CN105296833A

CN105296833A - Hard alloy

Info

Publication number: CN105296833A
Application number: CN201410336632.5A
Authority: CN
Inventors: 匡永刚
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-07-16
Filing date: 2014-07-16
Publication date: 2016-02-03

Abstract

The invention provides hard alloy. The hard alloy comprises, by weight, 6-18% of nickel, 0.5-1.5% of chromium carbide, and the balance tungsten carbide. The hard alloy is simple in component, high in hardness, good in abrasive resistance and high in corrosion resistance. A preparation method of the hard alloy includes the steps of raw material preparation, wet grinding, drying, pressing, sintering and the like. A raw material comprises, by weight, 8-15% of nickel powder, 0.5-1.5% of chromium carbide powder, and the balance tungsten carbide powder. Forming agents are added during preparation. Spray drying is conducted at 90-100 DEG C. A dewaxing and sintering integrated process is adopted. A furnace is heated to 450-550 DEG C within 25-45 hours to complete forming agent removal and then heated within 7-9 hours till a product has liquid phase. High-purity argon is introduced into the furnace, the furnace is heated to the final sintering temperature of 1460-1480 DEG C within 1-2 hours, the temperature is kept for 30-60 min, then high-purity argon is introduced into the furnace again, the temperature continues to be kept for 30-60 min, and then cooling is conducted. By adopting the preparation method, alloy of a general specification can be prepared, and the preparation and performance requirements of large-scale alloy can be met.

Description

A kind of Wimet

Technical field

The present invention relates to a kind of Hardmetal materials and preparation method thereof, especially a kind of Hardmetal materials and preparation method.

Background technology

Wimet has obvious advantage in the mold for forming, wear ring etc. of Powder Metallurgy Industry ferromagnetism powder, not only has very high hardness and wear resistance, and sticking to mould when can avoid ferromagnetism powder compacting, improves the resistance to corrosion of wear ring.In existing alloy manufacturing methods, by adding multiple element, putting forward heavy alloyed hardness and intensity by sub-zero treatment, ageing treatment, but the effect that Wimet carries out the mode such as deep cooling, ageing treatment also exists dispute, the product larger to substance is also unsuitable for or effect is difficult to detect.Chinese patent application " a kind of Wimet containing vanadium and preparation method " (200810031230.9), simultaneously containing the Cr3C2 of 0.5 ~ the 3.0% and VC of 0.3 ~ 2.5% in alloy, adopt vacuum-drying, sintering temperature 1430 ~ 1460 DEG C, soaking time 30 ~ 60 minutes, and be filled with 3 ~ 5MPa(and equal 30 ~ 50bar) high-purity argon gas, the product hardness of production reaches >=86HRA, bending strength >=3000MPa, density 13.60-14.60g/cm3.But the control difficulty of this alloy carbon content is larger, the consistence of material and the homogeneity of pressed density are difficult to ensure, particularly easily there is crackle, flexural deformation in massive article (substance >=10Kg or diameter >=150mm), can not ensure the densification of massive article and the homogeneity of performance.

Summary of the invention

The present invention is directed to above-mentioned deficiency, provide a kind of Wimet containing chromium, component is simple, and hardness is high, wear resistance good, resistance to corrosion is strong, and preparation method can not only prepare general requirements alloy, can meet preparation and the performance requriements thereof of large-scale alloy simultaneously.

Wimet of the present invention, take wolfram varbide as main ingredient, its composition and weight percent are:

Nickel: 6% ~ 18% chromium carbide: 0.5% ~ 1.5% wolfram varbide: surplus.

As improvement, the composition of this alloy and weight percent are: nickel: 8% ~ 15% chromium carbide: 0.5% ~ 1.0% wolfram varbide: surplus.

As further improvement, the composition of this alloy and weight percent are: nickel: 11% chromium carbide: 0.75% wolfram varbide: surplus.

The preparation method of Wimet of the present invention, comprise the operations such as preparation of raw material, wet-milling, drying, compacting, sintering, material composition and weight percent are nickel powder 8% ~ 15%, carbonization chromium powder 0.5% ~ 1.5%, tungsten carbide powder surplus; Forming agent is added during preparation of raw material.

