of modern industry to high-performance abrasion-proof material in using.Therefore, Development and Production technique is simple, low production cost, intensity and toughness are high, hardening capacity and the good New Generation Steel high-abrasive material of hardenability, and under abrasive wear operating mode, replace now widely used common high-abrasive material, tool is of great significance undoubtedly.

For improving the abrasion resistance of metal wear resistant material, meeting application requiring, in recent years, having carried out large quantifier elimination both at home and abroad, have developed a large amount of novel high-performance high-abrasive materials.Chinese invention patent CN1039267 discloses a kind of composition and preparation technology thereof of antiwear high-chromium cast iron, the chemical composition (by weight percentage) of this material is: 2.9 ~ 3.2%C, 0.4 ~ 0.8%Si, 0.4 ~ 1.0%Mn, 1.2 ~ 2.0%Mo, 18.0 ~ 20.0%Cr, 4.0 ~ 5.0%V, 0.8 ~ 1.2%Cu, 0.05 ~ 0.5%RE, P < 0.08%, S < 0.05%, all the other are iron.This antiwear high-chromium cast iron, compared with common high-abrasive material, has wear-resistant, good mechanical property, and thermal treatment process is simple, low power consumption and other advantages, is suitable for the wear-resisting spare part making Working environment harshness.But containing the more alloying element such as vanadium, molybdenum in this kind of antifriction cast iron, production cost is high, and easy to crack when also there is high-temperature heat treatment, the fragility of material is large, easily peels off the even deficiency such as cracking in using.In order to improve the toughness of high-chromium white cast iron, Chinese invention patent CN1115339 discloses Cr series white cast iron compound inoculant, while this nucleating agent is selected and has been solidified C, Cr, Fe element of inoculation(effect) to Cr series white cast iron, by adding Si, Mg, RE alloying element, to change second-phase form and distribution, play the metamorphism to metal melt, technique have employed the technological line breeding and be combined with metamorphic facies.Adopt this invention that the ballistic work of Cr series white cast iron can be made to reach 4.5J, make impelling strength improve 60%, fracture toughness property reaches 32MPa.m ^1/2, improve 30%, tensile strength reaches 668MPa.But the fragility of this material is still comparatively large, and use under heavy duty, gouging abrasion operating mode, safe reliability is lower.

Peng Shi China richness produces element, and total storage accounts for the 5th, the world.Large quantity research shows, adds appropriate boron in steel, by regulating Boron contents and carbon content in alloy can realize the control to boride percent by volume and base carbon, makes material have excellent wear resistance and obdurability.In white cast iron, add all right refining eutectic carbide of trace B, improve form and the distribution of carbide, improve white cast iron mechanical property.Verified in engineer applied, boron adds in structure iron can replace part or all nickel, chromium, manganese, molybdenum etc., and replace 40Cr steel with boron steel in the automotive industry, its work-ing life is not less than chromium steel.Exploitation take boron as the metal wear resistant material of main alloy element, make it have good hardenability and hardening capacity, expensive alloying elements add-on is few, low production cost, and melting technology is simple, plasticity is good, pollution-free, adopt metal melt purification and Metamorphism treatment technique simultaneously, improve boron-containing alloy materials microstructure form, make it have good obdurability and wear resistance, will be with a wide range of applications in high-abrasive material field.Chinese invention patent CN1624180 discloses a kind of high boron foundry iron base anti-wear alloy and heat treating method thereof for this reason, the main chemical compositions (% by weight) of this high boron foundry iron base anti-wear alloy is: 0.15 ~ 0.70%C, 0.3 ~ 1.9%B, 0.4 ~ 0.8%Si, 0.6 ~ 1.3%Mn, 0.3 ~ 0.80%Cr, 0.05 ~ 0.25%Ce, 0.02 ~ 0.10%La, 0.005 ~ 0.018%Ca, 0.04 ~ 0.18%K, 0.08 ~ 0.25%Al, P < 0.04%, S < 0.04%, all the other are Fe.This alloy after heat treatment can obtain the complex tissue that lath martensite adds high rigidity boride composition, make material have good over-all properties, but boride is continuous net-shaped distribution, makes the fragility of material larger.For improving high boron alloy toughness, carry out large quantifier elimination both at home and abroad.Chinese invention patent CN1804091 discloses the toughening method of casting high-boron wear-resistant alloy, the method is: 0.30 ~ 0.35%C, 1.0 ~ 1.5%B, 0.6 ~ 0.8%Si, 0.8 ~ 1.0%Mn, P < 0.04%, S < 0.04%, all the other are Fe, Ti and inevitable impurity element, and wherein Ti is brought into by alterant ferrotianium.Its toughening method is: first by molten steel melting and with after aluminium deoxidation, add alterant ferro-titanium and carry out Metamorphism treatment, pour into a mould after change is skimmed clearly, malleableize thermal treatment is carried out after casting complete, malleableize thermal treatment temp is 1020 DEG C ~ 1050 DEG C, soaking time is 2 ~ 3 hours, then carries out quenching or normalizing, last tempering: alterant ferro-titanium consumption is 0.75 ~ 1.0% of casting high-boron wear-resistant alloy.The eutectic boride of the sand mold casting high-boron wear-resistant alloy after patent in isolated shape distribution in the base.Because boride is not become particulate state by this technique, be only large block distribution, the fragility that therefore still there is material is large, and toughness is not too high, is only 12.5J, cannot meet the safe handling under heavy duty, gouging abrasion operating mode.

