CN103266269A - HB500 grade hot continuous rolling high strength wear-resisting steel and production method thereof - Google Patents

Abstract

The invention relates to HB500 grade hot continuous rolling high strength wear-resisting steel which comprises the components in percentage: 0.21-0.30% of C, less than or equal to 0.20% of Si, 0.8-1.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.10-0.40% of Mo, 0.050-0.20% of Ti, 0.0005-0.0030% of B and less than or equal to 0.0050% of N, wherein the condition is met that Ti/N is greater than or equal to 10, and Mo/Ti is greater than or equal to 2. The preparation method comprises the following steps: smelting and continuously casting to blanks; directly heating the blanks; continuously rolling; batching; finishing and cutting; heating and insulating by a thermal treatment furnace; quenching by a roller type quenching machine; performing water cooling to reach room temperature; and annealing at low temperature and air-cooling to room temperature. According to the invention, the production cost is lower, and the Brinell Hardness of the steel plate after thermal treatment reaches 480-520 and KV2 at minus 40 DEG C is greater than or equal to 30J. The steel plate is excellent in shape, and the inequality in the length direction is less than or equal to 13mm/1000mm. The steel plate is good in cold roll forming performance.

Description

A kind of HB500 level hot continuous rolling high-strength wearable steel and production method thereof

Technical field

The present invention relates to wear resisting steel and production method thereof, belong to HB500 level hot continuous rolling high-strength wearable steel and production method thereof particularly.

Background technology

Wear resisting steel is a class high-abrasive material that is widely used in various wear working conditions such as metallurgy, mine, building materials, electric power, railway and military affairs, is one of most important steel grade of present China's construction machinery industry.In recent years, along with manufacturing development, thin size high-tensile wear resisting steel becomes new demand direction.Because the wear resisting steel Working environment is comparatively abominable, require it must possess enough hardness and resist wearing and tearing, possess certain toughness simultaneously and prevent impact fracture, must guarantee also after the thermal treatment of thin size high-tensile wear resisting steel that in addition good plate shape and good cold roll forming performance are to satisfy process requirements.

The production technology of wear resisting steel development both at home and abroad at present is very fast, has formed the standards system of system and perfect product line.But in these steel grades, be to guarantee the good mechanical performance, usually by add Ni, Cr, valuable alloys such as Nb, V are realized, as by retrieval:

The CN201010185080 patent documentation that Chinese patent application number is, it discloses a kind of 500HB grade wear-resisting steel plate, and its chemical element quality per distribution ratio is: C:0.23～0.33%; Si:0.10～0.50%, Mn:0.50～1.50%, Cr≤1.50%; Mo≤0.80%, Al:0.01～0.10%, Ti:0.01～0.10%, B:0.0005～0.0040%, RE:0.01～0.08%, Ca:0.002～0.010%, Ni≤2.50%, P≤0.050%, S≤0.030%, surplus are Fe and other unavoidable impurities; And the quality percentage composition of above-mentioned each chemical element satisfies: 1.50% 〉=(Si+Mn) 〉=0.50%; 0.15% 〉=(Al+Ti) 〉=0.03%.Procedure of processing is: smelting, casting, heating, rolling, cooling, quenching, tempering.The steel plate that makes by this method has the favorable mechanical processing characteristics, and hardness can reach more than the 508-523HB, and-20 ℃ of summers are than impact of collision merit 48-73J.

Chinese patent application number is the patent documentation of CN200910090637, it discloses a kind of production technology method of low content alloy ultrahigh hardness wear-resistant steel plate, specifically, steel plate after will rolling is strengthened the control cooling, opening cold temperature is 850～780 ℃, speed of cooling is controlled at 15～30 ℃/s, 350～550 ℃ of final cooling temperatures; Air cooling is to room temperature afterwards, and reheat 10min～120min is quenched to room temperature, and quenching temperature is 950～900 ℃; Steel plate after quenching is carried out 100～400 ℃ of tempering, and tempering time is at 20min～180min.Composition is that C:0.2～0.25%, Si:0.3～2.0%, Mn:1.5～1.9%, Cr:0.7～1.4%, B:0.002～0.005%, Ni≤0.5%, Mo≤0.4%, Nb≤0.1%, V≤0.07%, Ti≤0.04%, alloy total amount are less than 6% by weight percentage, all the other are Fe and unavoidable impurities, steel plate thickness is 10-50mm, and hardness is greater than 500HB.

