CN1078674A - Produce the method for alloy powder - Google Patents

Abstract

The present invention relates to a kind of method of producing alloy powder, be particularly suitable for producing the steel-bonded cemented carbide powder end, it is characterized in that with water atomization through melting, water atomization, dewatered drying, ball mill crushing, sieve and the steel bonded carbide waste material of the various trades mark and the smear metal of machining made powder.

Description

Produce the method for alloy powder

The present invention relates to produce the method for alloy powder, be specially adapted to producing of steel-bonded cemented carbide powder end.

Steel bonded carbide (hereinafter to be referred as steel-bonded carbide) is the nearly 30 years a kind of new materials that grow up, this material by refractory carbide (mainly being tungsten carbide wc and titanium carbide TiC) as hard with steel (or alloy) serve as the bonding phase composition, it is a kind of novel high life tool die material.The preparation of this material is adopted the powder metallurgical technique method, that is: at present mostly

Hard phase powder preparation and parent metal powder preparation become finished product through ball milling mechanical mixture and press forming to sintering to following process.Therefore the preparation of former powder is one of master operation during steel-bonded carbide is produced, and directly the quality of subsequent technique and product is exerted an influence.

The main feature of original preparation steel-bonded carbide powder method is that powder obtains final raw material powder by the mechanical mixture mode to the hard phase powder that will produce with the different process method with boning mutually, raw material as the hard phase in steel-bonded carbide mainly are tungsten-carbide powder and titanium carbide powder, material as the bonding phase then is iron powder and intermediate alloy powder, they are according to the different trades mark, mix by ball milling by certain proportioning, obtaining required raw material mixed-powder, its preparation technology's flow process as shown in Figure 2:

Wherein:

1, tungsten carbide powder produces

The industry tungsten carbide normally at high temperature carries out carbonization by tungsten powder and carbon black and gets in hydrogen, accompanying drawing 3 is seen in technological process.

2, producing of carbonized titanium powder:

The industrial furnace charge of being prepared by titanium dioxide and carbon black usually at high temperature carries out carbonization in hydrogen or in the vacuum and gets, and accompanying drawing 4 is seen in its technological process.

3, producing of base steel forming element powder:

Main method commonly used in the industrial production has: mechanical crushing method, solid carbon reducing process, gas reduction method, atomization, electrolysis and carbonyl process or the like.

Production practices show, existing steel-bonded carbide complex manufacturing.And because steel-bonded carbide needs liquid-phase sintering, sintering temperature depends primarily on the eutectic temperature (liquidus temperature promptly occurring) of constituent element, therefore very sensitive to temperature, and that tungsten carbide is a steel-bonded carbide is more responsive to sintering temperature, because the eutectic temperature lower (about 1250 ℃) of C-Fe-W three elements, therefore sintering temperature is controlled at 1260-1300 ℃ of scope usually, the sintering temperature deviation is required to be controlled at ± 5 ℃ of scopes in, so general percent defective is higher.Require percent defective to be not more than 5% in the production, and reality often surpass this index (up to more than 10%).Simultaneously, at present generally the steel-bonded carbide that provides is provided is the rough forge base, so can produce a large amount of smear metals inevitably in the machining production process, stock utilization is lower, generally only reaches 70-80%, sometimes even be 50%.

The objective of the invention is to overcome above-mentioned shortcoming, improve technology, the rate of reducing the number of rejects and seconds improves stock utilization, and waste product and smear metal in the production process are fully used.

The present invention produces the steel-bonded carbide powder by water atomization, its main feature be utilize water atomization with the steel-bonded carbide waste material of the various trades mark and machining smear metal through melting, required alloyed powder is made in atomizing, its composition can be regulated in fusion process, and then obtain required trade mark steel-bonded carbide powder, make the material that becomes waste product obtain utilizing, and its performance is better than the steel-bonded carbide powder of mechanical mixture, its main technique flow process is as follows:

Waste material, machined are considered to be worth doing through heating melting, water atomization and dehydration, drying ball mill crushing must alloyed powder through sieving.