USSR (Union of Soviet Socialist Republics) patent No. SUl, 447,926 disclosed a kind of " high strength and high impact toughness height boron alloy manufacture method ", the chemical composition of this high boron alloy is: 0.2 ~ 0.50%C, 2.1 ~ 3.5%B, 0.15 ~ 0.6%Si, 0.25 ~ 0.80%Mn, 0.2 ~ 0.80%Sb, containing more antimony in this alloy composition, will significantly increase the production cost of high boron alloy, and boron-containing quantity is higher, in alloy structure, boride quantity increases, and is unfavorable for the improvement of high boron alloy toughness.

For improving the wear resisting property of rich chromium cast iron, reduce the production cost of rich chromium cast iron, Japanese Patent JP3150334-A, JP93041691-B disclose a kind of boron-containing high-chromium cast iron, its main chemical compositions is: 2.7 ~ 3.5%C, 0.2 ~ 1.0%Si, 0.5 ~ 1.5%Mn, 27 ~ 34%Cr, 0.5 ~ 2.0%Mo, 0.5 ~ 2.0%W ,≤0.1%B, this high boron, high chrome cast iron is after 950 ~ 1100 DEG C of normalizings and 200 ~ 500 DEG C of tempering, hardness reaches more than 62HRC, and shock strength is more than 0.23.Because Boron contents is less, in order to improve hardening capacity, therefore add 0.5 ~ 2.0%Mo in the alloy, and chrome content is higher, adds production cost.

For reducing production cost, improve the performance of rich chromium cast iron, Chinese invention patent CN101260497A discloses boron-containing high-chromium abrasion-proof cast iron and manufacture method thereof, it is characterized in that the chemical composition of boron-containing high-chromium abrasion-proof cast iron is for (% by weight): 2.5 ~ 3.5%C, 15 ~ 28%Cr, 0.5 ~ 1.2%Si, 0.5 ~ 1.2%Mn, 0.15 ~ 0.3%B, 0.008 ~ 0.03%Ca, 0, 03 ~ 0.08%Ba, 0.02 ~ 0.05%Sr, 0.03 ~ 0.08%Al, 0.20 ~ 0.50%Ti, 0.02 ~ 0.06%La, 0.02 ~ 0.06%Ce, P < 0.04%, S < 0.04%, all the other are Fe, and 0.05%≤La+Ce≤0.10%, 6.0≤Cr+C≤8.0.The manufacture method of this boron high-chromium abrasion-proof cast iron is: stove heat fused is put in the mixing of steel scrap, ferrochrome and the pig iron, add after molten iron is melting down ferrosilicon and ferromanganese adjusting component qualified after temperature is risen to 1560 ~ 1600 DEG C, add silicocalcium pre-deoxidation, pre-deoxidation, after 1 ~ 2 minute, adds aluminium final deoxygenation, and final deoxygenation is after 1 ~ 2 minute, add ferrotianium, ferrotianium adds ferro-boron after adding 1 ~ 2 minute, and ferro-boron is come out of the stove after adding 1 ~ 2 minute; Barium silicon alloy, strontium silicon alloy, aluminium, ferrotianium, ferro-boron and mixed rare earth of lanthanum and cerium are crushed to the fritter that granularity is 4 ~ 10mm, after drying through 150 ~ 180 DEG C, be placed in bottom casting ladle, with pouring method in bag, Metamorphism treatment being carried out to molten iron, then the molten iron temperature after Metamorphism treatment being poured into foundry goods at 1420 ~ 1480 DEG C; Poured into a mould foundry goods is carried out normalizing treatment at 980 ~ 1050 DEG C after insulation in 4 ~ 6 hours, then carries out temper at 250 ~ 500 DEG C, tempering insulation time 8 ~ 10 hours, obtained boron-containing high-chromium abrasion-proof cast iron.Compared with the prior art this invention has the following advantages: 1. adopt cheap boron to replace the expensive alloying element such as molybdenum, nickel, improve the hardening capacity of rich chromium cast iron, reduce rich chromium cast iron production cost 30 ~ 50%.2. the element thinning solidification structures such as mixed rare earth of lanthanum and cerium, titanium, calcium, strontium, barium, aluminium are adopted, alleviate element segregation, improve carbide morphology and distribution, improve intensity and the toughness of boron-containing high-chromium abrasion-proof cast iron, wherein tensile strength is more than 580MPa, and impelling strength is greater than 10J/cm ², hardness is greater than 62HRC.3. adopt silicon-Ca-alloy For Deoxidation, aluminium final deoxygenation, adopt titanium to fix nitrogen in iron liquid simultaneously, stablize and improve the rate of the receipts of boron, the rate of the receipts of boron is greater than 92%, improves the rate more than 10% that boron receives, make boron-containing high-chromium cast iron stable than usual way.4. this boron-containing high-chromium cast iron has excellent wear resistance, has met or exceeded containing molybdenum, nickel high-chromium white cast iron level.But this boron-containing high-chromium abrasion-proof cast iron is due to boron-containing quantity little (0.15 ~ 0.3%), and the boride content in alloy is few, makes its wear resisting property still lower; Due to the carbon content in boron-containing high-chromium abrasion-proof cast iron high (2.5 ~ 3.5%C), make its toughness lower, under heavy duty, large impact wear working condition, use its poor safety performance; Owing to adopting more alloy to carry out Metamorphism treatment, cause Metamorphism treatment complex process, cost increases.