Chinese patent application number is the patent documentation of CN201210002787, it discloses a kind of high-strength abrasion-proof steel plate and preparation method thereof, and this steel plate comprises following component (wt%): C 0.28～0.35%, Si 0.10～0.60%, Mn 0.7～1.0%, P≤0.025%, S≤0.010%, Cr 0.4～0.8%, Mo 0.10～0.60%, Nb 0.01～0.05%, V 0.01～0.08%, Ti 0.005～0.05%, B 0.001～0.003%, all the other are Fe and impurity; This preparation method comprises operations such as smelting, continuous casting, controlled rolling, press quenching and low-temperaturetempering.The present invention is by carrying out appropriate design to alloying constituent and production technique, product Brinell hardness number＞the 500HB that makes, Hardness Distribution is even,-20 ℃ of impelling strength 〉=24J, microtexture is tempered martensite, welding, cold-bending property and steel plate template are all good, and production technique is simple, cycle is short, and cost is low, can be widely used in the engineering machinery manufacturing.

Chinese patent application number is the patent documentation of CN201110326202.1 ,It discloses " a kind of Brinell hardness be 470～520 shovel loader and digger shovel blade with steel and production method ".Its chemical ingredients and weight percent are: C 0.26～0.35%, Si≤0.20～0.50%, Mn 1.0～1.50%, P≤0.020%, S≤0.015%, Cr 0.20～0.70%, Ti 0.020～0.06%, Mo≤0.35%, B 0.0005～0.0050%, Cu≤0.3%, As≤0.018%, all the other are Fe and unavoidable impurities.Production stage: carry out desulfurizing iron, the converter top bottom blowing, the RH vacuum-treat, the whole process protection pours into continuously cast bloom; The continuously cast bloom heating; Breaking down; Finish rolling; Stand-by (quenching; Tempering).Composition of the present invention is simple, process stabilizing, and the mechanical property excellence, the cost performance height, good welding performance, hardened and tempered steel plate can directly weld when not preheating, and cold-bending property is good ,-40 ℃ of KV ₂〉=18-36J.

Above-mentioned prior art has all been added Ni, Cr, the valuable alloy of Nb, V to some extent, has caused the increase of production cost and the waste of resource; And it (is that the thickness specification 〉=15mm), the hot continuous rolling thin panel products thick less than 15mm do not relate to that the product specification of above-mentioned steel grade concentrates on uni-tension rolling plate of moderate thickness product.

The major technique characteristics of this patent are as fundamental element with C, Mn, utilize the Ti of relative low price as main strengthening element, add a spot of Mo control Ti precipitate size, cooperate the B of trace to improve steel plate hardening capacity again, compound action by Mo, Ti, what obtain nano-scale (5-10nm) that a large amount of disperses distribute in rolling, heat treatment process contains the Ti precipitate, improves the obdurability of steel plate, and the steel plate cost of alloy is lower.

Summary of the invention

The objective of the invention is at the prior art metallic element many, it is many to add noble element, the deficiency that production cost is high, provide a kind of can be under the prerequisite that guarantees mechanical properties such as the hardness of steel plate, intensity, not only use metallic element few, noble element is common element except Mo, produce instinct and reduce by 20% HB500 level hot continuous rolling high-strength wearable steel and production method thereof.

Realize the measure of above-mentioned purpose:

A kind of HB500 level hot continuous rolling high-strength wearable steel, its component and weight percent content are: C:0.21～0.30%, Si :≤0.20%, Mn:0.8～1.60%, P :≤0.015%, S :≤0.005%, Mo:0.10～0.40%, Ti:0.050～0.20%, B:0.0005～0.0030%, N≤0.0050%, all the other are Fe and unavoidable impurities, and satisfy: Ti/N 〉=10, Mo/Ti 〉=2.

Preferably: C:0.24～0.30%, Si :≤0.08%, Mn:0.9～1.40%, Mo:0.15～0.40%, Ti:0.06～0.15%, B:0.0005～0.0020%.

