CN106319318A

CN106319318A - Hard alloy

Info

Publication number: CN106319318A
Application number: CN201510357715.7A
Authority: CN
Inventors: 姜蕾
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-06-26
Filing date: 2015-06-26
Publication date: 2017-01-11

Abstract

The invention provides a hard alloy comprising the components by the weight percentage: 6%-18% of nickel, 0.5%-1.5% of chromium carbide, and the balance tungsten carbide; the hard alloy has the advantages of simple components, high hardness, good abrasion resistance, and strong corrosion resistance. A preparation method comprises the steps of raw material preparation, wet grinding, drying, pressing, sintering and the like and comprises the steps: taking the raw material ingredients by the weight percentage: 8%-15% of a nickel powder, 0.5%-1.5% of a chromium carbide powder, and the balance tungsten carbide; during batching, adding a forming agent; carrying out 90-100 DEG C atomizing drying; carrying out dewaxing and sintering integrated process, making a furnace temperature rise to 450 DEG C-550 DEG C within 25-45 h, and completing removal of the forming agent; and then heating within 7-9 hours until the product generates a liquid phase, then introducing high-pure argon gas into a furnace, heating to a final sintering temperature of 1460-1480 DEG C within 1-2 h, carrying out heat preservation for 30-60 minutes and then introducing high-pure argon gas, continuing to carry out heat preservation for 30-60 min, and then cooling. The preparation method not only can prepare general specification alloys, and also can satisfy large alloy preparation and performance requirements.

Description

A kind of hard alloy

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

Hard alloy has obvious advantage at aspects such as the mold for forming of Powder Metallurgy Industry ferromagnetism powder, sealing rings, not only has the highest hardness and a wearability, and sticking to mould when can avoid ferromagnetism powder compacting, improve the resistance to corrosion of sealing ring.In existing alloy manufacturing methods, by adding multiple element, putting forward heavy alloyed hardness and intensity by subzero treatment, Ageing Treatment, but the effect that hard alloy carries out the mode such as deep cooling, Ageing Treatment there is also dispute, the product that substance is bigger is also unsuitable for or effect is difficult to detect.Chinese patent application " a kind of hard alloy containing vanadium and preparation method " (200810031230.9), simultaneously containing 0.5～the VC of the Cr3C2 of 3.0% and 0.3～2.5% in alloy, use vacuum drying, sintering temperature 1430～1460 DEG C, temperature retention time 30～60 minutes, and it is filled with 3～5MPa(equal to 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 bigger, the concordance of material and the uniformity of green density are difficult to ensure that, easily there is crackle, flexural deformation in particularly massive article (substance >=10Kg or diameter >=150mm), it is impossible to ensure densification and the uniformity of performance of massive article.

Summary of the invention

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

The hard alloy of the present invention, with tungsten carbide as key component, its composition and percentage by weight be:

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

As improvement, the composition of this alloy and percentage by weight it is: nickel: 8%～15% chromium carbide: 0.5%～1.0% tungsten carbide: surplus.

As improving further, the composition of this alloy and percentage by weight be: nickel: 11% chromium carbide: 0.75% tungsten carbide: surplus.

The preparation method of the hard alloy of the present invention, including preparation of raw material, wet grinding, be dried, suppress, operation, material composition and the percentage by weight such as sintering are nikel 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 uses and is spray-dried, and baking temperature is 90～100 DEG C.

Sintering uses dewaxing and sintering integrated metallization processes, and furnace temperature was warming up to 450 DEG C～550 DEG C in 25～45 hours, completes forming agent removing, and is passed through the hydrogen of dew point-60 DEG C；Then in 7～9 hours, it is warming up to product again liquid phase occurs, this stage furnace pressure≤0.8mbar；Occur being filled with in stove again after liquid phase 40～80mbar, the high-purity argon gas of percent by volume >=99.99%, within 1～2 hour, it is warming up to final sintering temperature 1460～1480 DEG C, it is passed through the high-purity argon gas of 50bar, percent by volume >=99.99% after being incubated 30～60 minutes again, cools down after continuing insulation 30～60 minutes.

Except hard phase tungsten carbide, Binder Phase nickel, raw material only with the addition of Cr3C2, and Cr3C2 alloy bonding mutually in dissolve each other in a large number, unrelated with carbon content height, therefore in alloy, carbon content control is easier to, it is ensured that performance and size and precision, its dosage is relatively low simultaneously, does not affect intensity and the porosity of alloy.Use enclosed spray drying farthest to avoid impurity and enter material, improve stability and the concordance of material, it is ensured that suppress the uniform of the most even green density of fashion material simultaneously.Utilizing dewaxing-sintering furnace, use dewaxing and sintering integrated metallization processes, it is ensured that the uniform removing of forming agent, farthest improve control accuracy and the uniformity of carbon content, the flexural deformation making product is little, and performance is uniform.Can certainly use clock hood type furnace finishing type agent removing after reinstall overvoltage stove sintering, it is also possible to complete in all-in-one oven forming agent removing and pre-burning after be cooled to room temperature, carry out some machinings after reinstall overvoltage stove sintering.At a slow speed heat up avoid product forming agent removing and sintering process crack；It is incubated under final sintering temperature, is passed through high-purity argon gas, it is ensured that product is sufficiently sintered, and surface reaches consistent with heart portion performance；The forming agent removing stage is passed through hydrogen and avoids blank oxygen supplement 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, it is passed through 40mbar argon after liquid phase occurs and avoids the evaporation loss of nickel phase in product, and after reaching final sintering temperature, it is passed through the liquid phase flowing that 50bar argon promotes in sintering process, improve product densification, hardness and intensity.