Chinese invention patent CN101660097B discloses wear-resisting alloy steel with high boron, high chrome and preparation method thereof, it is characterized in that the chemical composition of wear-resisting alloy steel with high boron, high chrome is for (% by weight): 0.10 ~ 0.5%C, 3 ~ 26%Cr, 0.5 ~ 1.2%Si, 0.5 ~ 1.5%Mn, 0.3 ~ 2.8%B, 0.3-2.6%Cu, 0.2-0.6%Ti, 0.02-0.15%Ca, 0.03-0.25%Ce, 0.02-0.18%N, 0.05 ~ 0.3%Nb, 0.04 ~ 0.09%Al, 0.02 ~ 0.15%Mg, 0.04-0.13%K, S<0.03%, P<0.04%, surplus is Fe and inevitable impurity element.Although what this patent managed the boride of high, the wear resistance of hardness and thermally-stabilised good high-content and high-content has the chromium of high rigidity and the carbide of the chromium hard phase as wear resistant alloy, boride is embedded on the martensitic matrix of high tenacity, acquisition has high-strong toughness, high-wearing feature, the low cost wear-resisting alloy steel with high boron, high chrome of not nickeliferous and molybdenum element.But the obdurability of this material under high impact stresses operating mode is still not enough, thus limit have impact on the application of this material industryization.

Although boron-containing high-chromium cast iron has good wear resisting property, but boron add the increase causing carbide quantity and boride quantity, by causing the toughness of high-chromium cast iron alloy to reduce, if will toughness be improved, needing to add the expensive alloy element such as molybdenum, nickel, production cost is increased.Therefore, although boron-containing high-chromium cast iron is all studied, because its intensity and toughness are resolved, cause it to fail to obtain extensive promotion and application at home and abroad always.

As everyone knows, the key that material does not damage under the effect of huge local load is the matrix with good toughness.For this reason, in recent years, carry out the research and development of austenite rich chromium cast iron both at home and abroad, achieve good effect.A metastable austenite matrix high-abrasive material distinguishing feature in use has work hardening ability exactly.During this kind of material work, austenitic matrix can bear local assault, and produce certain drawing hardening effect, under larger surging force or frictional force effect, there is viscous deformation in the austenite base high-abrasive material top layer be under metastable state, the austenite in inducing materials surface structure, to martensitic transformation, produces strong work hardening phenomenon, material surface is constantly hardened layer by layer, and hardness ratio is increased sharply before using.According to the difference of impact friction energy size, surface hardness about improves HRC (5 ~ 15) individual unit.Simultaneously because boride particle strengthens the obdurability that high-abrasive material heart portion still keeps austenite structure all, the expansion effect of crackle can be suppressed, reduce boride particle and strengthen breaking and peeling off tendency of high-abrasive material, especially the degree reducing boride, carbide fracture and peel off, drastically increases the anti impact wear-proof ability of alloy.Can say, carbide and austenitic duplex are organized in wear process and support mutually, bring out the best in each other.The material with such microstructure can bear severe working conditions.Under suitable working conditions, its resistance to abrasion can meet or exceed the martensite white cast iron of as-heat-treated condition.

Because metastable austenite plastic deformation ability is better, it is also higher with the bonding strength of carbide interface, simultaneously under shock action, owing to producing work hardening, material surface hardness is improved, thus plays support and protect the effect of carbide.And martensitic matrix due to deformability little, opposing crack propagation ability, when object, in martensite surface, wearing and tearing occurs, material surface regional area, by very large stress, very easily makes crack propagation, to firmly crisp boride and carbide destruction very large.Under effect is cut in impact and cutter, as easy as rolling off a log generation fatigue flake and brittle flaking off cause weight loss to increase, and at this moment need the micro-toughness improving material, the mitigation ability increasing stress raisers just can improve wear resistance.Therefore, under gouging abrasion condition, the wear resistance of martensitic matrix material is not so good as the good of austenitic matrix.

But the metastable state of the austenitic matrix that casting alloy is formed, different from the residual austenite of carbon steel, it will have certain relative stability, and top layer is easy to deformation-induced martensitic transformation when frictional wear.Meanwhile, this alloy also has higher impelling strength.

What is more important, when the austenite structure of high-abrasive material is in metastable state, in process of friction and wear, top layer austenitic matrix produces a large amount of dislocation and fault.Dislocation in different slip system is mutually handed over and is cut, tangles, governs and move each other, thus forms dislocation clustering, formation subgrain boundary dislocation wall.And dislocation clustering district and fault district also α martensite and ε martensitic forming core ground just, under frictional stress effect, top layer metastable austenite brings out (α+ε) martensitic transformation in wear process, thus wear surface is to form α martensite, secondary top layer is to form ε martensite, surface hardness is greatly improved, is far longer than the hardness that common austenite work hardening reaches.And form the negative hardness gradient in a centripetal portion from top layer, enhance the anti impact wear-proof ability of alloy.In addition, because the austenitic matrix in alloy is in metastable state, after surperficial induced phase transition martensitic hardening layer grinds off, austenite below continues induced phase transition martensite and produces under frictional stress effect.From energy point of view, top layer metastable austenite is strain induced martensite phase transformation in wear process, must absorb and consume portion of energy.Like this, in the distortional strain energy just causing wearing and tearing to break, some is consumed in this structural transformation, thus fret wear is reduced, and namely material wear ability improves.