Produce a kind of method of HB500 level hot continuous rolling high-strength wearable steel, its step:

1) smelting also, continuous casting becomes base;

2) strand is heated: the strand that rolls off the production line is directly into process furnace, and the control charging temperature is not less than 700 ℃, and Heating temperature is 1280～1350 ℃, and heat-up time was at 150～180 minutes;

3) carry out continuous rolling, control roughing temperature out is at 1030～1070 ℃, and the finish rolling finishing temperature is at 800～840 ℃;

4) batch, the control coiling temperature is at 480～520 ℃;

5) carry out the finishing cutting;

6) carry out heat tracing at heat treatment furnace, 870～890 ℃ of Heating temperatures, soaking time is: be the data of the thickness of slab H+20 millimeter sum of unit with the millimeter, time unit is minute;

7) adopt the roller press type quenching press to quench, quenching temperature is controlled at 870～890 ℃;

8) water-cooled is to room temperature, and the control of water spray flow angle is at 20～30 °, and the water yield ratio of control steel plate upper and lower surface is 0.6～0.9;

9) carry out low-temperaturetempering, tempering temperature is controlled at 180 ℃～220 ℃, and tempering insulation time is: be the data of the thickness of slab H+70 millimeter sum of unit with the millimeter, time unit is minute; After the tempering insulation finished, air cooling was to room temperature.

The mechanism of action of interalloy element of the present invention and main technique point

C: the content of C is 0.21-0.30% in the steel of the present invention, C is one of element of indispensable raising steel strength in the steel, in order to guarantee high tenacity, good weldability and cold-forming etc., C content is limited between the 0.21-0.30%, not only can guarantee the intensity of steel but also be fit to production operation.

Mn: be to improve the tensile strength of steel and the element of yield strength, it does not significantly worsen the deformability of steel.In general, Mn content is favourable in the toughness to the raising weld metal below 2%.For the intensity and the hardening capacity that guarantee steel, Mn content is chosen in 0.8～1.6%.。

The intensity of the steel of Si:Si has certain strengthening effect, and still, plasticity and the toughness of the steel of Si are harmful to, must its content in steel of control.

P, S:P have disadvantageous effects such as causing segregation, deterioration welding property, the low-temperature impact toughness that limits the reduction steel, raising ductile-brittle transition temperature easily in steel.Be mingled with but then be combined formation MnS with the easy Mn with steel in, thereby influence the low-temperature impact toughness of steel.Therefore, among the present invention, should reduce as far as possible P, S element to rigidity can disadvantageous effect, thereby with its control at P≤0.015%, S＜0.005%.

Mo:Mo can effectively prolong the incubation period of perlitic transformation, and ferrite and perlitic range are moved to right, but very little to the influence of bainitic transformation.Mo can reduce the diffusibility of carbide forming element such as Ti etc., thereby hinders the formation of carbide, postpones the precipitation process of carbide, effectively increases the TiC precipitate quantity of steel grade nano-scale.

Ti:Ti is main alloy element of the present invention, adding Ti element can play the effect of dispersion-strengthened and crystal grain thinning, Ti in continuous casting and rolling steel flow process to separate out situation as follows: 1) at continuous casting and cooling stages, with TiN and liquation (account for total Ti content 15%); 2) in the soaking stage; The alligatoring of TiN particle; 3) the tandem rolling stage, TiC deformation inductdion in austenite is separated out; 4) cold stage of layer takes place that TiC is alternate to separate out; 5) batching stage TiC separates out in ferrite.Experimental results show that, the size of particles that Ti separates out in ferrite is significantly less than the size of precipitation particles in the austenite, strengthening effect is more obvious, so more wish the tiny TiC obtain separating out in the coiling process, precipitation phase and the size of particles of therefore controlling Ti are the keys of rationally utilizing Ti.

B:B can significantly improve the hardening capacity of steel, can be unfavorable to the toughness of steel in the crystal boundary enrichment but add excessive B, so its content control is 0.0005～0.0020%.

N: the N in the steel can be combined with Ti; in casting process, form oarse-grained TiN; in strand heat-processed subsequently; this TiN particle does not dissolve substantially; performance is caused disadvantageous effect; also reduced simultaneously the amount of separating out to the favourable nano level TiC of performance, so must control by low N in the smelting process, N content is controlled below 0.0050%.