Drying process adopts spraying dry, and drying temperature is 90 ~ 100 DEG C.

Sintering adopts dewaxing and sintering integrated metallization processes, and furnace temperature was warming up to 450 DEG C ~ 550 DEG C in 25 ~ 45 hours, completed forming agent and removed, and passed into the hydrogen of dew point-60 DEG C; Then in 7 ~ 9 hours, be warming up to product again occur liquid phase, this stage furnace pressure≤0.8mbar; In stove, the high-purity argon gas of 40 ~ 80mbar, volume percent >=99.99% is filled with again after there is liquid phase, within 1 ~ 2 hour, be warming up to final sintering temperature 1460 ~ 1480 DEG C, be incubated the high-purity argon gas passing into 50bar, volume percent >=99.99% after 30 ~ 60 minutes again, continue insulation and cool after 30 ~ 60 minutes.

Except hard phase wolfram varbide, Binder Phase nickel, only Cr3C2 is with the addition of in raw material, and Cr3C2 alloy bonding mutually in dissolve each other in a large number, irrelevant with carbon content height, therefore in alloy, carbon content control is easier to, guarantee performance and size and precision, its dosage is lower simultaneously, does not affect intensity and the porosity of alloy.Use enclosed spraying dry farthest to avoid impurity and enter material, improve stability and the consistence of material simultaneously, ensure that the even of all even pressed density of compacting fashion material.Utilize dewaxing-sintering furnace, adopt dewaxing and sintering integrated metallization processes, can ensure evenly removing of forming agent, farthest improve control accuracy and the homogeneity of carbon content, make the flexural deformation of product little, performance is even.Reinstall after the agent of clock hood type furnace finishing type can certainly be adopted to remove overvoltage stove sintering, can also complete in all-in-one oven forming agent remove with pre-burning after be cooled to room temperature, carry out some mechanical workouts after reinstall overvoltage stove sintering.Heat up at a slow speed and avoid product and remove at forming agent and crack with sintering process; Be incubated under final sintering temperature, pass into high-purity argon gas, ensure that product is sintered fully, surface reaches consistent with heart portion performance; Forming agent removes the stage and passes into hydrogen and avoid blank oxygenation in forming agent subtractive process; Occur that liquid phase stage furnace pressure≤0.8mbar avoids forming agent and removed rear blank top layer damage carbon, the vaporization losses that 40mbar argon gas avoids nickel phase in product is passed into after there is liquid phase, and pass into 50bar argon gas after reaching final sintering temperature and facilitate liquid phase flow in sintering process, improve product densification, hardness and intensity.

Adopt the alloy that preparation method of the present invention obtains, carbon gradient controls within 0.03%, and control accuracy is high, without sintering crack phenomenon, flexural deformation is little, and performance is even, Rockwell hardness >=87HRA, bending strength >=3000MPa, density 14.10 ~ 14.80g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%.

Embodiment

Embodiment 1: prepare substance 50Kg Wimet (external diameter 411mm), composition and weight percent are: nickel: 12%, chromium carbide: 1.2%, wolfram varbide: surplus.

The preparation of above-mentioned Wimet comprises the operations such as preparation of raw material, wet-milling, drying, compacting, sintering (following examples are same).Material composition and weight percent are: nickel powder: 12%, carbonization chromium powder 1.2%, tungsten carbide powder surplus.Take each raw material in proportion, add forming agent, by the compound of preparation in wet wheeling machine after ball milling, spraying dry, drying temperature is 90 ~ 100 DEG C, loads in dewaxing-sintering furnace after being then pressed into the pressed compact of specified dimension shape, passes into the hydrogen of dew point-60 DEG C, furnace temperature by room temperature to 550 DEG C, completed forming agent and removes in 40 ~ 45 hours; Then in 8 ~ 9 hours, be warming up to product again occur liquid phase, this stage furnace pressure≤0.8mbar; In stove, the high-purity argon gas of about 40mbar, volume percent >=99.99% is filled with again after there is liquid phase, within 1.5 ~ 2 hours, be warming up to final sintering temperature 1460 DEG C, be incubated the high-purity argon gas passing into 50bar, volume percent >=99.99% after 60 minutes again, continuation insulation cool to room temperature after 60 minutes.The alloy product performance of final acquisition: Rockwell hardness: 87.8HRA, bending strength 3120MPa, density 14.27g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%.