Summary of the invention

The object of the invention is to solve deficiency of the prior art, there is provided a kind of high with hardness, wear resistance good, and have high-strong toughness, high boride content there is the chromium of high rigidity and the carbide of the chromium hard phase as wear resistant alloy, boride is embedded on the martensitic matrix of high tenacity, acquisition has high-strong toughness, high-wearing feature, low-cost high-toughness boracic high-speed steel and preparation method thereof.

For achieving the above object, the present invention can be realized by the design of following basic chemical composition and technical scheme:

Chemical composition and the mass percent thereof of a kind of high tenacity boracic high-speed steel provided by the present invention are; 0.30 ~ 0.6%C, 3.5 ~ 5.0%Cr, 0.4 ~ 1.15%Si, 3.4 ~ 5.2%Mn, 0.8 ~ 2.5%B, 0.9 ~ 2.8%Mo, 1.0 ~ 3.2%W, 0.5 ~ 1.5%V, 0.6 ~ 1.8%Cu, 0.5 ~ 1.2%Ti, 0.05 ~ 0.20%Ca, 0.05 ~ 0.25%Ce, 0.05 ~ 0.2%Y, 0.02 ~ 0.18%N, 0.05 ~ 0.3%Nb, 0.12 ~ 0.25%Mg, 0.06 ~ 0.15Ba, 0.04 ~ 0.13%K, S < 0.03%, P < 0.04%, surplus is Fe and inevitable impurity element.

High tenacity boracic high-speed steel provided by the present invention and preparation method thereof, its manufacturing technology steps is:

(1) boron supplying agent and inoculant manufacture:

By vanadium iron, ferrotianium, potassium oxide, calsibar alloy, be broken into 60 ~ 100 object powder, by 60 ~ 100 object BC, BN, B containing nitrogenous ferrochrome, nitrogenous vanadium iron ₂o ₃, Si ₃n ₄according to mass percent 0.8 ~ 2.5%B, 0.5 ~ 1.2%Ti, 0.10 ~ 0.30%V together with alterant element Rare-Earth Ce, Y; 0.05 ~ 0.20%Ca, 0.05 ~ 0.25%Ce, 0.05 ~ 0.2%Y; 0.02 ~ 0.18%N; 0.05 ~ 0.3%Nb, 0.12 ~ 0.25%Mg, 0.06 ~ 0.15Ba; mix after 0.04 ~ 0.13%K proportioning; adopt thickness 0.12 ~ 0.25mm soft steel steel band packaging, be rolled into diameter 8 ~ 15mm metal cored wire, or directly load in Low Carbon Steel Pipe;

(2) smelt

Steel scrap, ferrochrome are melted in electric furnace, after molten steel is melting down, adds copper coin, ferrosilicon, ferromanganese, molybdenum-iron, ferrotungsten, vanadium iron, control carbon content and reach requirement, after stokehold adjusting component is qualified, melt temperature is increased to 1560 ~ 1620 DEG C, adds silicocalcium and carry out pre-deoxidation, add aluminium final deoxygenation;

(3) boron and rotten inoculation is added

Boron supplying agent manufactured by (1) and inoculant metal cored wire are passed through feeding wire machine, join according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or by the boron supplying agent manufactured by (1) and inoculant steel pipe, add to according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or carry out adding boron and rotten inoculation in the molten steel directly adding cast in ladle to;

(4) casting

Treated good molten steel is poured into foundry goods in sand mold or metal mold, or on whizzer, adopt centrifugal composite casting method to pour into skin for high boron, high chrome wear-resisting alloy steel, internal layer is the double metallic composite material of cast iron, cast alloy iron, spheroidal graphite cast iron or low alloy steel, melt cast temperature 1400 ~ 1450 DEG C;

(5) thermal treatment

1. after casting finish, at 700 ~ 780 DEG C of temperature, be incubated 4-6 hour carry out subcritical air quenching, substrate degradation is become the mixture of ferrite and carbide, make its matrix form metastable austenite tissue, and make its hardness be reduced to 30 ~ 35HRC, so that carry out mechanical workout;

2. after casting finish, or machined after, foundry goods or workpiece are heat-treated 920 ~ 1150 DEG C of insulations for 2-4 hour, it is made to harden to form metastable austenite, then air cooling is carried out to room temperature, to form martensitic microstructure in alloy substrate, the hardness of the material after this thermal treatment process process can reach HRC50 ~ 65;

3. the material after thermal treatment is carried out temper at 150 ~ 200 DEG C, tempering insulation time 2-4 hour, with stove air cooling to room temperature, to adjust hardness further;

Described boron supplying agent is industrial BC, B ₂o ₃, BN, wherein BC content is 50 ~ 60%, wherein B ₂o ₃content is 20 ~ 30%, BN content is 10 ~ 20%;

Described B ₂o ₃boron supplying agent is that industrial borax or boric acid are obtained after dehydration, adopts agent rare earth ferrosilicon to be directly reduced to B in molten steel;

Described N source is VN, Si ₃n ₄with containing nitrogenous ferrochrome;

Described inoculant is Rare-Earth Ce, Y, potassium oxide, calsibar alloy.

Beneficial effect

Compared with prior art, tool of the present invention has the following advantages:

1, the present invention is owing to adopting cheap industrial BC, B ₂o ₃, to replace ferro-boron be boron source to BN, the fluctuation of the add-on deviation of boron is little, and the addition of boron-containing alloy when decreasing smelting molten steel, improves the rate of the receipts of boron; Boron is added owing to adopting wire injection procedure or intubate technique; make each tiny boron source particle can obtain adequately protecting of titanium and inoculant, decrease the oxidation of boron in molten steel, the little rate of recovery of loss of boron is high; the rate of recovery of boron is stabilized in more than 93%, reduces cost.