Using the alloy that the 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 uniform, Rockwell hardness >=87HRA, bending strength >=3000MPa, density 14.10～14.80 g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%.

Detailed description of the invention

Embodiment 1: prepare substance 50Kg hard alloy (external diameter 411mm), composition and percentage by weight be: nickel: 12%, chromium carbide: 1.2%, tungsten carbide: surplus.

The preparation of above-mentioned hard alloy include preparation of raw material, wet grinding, be dried, suppress, the operation such as sintering (following example with).Material composition and percentage by weight be: nikel powder: 12%, carbonization chromium powder 1.2%, tungsten carbide powder surplus.Weigh each raw material in proportion, add forming agent, by the compound of preparation in wet milk after ball milling, it is spray-dried, baking temperature is 90～100 DEG C, loads in dewaxing-sintering furnace, be passed through the hydrogen of dew point-60 DEG C after being then pressed into the pressed compact of given size shape, furnace temperature by room temperature to 550 DEG C, completed forming agent removing in 40～45 hours；Then in 8～9 hours, it is warming up to product again liquid phase occurs, this stage furnace pressure≤0.8mbar；In stove, the high-purity argon gas of about 40mbar, percent by volume >=99.99% it is filled with again after liquid phase occurs, within 1.5～2 hours, it is warming up to final sintering temperature 1460 DEG C, it is passed through the high-purity argon gas of 50bar, percent by volume >=99.99% after being incubated 60 minutes again, after continuing insulation 60 minutes, is cooled to room temperature.The final alloy product performance obtained: Rockwell hardness: 87.8HRA, bending strength 3120MPa, density 14.27 g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%.

Embodiment 2: prepare substance 30Kg hard alloy (external diameter 380mm), composition and percentage by weight be: nickel: 11%, chromium carbide: 0.75%, tungsten carbide: surplus.

Material composition and percentage by weight be: nikel powder: 11%, carbonization chromium powder: 0.75%, tungsten carbide powder: surplus.Weigh each raw material in proportion, add forming agent, by the compound for preparing in wet milk after ball milling, it is spray-dried, baking temperature is 90～100 DEG C, be then pressed into after the pressed compact of given size shape loading in dewaxing-sintering furnace, be passed through 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, it is warming up to product again liquid phase occurs, this stage furnace pressure≤0.8mbar；In stove, the high-purity argon gas of about 40mbar, percent by volume >=99.99% it is filled with again after liquid phase occurs, within 1.5～2 hours, it is warming up to final sintering temperature 1460 DEG C, it is passed through the high-purity argon gas of 50bar, percent by volume >=99.99% after being incubated 50 minutes again, after continuing insulation 40 minutes, is cooled to room temperature.The final alloy product performance obtained: Rockwell hardness: 88.4HRA, bending strength 3100MPa, density 14.36 g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%.

Embodiment 3: prepare substance 10Kg hard alloy (external diameter 212mm), composition and percentage by weight be: nickel: 10%, chromium carbide: 1.0%, tungsten carbide: surplus.

Material composition and percentage by weight be: nikel powder: 10%, carbonization chromium powder: 1.0%, tungsten carbide powder: surplus.Weigh each raw material in proportion, add forming agent, by the compound for preparing in wet milk after ball milling, it is spray-dried, baking temperature is 90～100 DEG C, loads in dewaxing-sintering furnace, be passed through the hydrogen of dew point-60 DEG C after being then pressed into the pressed compact of given size shape, furnace temperature by room temperature to 450 DEG C, completed forming agent removing in 25～35 hours；Then in 7～8 hours, it is warming up to product again liquid phase occurs, this stage furnace pressure≤0.8mbar；In stove, the high-purity argon gas of about 40mbar, percent by volume >=99.99% it is filled with again after liquid phase occurs, within 1 hour, it is warming up to final sintering temperature 1480 DEG C, it is passed through the high-purity argon gas of 50bar, percent by volume >=99.99% after being incubated 30 minutes again, after continuing insulation 30 minutes, is cooled to room temperature.The final alloy product performance obtained: Rockwell hardness: 89.5HRA, bending strength 3100MPa, density 14.53 g/cm3, magnetic force 0KA/m, cobalt magnetic≤0.1%

The ultimate principle of the present invention and principal character and advantages of the present invention have more than been shown and described.Skilled person will appreciate that of the industry; the present invention is not restricted to the described embodiments; the principle that the present invention is simply described described in above-described embodiment and description; 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 both fall within scope of the claimed invention.Claimed scope is defined by appending claims and equivalent thereof.

Claims

1. a hard alloy, with tungsten carbide as key component, it is characterised in that: the composition of this alloy and percentage by weight be: nickel: 8%～15% chromium carbide: 0.5%～1.5% tungsten carbide: surplus.

Hard alloy the most according to claim 1, it is characterised in that: the composition of this alloy and percentage by weight be: nickel: 10%～12% chromium carbide: 0.5%～1.0% tungsten carbide: surplus.

Hard alloy the most according to claim 1, it is characterised in that: the composition of this alloy and percentage by weight be: nickel: 11% chromium carbide: 0.75% tungsten carbide: surplus.

4. the preparation method of the hard alloy as described in one of claims 1 to 3, including preparation of raw material, wet grinding, be dried, suppress, the operation such as sintering, it is characterized in that: material composition and percentage by weight are nikel powder 8%～15%, carbonization chromium powder 0.5%～1.5%, tungsten carbide powder surplus；Forming agent is added during preparation of raw material.

The preparation method of hard alloy the most according to claim 4, it is characterised in that: described drying process uses and is spray-dried, and baking temperature is 90～100 DEG C.