Embodiment 2: prepare substance 30Kg Wimet (external diameter 380mm), composition and weight percent are: nickel: 11%, chromium carbide: 0.75%, wolfram varbide: surplus.

Material composition and weight percent are: nickel powder: 11%, carbonization chromium powder: 0.75%, tungsten carbide powder: surplus.Take each raw material in proportion, add forming agent, by the compound for preparing in wet wheeling machine after ball milling, spraying dry, drying temperature is 90 ~ 100 DEG C, then load after being pressed into the pressed compact of specified dimension shape in dewaxing-sintering furnace, pass into the hydrogen of dew point-60 DEG C, furnace temperature in 35 ~ 40 hours by room temperature to 500 DEG C; Then in 8 ~ 9 hours, be warming up to product again occur liquid phase, this stage furnace pressure≤0.8mbar; In stove, the high-purity argon gas of about 40mbar, volume percent >=99.99% is filled with again after there is liquid phase, within 1.5 ~ 2 hours, be warming up to final sintering temperature 1460 DEG C, be incubated the high-purity argon gas passing into 50bar, volume percent >=99.99% after 50 minutes again, continuation insulation cool to room temperature after 40 minutes.The alloy product performance of final acquisition: Rockwell hardness: 88.4HRA, bending strength 3100MPa, density 14.36g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%.

Embodiment 3: prepare substance 10Kg Wimet (external diameter 212mm), composition and weight percent are: nickel: 10%, chromium carbide: 1.0%, wolfram varbide: surplus.

Material composition and weight percent are: nickel powder: 10%, carbonization chromium powder: 1.0%, tungsten carbide powder: surplus.Take each raw material in proportion, add forming agent, by the compound for preparing in wet wheeling machine after ball milling, spraying dry, drying temperature is 90 ~ 100 DEG C, loads in dewaxing-sintering furnace after being then pressed into the pressed compact of specified dimension shape, passes into the hydrogen of dew point-60 DEG C, furnace temperature by room temperature to 450 DEG C, completed forming agent and removes in 25 ~ 35 hours; Then in 7 ~ 8 hours, be warming up to product again occur liquid phase, this stage furnace pressure≤0.8mbar; In stove, the high-purity argon gas of about 40mbar, volume percent >=99.99% is filled with again after there is liquid phase, within 1 hour, be warming up to final sintering temperature 1480 DEG C, be incubated the high-purity argon gas passing into 50bar, volume percent >=99.99% after 30 minutes again, continuation insulation cool to room temperature after 30 minutes.The alloy product performance of final acquisition: Rockwell hardness: 89.5HRA, bending strength 3100MPa, density 14.53g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%

More than show and describe ultimate principle of the present invention and principal character and advantage of the present invention.The technician of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and specification sheets just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.Application claims protection domain is defined by appending claims and equivalent thereof.

Claims

1. a Wimet, is main ingredient with wolfram varbide, it is characterized in that: the composition of this alloy and weight percent are: nickel: 8% ~ 15% chromium carbide: 0.5% ~ 1.5% wolfram varbide: surplus.

2. Wimet according to claim 1, is characterized in that: the composition of this alloy and weight percent are: nickel: 10% ~ 12% chromium carbide: 0.5% ~ 1.0% wolfram varbide: surplus.

3. Wimet according to claim 1, is characterized in that: the composition of this alloy and weight percent are: nickel: 11% chromium carbide: 0.75% wolfram varbide: surplus.

4. the preparation method of the Wimet as described in one of claims 1 to 3, comprise the operations such as preparation of raw material, wet-milling, drying, compacting, sintering, it is characterized in that: material composition and weight percent are nickel powder 8% ~ 15%, carbonization chromium powder 0.5% ~ 1.5%, tungsten carbide powder surplus; Forming agent is added during preparation of raw material.

5. the preparation method of Wimet according to claim 4, is characterized in that: described drying process adopts spraying dry, and drying temperature is 90 ~ 100 DEG C.