2, high tenacity boracic high-speed steel of the present invention, by adding austenitizing alloying element manganese in the base, it is made to form boracic metastable austenite matrix, formation Cast Austenite tissue, by adopting micro-Metamorphism treatment to make in iron-boron alloy the nodularization of boride group, make in Fe-Cr-B alloy structure original in continuously, the boride M of net distribution ₂b changes that isolated group is spherical to be evenly distributed on matrix into, thus significantly improves the impelling strength of material.Under gouging abrasion condition, austenite structure produces a large amount of dislocation, fault and strain induced martensite phase transformation because of friction deformation, hardness is sharply raised and wear-resistant.And the austenite on secondary top layer is easily deformable, thus slow down the emergence and development of fatigue cracking, the degree especially reducing boride, carbide fracture and peel off.Boride, carbide and austenitic duplex are organized in wear process support mutually, bring out the best in each other, thus make its level reaching high hardness material and maintain the integrated performance index of sufficiently high obdurability and high impact-resistant wear resistance, antiscour corrosive nature, thus realize its industrial applications in HI high impact wear working condition inferior high reliability wearing and tearing field.

3, high tenacity boracic high-speed steel of the present invention replaces the alloys such as expensive nickel owing to adopting cheap boron, production cost is low, comparable rich chromium cast iron reduces production cost 30 ~ 50%, by the Addition ofelements adding molybdenum, nickel, vanadium, tungsten can form carbide, nitride, boride and carbon-boride, form high tenacity boracic high-speed steel, improve the wear resistance of material, make high tenacity boracic high-speed steel of the present invention have good Resisting fractre toughness, thermal fatigue resistance and thermal shock resistance.

4, high tenacity boracic high-speed steel of the present invention is low due to carbon content in matrix, thus has higher cold & heat fatigue resisting, Resisting fractre toughness and thermal shock resistance, can meet the requirement of hotwork operating mode to moulding stock.

5, high tenacity boracic high-speed steel of the present invention is due to containing a large amount of high rigidity borides, except improving hardening capacity, significantly can improve wear resisting property, and comparable high-chromium white cast iron improves 30 ~ 50%.

6, high tenacity boracic high-speed steel of the present invention is due to containing a large amount of chromium, has good antioxidant property, corrosion resistance nature.

7, high tenacity boracic high-speed steel of the present invention can adopt common electrosmelting, raw material choose ordinary scrap steel, ferrochrome, copper coin, ferromanganese, ferrosilicon, ferro-boron direct production, pour method composite inoculating inoculation in employing ferrotianium, cerium-based rare earth and nitrogenous substances and basic metal potassium wrap.Boride in alloy after Metamorphism treatment is evenly distributed on the good martensitic matrix of obdurability in isolated group is spherical, and impelling strength is significantly improved, and impelling strength ak reaches 10 ~ 12J/cm ², before Metamorphism treatment, improve about 30%, production technique is easy.

8, high tenacity boracic high-speed steel of the present invention has good mobility and is cast as performance, the methods such as ordinary sand casting, lost foam casting, dewax precision casting, permanent mold casting and resin bonded sand mould casting, centrifugal composite casting can be adopted shaping, foundry goods is not easily stained with sand, dead head is easy to cleaning, directly can be cast as the product of different shape.

9, high tenacity boracic high-speed steel of the present invention can quench at 700 ~ 780 DEG C, makes its matrix form metastable austenite tissue, makes alloy rigidity be reduced to 30 ~ below 35HRC, so that carry out mechanical workout; Can heat-treat under temperature within the scope of 920 ~ 1150 DEG C, it is made to harden to form metastable austenite, then air cooling sclerosis is adopted, to form martensitic stucture in alloy substrate, the material after thermal treatment can also be carried out temper at 150 ~ 200 DEG C, make alloy hardening after hardness reach HRC50 ~ 65, changes in hardness scope is large, can meet the service requirements of different operating mode, thermal treatment process is simple, with low cost.

10, high tenacity boracic high-speed steel of the present invention have good weldability, can gas cutting performance.

11, high tenacity boracic high-speed steel of the present invention is applied widely, can the required hot-work die of widespread use automobile, motorcycle, pressure die casting, extrusion casting, gravitational casting, forging molding etc. in the industrial production such as agricultural machinery and machinofacture; Be applied to the fields such as metallurgical roller, glass-forming die, slush pump pump case and impeller, welded tube extrusion roll, copper finish forge mould, hot upsetting mould and copper die casting, aluminium die casting, refractory brick forming die, grinder hammerhead, grinding roller, ball grinding machine lining board.High temperature resistant property is good, uses and do not soften under worst hot case.

Embodiment

Below in conjunction with embodiment, the invention will be further described.

Embodiment 1

A kind of high tenacity boracic high-speed steel and preparation method thereof chemical composition and mass percent thereof are; 0.40%C, 3.5%Cr, 0.6%Si, 3.8%Mn, 1.0%B, 1.2%Mo, 1.5%W, 0.7%V, 0.8%Cu, 0.5%Ti, 0.10%Ca, 0.08%Ce, 0.10%Y, 0.08%N, 0.10%Nb, 0.15%Mg, 0.065Ba, 0.07%K, S < 0.03%, P < 0.04%, surplus is Fe and inevitable impurity element.

