阅读说明：本技术 一种抗热裂混晶硬质合金及其制备方法 (Thermal cracking resistant mixed crystal hard alloy and preparation method thereof ) 是由 叶惠明 叶少良 诸优明 叶戈 刘文辉 于 2020-07-21 设计创作，主要内容包括：一种抗热裂混晶硬质合金及其制备方法,由以下按照重量份数计的组分构成：复合硬质相：10～24份粒径为0.4～0.8μm的WC和25～45份粒径为1.0～2.5μm的WC；粘结相：10～14份；耐腐蚀添加剂：0.05～0.3份的Re；碳化铬粉：0.8～1.5份,稀土氧化物粉：0.15～0.5份；抑制剂：0.1～0.5份的Ta。本发明强度高、硬度高,抗热裂性能好,可在热机械腐蚀疲劳的环境下使用。(The thermal cracking resistant mixed crystal hard alloy and the preparation method thereof are composed of the following components in parts by weight: composite hard phase: 10-24 parts of WC with the particle size of 0.4-0.8 mu m and 25-45 parts of WC with the particle size of 1.0-2.5 mu m; a binding phase: 10-14 parts; corrosion-resistant additive: 0.05-0.3 part of Re; chromium carbide powder: 0.8-1.5 parts of rare earth oxide powder: 0.15-0.5 part; inhibitor (B): 0.1 to 0.5 parts of Ta. The invention has high strength, high hardness and good thermal cracking resistance, and can be used in the environment of thermomechanical corrosion fatigue.)

1. The thermal cracking resistant mixed crystal hard alloy is characterized by comprising the following components in parts by weight:

composite hard phase: 10-24 parts of WC with the particle size of 0.4-0.8 mu m and 25-45 parts of WC with the particle size of 1.0-2.5 mu m;

a binding phase: 10-14 parts;

corrosion-resistant additive: 0.05-0.3 part of Re;

chromium carbide powder: 0.8 to 1.5 parts of,

rare earth oxide powder: 0.15-0.5 part;

inhibitor (B): 0.1 to 0.5 parts of Ta.

2. The hot crack resistant mixed crystal cemented carbide of claim 1, wherein the binder phase is Co.

3. The hot crack resistant mixed crystal cemented carbide of claim 1, wherein the binder phase is Ni.

4. The hot crack resistant mixed crystal cemented carbide according to claim 1, wherein the binder phase is a mixture of Co and Ni, preferably in a mass ratio of 1-3: 1.

5. The hot crack resistant mixed crystal cemented carbide of claim 1, wherein the rare earth oxide powder is cerium oxide.

6. A method of producing a hot-crack resistant mixed-crystal cemented carbide according to any one of claims 1-5, characterised in that the method comprises the steps of:

mixing WC powder, Co powder, a corrosion-resistant additive, chromium carbide powder, rare earth oxide powder and an inhibitor according to a set raw material proportion, uniformly mixing the mixture in a ball mill, and adding a forming agent for forming to obtain a mixture;

cooling and pressing the mixture into a vacuum furnace, wherein the heating rate is 4-10 ℃/min, the reaction temperature is 1050-1150 ℃, and the heat preservation time is 3-4 hours to obtain a billet;

putting the briquettes into the ball mill again for ball milling and crushing, and then carrying out compression molding;

sintering and cooling to obtain the finished hard alloy.

7. The method for preparing the thermal crack-resistant mixed crystal cemented carbide as claimed in claim 6, wherein the forming agent is paraffin wax.

8. The method of claim 7, wherein the ball milling time is maintained between 18 and 32 hours during the processing in the ball mill.

9. The method for preparing the thermal crack resistant mixed crystal hard alloy as claimed in claim 8, wherein the temperature is maintained at 1350-.

Technical Field

The invention belongs to the field of alloy processing, and particularly relates to a thermal cracking resistant mixed crystal hard alloy and a preparation method thereof.

Background

Generally, the toughness and the wear resistance of the hard alloy are in contradiction, and the strength and the hardness are conventional detection indexes. The fine particle and ultrafine particle alloy can obtain high strength and high hardness at the same time, but the toughness is poor; coarse grain, high binder phase alloys have better toughness, but their strength generally decreases with decreasing hardness. In the conventional method, longer ball milling time is adopted, but the grain size of the alloy is reduced, so that the toughness of the alloy is reduced, the thermal conductivity is reduced, and the early failure of the product is easily caused by poor thermal fatigue resistance of the hard alloy used under the conditions of high temperature and large cyclic stress.

The traditional method for preparing the mixed crystal hard alloy is mainly that submicron-scale WC powder, micron-scale WC powder and Co powder are mixed in a ball milling way according to a certain proportion, and then the mixture is sintered to obtain a hard alloy block body with a double-crystal structure; or adding tabular crystal W powder into mixed powder of WC and Co to obtain WC-Co hard alloy with a bicrystal structure in the sintered alloy. The preparation methods generally have the defects that the quantity and the size of coarse WC are difficult to control, the volume fraction of coarse grains is small, and the like, so that the transverse rupture strength and the rupture toughness of the hard alloy block cannot be satisfactorily matched, and the preparation process is complicated and the quality is difficult to control.

Disclosure of Invention

The technical problem to be solved by the invention is to provide

In order to solve the technical problems, the invention adopts the following technical scheme:

the thermal cracking resistant mixed crystal hard alloy is characterized by comprising the following components in parts by weight:

composite hard phase: 10-24 parts of WC with the particle size of 0.4-0.8 mu m and 25-45 parts of WC with the particle size of 1.0-2.5 mu m;

a binding phase: 10-14 parts;

corrosion-resistant additive: 0.05-0.3 part of Re;

chromium carbide powder: 0.8 to 1.5 parts of,

rare earth oxide powder: 0.15-0.5 part;

inhibitor (B): 0.1 to 0.5 parts of Ta.

The binder phase is Co.

The binder phase is Ni.

The binding phase is a mixture of Co and Ni, and the mass ratio of Co to Ni is preferably 1-3: 1.

The rare earth oxide powder is cerium oxide.

A preparation method of a hot-cracking-resistant mixed crystal hard alloy is characterized by comprising the following steps:

mixing WC powder, Co powder, a corrosion-resistant additive, chromium carbide powder, rare earth oxide powder and an inhibitor according to a set raw material proportion, uniformly mixing the mixture in a ball mill, and adding a forming agent for forming to obtain a mixture;

cooling and pressing the mixture into a vacuum furnace, wherein the heating rate is 4-10 ℃/min, the reaction temperature is 1050-1150 ℃, and the heat preservation time is 3-4 hours to obtain a billet;

putting the briquettes into the ball mill again for ball milling and crushing, and then carrying out compression molding;

sintering and cooling to obtain the finished hard alloy.

The forming agent is paraffin.

When the ball mill is used for treatment, the ball milling time is maintained at 18-32 hours.

During the sintering, the temperature is kept at 1350 ℃ and 1450 ℃, and the holding time is 6-8 hours.

The hard alloy prepared by the invention has high strength, high hardness and good thermal cracking resistance, and can be used in the environment of thermal mechanical corrosion fatigue.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments in order to further understand the features and technical means of the invention and achieve specific objects and functions.