Ti/N: steel grade Ti at first is combined with N and is formed TiN, is combined the enough disperses of acquisition with C and separates out the TiC particle for guaranteeing residue Ti, gives full play to the precipitation strength effect of Ti, stoicheiometry Ti/N 〉=10 of Ti and N in the steel.

But the interpolation refinement of Mo/Ti 〉=2:Mo element contain the size of Ti precipitated phase in the steel, thereby what is more important Mo has participated in the quantity that separating out of precipitated phase increased precipitated phase directly, also can suppress simultaneously or precipitated phase the growing up under austenitic temperature of slowing down significantly., the precipitated phase of the tiny nano-scale (5-10nm) that the compound adding of Mo, Ti obtains gets content apparently higher than the steel of single adding Ti.For guaranteeing that enough Mo element participates in containing the Ti precipitate and separates out, obtain the favourable tiny nano-scale precipitated phase of obdurability and in heat-processed subsequently, suppress it and grow up, in the steel chemical ingredients proportioning of Mo/Ti necessary 〉=2.

In technology: by the continuously cast bloom straight dress technology (continuous casting billet skin temperature 〉=700 ℃) that rolls off the production line, save energy significantly, strand plasticity is better during high temperature simultaneously, can effectively prevent the insufficient disconnected base accident that causes of thermal stresses release in the strand process of cooling; Lower finish rolling finishing temperature (800-840 ℃ of finish rolling finishing temperature) can guarantee to obtain when steel plate of the present invention is rolling in the non-recrystallization district austenite crystal of flattening, obtains bigger deformation energy storage; Lower coiling temperature (480～520 ℃) but crystal grain thinning reduces the size of the compound precipitated phase of Ti-Mo in the coiling process simultaneously; Suitable quenching temperature (870-890 ℃) and soaking time can guarantee the steel plate complete austenitizing, and austenite crystal is not grown up simultaneously, can obtain tiny lath martensite in quenching process; The control of quenching process water spray flow angle between 20～30 ° and the water yield of controlling the steel plate upper and lower surface than 0.6～0.9, can effectively control the distortion of steel plate upper and lower surface, back steel plate roughness guarantees to quench; Suitable tempering temperature (tempering temperature is controlled at 180-220 ℃) can reduce quenching stress with soaking time, improves steel plate toughness, finally obtains the steel plate of obdurability coupling.

The present invention compares with traditional high-strength wearable steel and has the following advantages:

(1) cost performance height, compare as main alloy element with traditional high-strength wearable steel Ni, V, Nb, adopt the cheap relatively Ti of cost to cooperate a small amount of Mo element as main alloy element, made production cost lower, had good economic benefit and social benefit;

(2) after heat treatment, the steel plate Brinell hardness reaches 480～520 ,-40 ℃ of KV ₂〉=30J satisfies user's service requirements fully;

(3) after heat treatment steel-plate shape is good, length direction roughness≤13mm/1000mm;

(4) steel plate cold bending good forming ability adopts B=30mm clod wash sample, and laterally 180 ° of clod wash D=4a bendings are qualified.

Embodiment

Below the present invention is described in detail:

Table 1 is the chemical ingredients value tabulation of various embodiments of the present invention and Comparative Examples;

Table 2 is the main rolling technological parameter tabulation of various embodiments of the present invention and Comparative Examples;

Table 3 is various embodiments of the present invention and the tabulation of Comparative Examples thermal treatment process;

Table 4 is various embodiments of the present invention and Comparative Examples mechanical properties test result.

Various embodiments of the present invention are according to following steps production:

Its step:

1) smelting also, continuous casting becomes base;

2) to the strand heating, continuous caster rolls off the production line strand directly into stove, and the control charging temperature is not less than 700 ℃, and Heating temperature is 1280～1350 ℃, and heat-up time was at 150～180 minutes;

3) carry out continuous rolling, control roughing temperature out is at 1030～1070 ℃, and the finish rolling finishing temperature is at 800～840 ℃;

4) batch, the control coiling temperature is at 480～520 ℃;

5) carry out the finishing cutting;

6) steel plate is gone into heat treatment furnace and is carried out heat tracing, 870～890 ℃ of Heating temperatures, and soaking time is: be the data of the thickness of slab H+20 millimeter sum of unit with the millimeter, time unit is minute;

7) adopt the roller press type quenching press to quench, quenching temperature is controlled at 870～890 ℃;

8) water-cooled is to room temperature,, the control of water spray flow angle between 20～30 ° and the water yield of controlling the steel plate upper and lower surface than 0.6～0.9;

9) carry out low-temperaturetempering, tempering temperature is controlled at 180 ℃～220 ℃, and tempering insulation time is: be the data of the thickness of slab H+70 millimeter sum of unit with the millimeter, time unit is minute; After the tempering insulation finished, air cooling was to room temperature.