Further each critical process of above-mentioned technological process of the present invention is described further below:

1, heating melting:

The heating of employing medium-frequency induction furnace, temperature is controlled at 1300-1700 ℃, treat that furnace charge fusing back adds slag making such as the lime of the 2-3% of furnace charge weight, fluorite, the aluminium calcium powder deoxidation that adds the heavy 1-2% of furnace charge behind the removing slag again, refining 20-30 minute, the furnace charge degree of superheat maintains about 150 ℃, uses metallic aluminium (consumption be molten metal 1 ‰) deoxidation at last, and adds 1 of charging weight.4-2.0% high purity graphite or other carburant (for example wooden carbon, rubble electrode ink, anthracite and the pig iron etc.).

2, water atomization:

Melted furnace charge poured in the bottom pour ladle 1 that is preheated to more than 800 ℃ carry out powder by atomization.The water atomization course of work is as follows:

Liquation is injected bottom pour ladle, flow into atomization tank 2 by the bottom pour ladle end opening, the powdered that is crashed to pieces at V-arrangement water under high pressure plate intersection place 3, and flow down from conduit 4 hits and is cushioned on turbulator 5 and disperses, and falls into integration jar 6 slowly.Owing to the continuous injection water under high pressure, the unnecessary water yield of its increase is discharged from overfall 11, uses through the settling tank filtration cycle in jar.

3, dehydration is had illicit relations with dried:

Powder after the atomizing takes out from the integration jar after centrifuge dewatering, and place 90-100 ℃ baking oven under moving air, to dry, time is 24-48 hour, or dries in moving air in 400-520 ℃ stove in the flash baking mode, and drying time is 2-5 minute.

4, ball mill crushing:

Consider the grain size category of atomizing back powder, in order to improve the fine powder rate, for the ball mill fragmentation of steel-bonded carbide powder.The ball milling form adopts the dry type ball milling, and ball milling body material is different mutually different because of hard, and tungsten carbide is that steel-bonded carbide can adopt the WC-Co sintered carbide ball; Titanium carbide system adopts steel ball.Ball milling body diameter is the 10-20 millimeter, and ratio of grinding media to material (weight ratio) is 2: 1, and ball load is 40% of a ball grinding cylinder volume, and the ball milling time is 20-40 hour.

Adopt the present invention to produce the steel-bonded cemented carbide powder end, steel bonded carbide waste material and the goods machined smear metal thereof adopted in the traditional mode of production process are fully utilized, improved stock utilization, have bigger economic and social benefit.In addition, because the technology that adopts is fairly simple, deoxidation and anti-decarburization way are reasonable, and the flash baking method both prevented increasing considerably of oxygen, and higher production efficiency is arranged again.

Description of drawings:

Fig. 1 is the schematic diagram of the used water atomization plant of the present invention, among the figure:

1 is that bottom pour ladle, 2 is that atomization tank, 3 is that V-arrangement water under high pressure plate intersection, 4 is that conduit, 5 is that turbulator, 6 is that integration jar, 7 is that high pressure nozzle, 8 is that high-pressure water pipe, 9 is that venting, 10 is that clear water overflow tank, 11 is that clear water overfall, 12 is that powder settling tank, 13 is that nitrogen inlet, 14 is that smelting furnace, 15 molten metals, 16 are the atomizing steel-bonded cemented carbide powder end of being produced.

Fig. 2 and Fig. 3, Fig. 4 are respectively the reparation technology flow process of the original preparation technology's flow process of steel-bonded carbide powder and tungsten carbide powder, carbonized titanium powder.

Embodiment:

Example 1

Raw material: DT40 steel bonded carbide scrap (WC 40%, Cr0.8%, and Mo1.7%, Ni1.7%, Mn0.5%, C0.6%, all the other are Fe) 8Kg; DT40 smear metal 12Ks, 20Kg altogether.

Auxiliary material: fluorite, lime, aluminium calcium powder, metallic aluminium.

Smelting technology: raw material are gone into behind the stove with the middle frequency furnace heating, and peak power is 60KW, begins fusing after furnace charge is warmed up to 1300 ℃, treats to add fluorite when furnace charge melts 80% left and right sides, lime carries out slag making, and addition is 3% of a furnace charge.Claw the part slag after furnace charge melts fully, and make new slag, adding aluminium calcium powder deoxygenation refining addition then is 1% of furnace charge, refining 20-30 minute.Make smelting temperature rise to 1600 ℃ (about 150 ℃ of degrees of superheat) simultaneously and skim at last, and carry out deoxidation (consumption is a molten metal 1 ‰) with the metallic aluminium calcium powder.