Manufacturing technology steps is:

(1) boron supplying agent and inoculant manufacture:

By vanadium iron, ferrotianium, potassium oxide, calsibar alloy, be broken into 60 ~ 100 object powder, by 60 ~ 100 object BC, BN, B containing nitrogenous ferrochrome, nitrogenous vanadium iron ₂o ₃, Si ₃n ₄according to mass percent 1.0%B, 0.50%Ti, 0.10%V together with alterant element Rare-Earth Ce, reductive agent rare earth ferrosilicon, 0.10%Ca, 0.08%Ce, 0.10%Y, 0.08%N, 0.10%Nb, 0.15%Mg, 0.065Ba, mix after 0.07%K proportioning, adopt thickness 0.15mm soft steel steel band packaging, be rolled into diameter 8 ~ 15mm metal cored wire, or directly load in Low Carbon Steel Pipe;

(2) smelt

Steel scrap, ferrochrome are melted in electric furnace, after molten steel is melting down, adds copper coin, ferrosilicon, ferromanganese, molybdenum-iron, ferrotungsten, vanadium iron, control carbon content and reach requirement, after stokehold adjusting component is qualified, melt temperature is increased to 1560 DEG C, adds silicocalcium and carry out pre-deoxidation, add aluminium final deoxygenation;

(3) boron and rotten inoculation is added

Boron supplying agent manufactured by (1) and inoculant metal cored wire are passed through feeding wire machine, join according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or by the boron supplying agent manufactured by (1) and inoculant steel pipe, add to according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or carry out adding boron and rotten inoculation in the molten steel directly adding cast in ladle to;

(4) casting

Treated good molten steel is poured into foundry goods in sand mold or metal mold, or on whizzer, adopt centrifugal composite casting method to pour into skin for high boron, high chrome wear-resisting alloy steel, internal layer is the double metallic composite material of cast iron, cast alloy iron, spheroidal graphite cast iron or low alloy steel, melt cast temperature 1420 DEG C;

(5) thermal treatment

1. after casting finish, at 750 DEG C of temperature, insulation carries out subcritical air quenching in 4 hours, substrate degradation is become the mixture of ferrite and carbide, makes its matrix form metastable austenite tissue, and makes its hardness be reduced to 30 ~ 35HRC, so that carry out mechanical workout;

2. after casting finish, or machined after, foundry goods or workpiece are heat-treated 950 DEG C of insulations for 2 hours, it is made to harden to form metastable austenite, then air cooling is carried out to room temperature, to form martensitic microstructure in alloy substrate, the hardness of the material after this thermal treatment process process can reach HRC50 ~ 65;

3. the material after thermal treatment is carried out temper at 150 ~ 200 DEG C, tempering insulation time 2-4 hour, with stove air cooling to room temperature, to adjust hardness further;

Described boron supplying agent is industrial BC, B ₂o ₃, BN, wherein BC content is 50%, wherein B ₂o ₃content is 30%, BN content is 20%;

Described B ₂o ₃boron supplying agent is that industrial borax or boric acid are obtained after dehydration, adopts agent rare earth ferrosilicon to be directly reduced to B in molten steel;

Described N source is Si ₃n ₄with containing nitrogenous ferrochrome;

Described inoculant is Rare-Earth Ce, potassium oxide, calsibar alloy;

Table 1 wear-resisting multicomponent high boron alloy steel mechanical property

Hardness, HRC	Tensile strength, MPa	Impelling strength, J/cm 2	Fracture toughness property/MPam 1/2
				60.2	687.9	11.2	27.2

Embodiment 2

A kind of high tenacity boracic high-speed steel chemical composition and mass percent thereof are; 0.50%C, 4.0%Cr, 1.0%Si, 4.2%Mn, 0.90%B, 1.2%Mo, 1.4%W, 0.8%V, 0.6%Cu, 0.7%Ti, 0.10%Ca, 0.10%Ce, 0.14%Y, 0.08%N, 0.13%Nb, 0.15%Mg, 0.08Ba, 0.09%K, S < 0.03%, P < 0.04%, surplus is Fe and inevitable impurity element.

Manufacturing technology steps is:

(1) boron supplying agent and inoculant manufacture:

By vanadium iron, ferrotianium, potassium oxide, calsibar alloy, be broken into 60 ~ 100 object powder, by 60 ~ 100 object BC, BN, B containing nitrogenous ferrochrome, nitrogenous vanadium iron ₂o ₃, Si ₃n ₄according to mass percent 0.90%B, 0.70%Ti, 0.20%V together with alterant element Rare-Earth Ce, reductive agent rare earth ferrosilicon; 0.10%Ca, 0.10%Ce, 0.14%Y; 0.08%N; 0.13%Nb, 0.15%Mg, 0.08Ba; mix after 0.09%K proportioning; adopt thickness 0.12 ~ 0.25mm soft steel steel band packaging, be rolled into diameter 8 ~ 15mm metal cored wire, or directly load in Low Carbon Steel Pipe;

(2) smelt

Steel scrap, ferrochrome are melted in electric furnace, after molten steel is melting down, adds copper coin, ferrosilicon, ferromanganese, molybdenum-iron, ferrotungsten, vanadium iron, control carbon content and reach requirement, after stokehold adjusting component is qualified, melt temperature is increased to 1560 ~ 1620 DEG C, adds silicocalcium and carry out pre-deoxidation, add aluminium final deoxygenation;