Table 1 various embodiments of the present invention and Comparative Examples chemical ingredients (Wt%)

Sequence number	C	Si	Mn	P	S	Mo	Ti	B	N	Ti/N	Mo/Ti
												1	0.30	0.02	0.90	0.015	0.004	0.24	0.12	0.0009	0.0031	38	2.0
2	0.28	0.02	1.05	0.011	0.001	0.32	0.15	0.0030	0.0042	36	2.1
												3	0.25	0.08	1.40	0.013	0.002	0.15	0.06	0.0027	0.0028	28.5	2.5
4	0.24	0.05	1.21	0.006	0.002	0.28	0.12	0.0012	0.0036	33	2.3
												5	0.24	0.05	1.37	0.011	0.005	0.40	0.08	0.0018	0.0050	16	5.0
6	0.27	0.07	1.13	0.008	0.001	0.36	0.13	0.0005	0.0043	30	2.76
												Contrast 1	0.25	0.06	1.20	0.012	0.003	—	0.10	0.0020	0.0035	29	—
Contrast 2	0.23	0.03	1.18	0.014	0.004	0.30	0.02	0.0022	0.0040	5	15

Table 2 various embodiments of the present invention and Comparative Examples hot continuous rolling process

Table 3 various embodiments of the present invention and Comparative Examples thermal treatment process

Table 4 various embodiments of the present invention and Comparative Examples performance test result

Annotate: the non-standard sample of 7.5*10*55mm is adopted in 8mm, the test of 10mm steel plate impelling strength.

Above-described embodiment only exemplifies for the best, and is not to be restriction to embodiments of the present invention.

Claims (3)

1. HB500 level hot continuous rolling high-strength wearable steel, its component and weight percent content are: C:0.21～0.30%, Si :≤0.20%, Mn:0.8～1.60%, P :≤0.015%, S :≤0.005%, Mo:0.10～0.40%, Ti:0.050～0.20%, B:0.0005～0.0030%, N≤0.0050%, all the other are Fe and unavoidable impurities, and satisfy: Ti/N 〉=10, Mo/Ti 〉=2.

2. a kind of HB500 level hot continuous rolling high-strength wearable steel as claimed in claim 1 is characterized in that: C:0.24～0.30%, Si :≤0.08%, Mn:0.9～1.40%, Mo:0.15～0.40%, Ti:0.06～0.15%, B:0.0005～0.0020%.

3. the method for the described a kind of HB500 level hot continuous rolling high-strength wearable steel of production claim 1, its step:

1) smelting also, continuous casting becomes base;

2) strand is heated: the strand that rolls off the production line is directly into process furnace, and the control charging temperature is not less than 700 ℃, and Heating temperature is 1280～1350 ℃, and heat-up time was at 150～180 minutes;

3) carry out continuous rolling, control roughing temperature out is at 1030～1070 ℃, and the finish rolling finishing temperature is at 800～840 ℃;

4) batch, the control coiling temperature is at 480～520 ℃;

5) carry out the finishing cutting;

6) carry out heat tracing at heat treatment furnace, 870～890 ℃ of Heating temperatures, soaking time is: be the data of the thickness of slab H+20 millimeter sum of unit with the millimeter, time unit is minute;

7) adopt the roller press type quenching press to quench, quenching temperature is controlled at 870～890 ℃;

8) water-cooled is to room temperature, and the control of water spray flow angle is at 20～30 °, and the water yield ratio of control steel plate upper and lower surface is 0.6～0.9;

9) carry out low-temperaturetempering, tempering temperature is controlled at 180 ℃～220 ℃, and tempering insulation time is: be the data of the thickness of slab H+70 millimeter sum of unit with the millimeter, time unit is minute; After the tempering insulation finished, air cooling was to room temperature.