Atomization process:

Bottom pour ladle is preheating to more than 800 ℃, and small opening is got 7 millimeters of φ.Water atomization plant is the positive-pressure closing formula, and V-type nozzle, nozzle outlet pressure are 6MPa, the liquation after the refining is injected bottom pour ladle, at last by taking out powder in the integration jar.

Subsequent technique:

Atomized powder centrifugal dehydration, centrifuge speed are 7000 rev/mins.

Dehydrated powder places 90-100 ℃ baking oven, dries under moving air, and drying time is 24-48 hour.

Atomized powder is broken in cylindrical ball mill, charge be cylindrical shell long-pending 1/3,10 millimeters of ball radius φ, material is a carbide alloy, ball material weight ratio 2: 1, and the ball milling time is 24-48 hour, ball-milled powder is crossed behind 160 mesh sieve stand-by, and oversize powder is ball milling again.

Example 2

Raw material: DT40 scrap 32Kg.

Auxiliary material: fluorite, lime, aluminium calcium powder, metallic aluminium, mild steel material (45# or A ₃, addition be DT40 5%) high purity graphite (addition be DT40 1.4%).

Smelting technology: DT40 and mild steel material are packed in the stove simultaneously, heating then, and (before the lid slag) adds high purity graphite piece in fusion process.

Slag making and refinery practice are with embodiment 1, and the liquation tapping temperature is 1650 ℃.

Atomization process:

The bottom pour ladle aperture is 6 millimeters of φ, other the same example 1.

Subsequent technique: the same example 1 of dewatering, oven dry is carried out with immediate mode, is 520 ℃ of liquid zones with 2-3 branch clock time by 300 millimeters of length, temperature, feeds moving air with the pusher rightabout to burner hearth, and the tolerance per minute is 1-3m ³

Ball-milling technology: with example 1.

Claims (8)

1, a kind of method of producing alloy powder, be particularly suitable for producing the steel-bonded cemented carbide powder end, it is characterized in that with water atomization through melting, water atomization, dewatered drying, ball mill crushing, sieve and the steel bonded carbide waste material of the various trades mark and the smear metal of machining made alloy powder.

2, according to right 1 described method, adopt the intermediate frequency furnace heating when it is characterized in that melting, temperature is 1300-1700 ℃, after slag making, added aluminium calcium powder deoxygenation refining again 20-30 minute, the heating degree of superheat maintains about 150 ℃, use the metallic aluminium deoxidation at last, and add high purity graphite or other carburant that accounts for into charging weight 1.4-2.0%.

3, the method according to claim 1, furnace charge melted when it is characterized in that water atomization carries out powder by atomization in the bottom pour ladle that is preheating to more than 800 ℃.

4, the method according to claim 1 is characterized in that the flow process of water atomization is: liquation injects bottom pour ladle and flows into atomization tank through end opening, smashes powdered through V-arrangement water under high pressure plate, arrive again conduit through the turbulator buffering, disperse to arrive at last the accumulated powder jar.

5, the method according to claim 1 is characterized in that cemented carbide powder behind centrifuge dewatering, flash baking in moving air in 400-520 ℃ in continuous drying stove, drying time 2-5 minute.

6, the method according to claim 1, when it is characterized in that ball mill grinding, ball milling body material is different and different according to the hardness of producing material, ball milling body diameter is between the 10-20 millimeter, ball material weight ratio is 2: 1, and the device amount is 40% of a ball grinding cylinder volume, and the ball milling time is 20-40 hour.

7, according to claim 1 and 6 described methods, be that steel-bonded carbide can adopt the WC-CO sintered carbide ball for tungsten carbide when it is characterized in that ball milling, system adopts steel ball for titanium carbide.

8, according to claim 1 and 5 described methods, it is characterized in that the powder after centrifugal dehydration also can place 90-100 ℃ baking oven, under the moving air condition, to dry, the time is 24-48 hour.

Images