(3) boron and rotten inoculation is added

Boron supplying agent manufactured by (1) and inoculant metal cored wire are passed through feeding wire machine, join according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or by the boron supplying agent manufactured by (1) and inoculant steel pipe, add to according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or carry out adding boron and rotten inoculation in the molten steel directly adding cast in ladle to;

(4) casting

Treated good molten steel is poured into foundry goods in sand mold or metal mold, or on whizzer, adopt centrifugal composite casting method to pour into skin for high boron, high chrome wear-resisting alloy steel, internal layer is the double metallic composite material of cast iron, cast alloy iron, spheroidal graphite cast iron or low alloy steel, melt cast temperature 1430 DEG C;

(5) thermal treatment

1. after casting finish, at 750 DEG C of temperature, insulation carries out subcritical air quenching in 5 hours, substrate degradation is become the mixture of ferrite and carbide, makes its matrix form metastable austenite tissue, and makes its hardness be reduced to 30 ~ 35HRC, so that carry out mechanical workout;

2. after casting finish, or machined after, foundry goods or workpiece are heat-treated 1100 DEG C of insulations for 3 hours, it is made to harden to form metastable austenite, then air cooling is carried out to room temperature, to form martensitic microstructure in alloy substrate, the hardness of the material after this thermal treatment process process can reach HRC50 ~ 65;

3. the material after thermal treatment is carried out temper at 150 ~ 200 DEG C, tempering insulation time 2-4 hour, with stove air cooling to room temperature, to adjust hardness further;

Described boron supplying agent is industrial BC, B ₂o ₃, BN, wherein BC content is 60%, wherein B ₂o ₃content is 30%, BN content is 10%;

Described B ₂o ₃boron supplying agent is that industrial borax or boric acid are obtained after dehydration, adopts agent rare earth ferrosilicon to be directly reduced to B in molten steel;

Described N source is Si ₃n ₄with containing nitrogenous ferrochrome;

Described inoculant is Rare-Earth Ce, potassium oxide, calsibar alloy;

Table 2 wear-resisting multicomponent high boron alloy steel mechanical property

Hardness, HSD	Bending strength, MPa	Impelling strength, J/cm 2	Fracture toughness property/MPam 1/2
				84.6	1241.6	10.9	26.4

Embodiment 3

A kind of high tenacity boracic high-speed steel chemical composition and mass percent thereof are; 0.6%C, 5.0%Cr, 1.15%Si, 5.2%Mn, 2.2%B, 2.6%Mo, 3.0%W, 1.5%V, 1.5%Cu, 1.2%Ti, 0.20%Ca, 0.25%Ce, 0.2%Y, 0.18%N, 0.3%Nb, 0.25%Mg, 0.15Ba, 0.13%K, S < 0.03%, P < 0.04%, surplus is Fe and inevitable impurity element.

Manufacturing technology steps is:

(1) boron supplying agent and inoculant manufacture:

By vanadium iron, ferrotianium, potassium oxide, calsibar alloy, be broken into 60 ~ 100 object powder, by 60 ~ 100 object BC, BN, B containing nitrogenous ferrochrome, nitrogenous vanadium iron ₂o ₃, Si ₃n ₄according to mass percent 2.2%B, 1.2%Ti, 0.30%V together with alterant element Rare-Earth Ce, reductive agent rare earth ferrosilicon; 0.20%Ca, 0.25%Ce, 0.2%Y; 0.18%N; 0.3%Nb, 0.25%Mg, 0.15Ba; mix after 0.13%K proportioning; adopt thickness 0.12 ~ 0.25mm soft steel steel band packaging, be rolled into diameter 8 ~ 15mm metal cored wire, or directly load in Low Carbon Steel Pipe;

(2) smelt

Steel scrap, ferrochrome are melted in electric furnace, after molten steel is melting down, adds copper coin, ferrosilicon, ferromanganese, molybdenum-iron, ferrotungsten, vanadium iron, control carbon content and reach requirement, after stokehold adjusting component is qualified, melt temperature is increased to 1620 DEG C, adds silicocalcium and carry out pre-deoxidation, add aluminium final deoxygenation;

(3) boron and rotten inoculation is added

Boron supplying agent manufactured by (1) and inoculant metal cored wire are passed through feeding wire machine, join according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or by the boron supplying agent manufactured by (1) and inoculant steel pipe, add to according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or carry out adding boron and rotten inoculation in the molten steel directly adding cast in ladle to;

(4) casting

Treated good molten steel is poured into foundry goods in sand mold or metal mold, or on whizzer, adopt centrifugal composite casting method to pour into skin for high boron, high chrome wear-resisting alloy steel, internal layer is the double metallic composite material of cast iron, cast alloy iron, spheroidal graphite cast iron or low alloy steel, melt cast temperature 1450 DEG C;

(5) thermal treatment

1. after casting finish, at 780 DEG C of temperature, insulation carries out subcritical air quenching in 6 hours, substrate degradation is become the mixture of ferrite and carbide, makes its matrix form metastable austenite tissue, and makes its hardness be reduced to 30 ~ 35HRC, so that carry out mechanical workout;

2. after casting finish, or machined after, foundry goods or workpiece are heat-treated 1150 DEG C of insulations for 4 hours, it is made to harden to form metastable austenite, then air cooling is carried out to room temperature, to form martensitic microstructure in alloy substrate, the hardness of the material after this thermal treatment process process can reach HRC50 ~ 65;

3. the material after thermal treatment is carried out temper at 200 DEG C, tempering insulation time 4 hours, with stove air cooling to room temperature, to adjust hardness further;

Described boron supplying agent is industrial BC, B ₂o ₃, BN, wherein BC content is 55%, wherein B ₂o ₃content is 25%, BN content is 20%;

Described B ₂o ₃boron supplying agent is that industrial borax or boric acid are obtained after dehydration, adopts agent rare earth ferrosilicon to be directly reduced to B in molten steel;

Described N source is Si ₃n ₄with containing nitrogenous ferrochrome;

Described inoculant is Rare-Earth Ce, potassium oxide, calsibar alloy;

Table 3 wear-resisting multicomponent high boron alloy steel mechanical property

Hardness, HSD	Bending strength, MPa	Impelling strength, J/cm 2	Fracture toughness property/MPam 1/2
				84.6	1241.6	10.9	26.4

Claims (2)

1. a high tenacity boracic high-speed steel, it is characterized in that chemical composition and the weight percent thereof of affiliated rapid steel are: 0.30 ~ 0.6%C, 3.5 ~ 5.0%Cr, 0.4 ~ 1.15%Si, 3.4 ~ 5.2%Mn, 0.8 ~ 2.5%B, 0.9 ~ 2.8%Mo, 1.0 ~ 3.2%W, 0.5 ~ 1.5%V, 0.6 ~ 1.8%Cu, 0.5 ~ 1.2%Ti, 0.05 ~ 0.20%Ca, 0.05 ~ 0.25%Ce, 0.05 ~ 0.2%Y, 0.02 ~ 0.18%N, 0.05 ~ 0.3%Nb, 0.12 ~ 0.25%Mg, 0.06 ~ 0.15Ba, 0.04 ~ 0.13%K, S < 0.03%, P < 0.04%, surplus is Fe and inevitable impurity element.

2. prepare high tenacity boracic high-speed steel and preparation method thereof as claimed in claim 1 for one kind, it is characterized in that: comprise following processing step:

(1) boron supplying agent and inoculant manufacture:

By vanadium iron, ferrotianium, potassium oxide, calsibar alloy, be broken into 60 ~ 100 object powder, by 60 ~ 100 object BC, BN, B containing nitrogenous ferrochrome, nitrogenous vanadium iron ₂o ₃, Si ₃n ₄according to mass percent 0.8 ~ 2.5%B, 0.5 ~ 1.2%Ti, 0.10 ~ 0.30%V together with alterant element Rare-Earth Ce, Y, 0.05 ~ 0.20%Ca, 0.05 ~ 0.25%Ce, 0.05 ~ 0.2%Y, 0.02 ~ 0.18%N, 0.05 ~ 0.3%Nb, 0.12 ~ 0.25%Mg, 0.06 ~ 0.15Ba, mix after 0.04 ~ 0.13%K proportioning, adopt thickness 0.12 ~ 0.25mm soft steel steel band packaging, be rolled into diameter 8 ~ 15mm metal cored wire, or directly load in Low Carbon Steel Pipe;

(2) smelt:

Steel scrap, ferrochrome are melted in electric furnace, after molten steel is melting down, adds copper coin, ferrosilicon, ferromanganese, molybdenum-iron, ferrotungsten, vanadium iron, control carbon content and reach requirement, after stokehold adjusting component is qualified, melt temperature is increased to 1560 ~ 1620 DEG C, adds silicocalcium and carry out pre-deoxidation, add aluminium final deoxygenation;

(3) boron and rotten inoculation is added:

Boron supplying agent manufactured by (1) and inoculant metal cored wire are passed through feeding wire machine, join according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or by the boron supplying agent manufactured by (1) and inoculant steel pipe, add to according to required mass percentage content in the molten steel smelted and add boron and rotten inoculation, or carry out adding boron and rotten inoculation in the molten steel directly adding cast in ladle to;

(4) casting:

Treated good molten steel is poured into foundry goods in sand mold or metal mold, or on whizzer, adopt centrifugal composite casting method to pour into skin for high boron, high chrome wear-resisting alloy steel, internal layer is the double metallic composite material of cast iron, cast alloy iron, spheroidal graphite cast iron or low alloy steel, melt cast temperature 1400 ~ 1450 DEG C;

(5) thermal treatment:

1. after casting finish, at 700 ~ 780 DEG C of temperature, be incubated 4-6 hour carry out subcritical air quenching, substrate degradation is become the mixture of ferrite and carbide, make its matrix form metastable austenite tissue, and make its hardness be reduced to 30 ~ 35HRC, so that carry out mechanical workout;

2. after casting finish, or machined after, foundry goods or workpiece are heat-treated 920 ~ 1150 DEG C of insulations for 2-4 hour, it is made to harden to form metastable austenite, then air cooling is carried out to room temperature, to form martensitic microstructure in alloy substrate, the hardness of the material after this thermal treatment process process can reach HRC50 ~ 65;

3. the material after thermal treatment is carried out temper at 150 ~ 200 DEG C, tempering insulation time 2 ~ 4 hours, with stove air cooling to room temperature, to adjust hardness further;

Described boron supplying agent is industrial BC, B ₂o ₃, BN, wherein BC content is 50 ~ 60%, wherein B ₂o ₃content is 20 ~ 30%, BN content is 10 ~ 20%;

Described B ₂o ₃boron supplying agent is that industrial borax or boric acid are obtained after dehydration, adopts agent rare earth ferrosilicon to be directly reduced to B in molten steel;

Described N source is VN, Si ₃n ₄with containing nitrogenous ferrochrome;

Described inoculant is Rare-Earth Ce, Y, potassium oxide, calsibar alloy.