阅读说明：本技术 一种高密度、高耐磨、高耐腐蚀性不锈钢材料及其生产方法 (High-density, high-wear-resistance and high-corrosion-resistance stainless steel material and production method thereof ) 是由 申承秀 王春官 盛德稳 于 2019-12-04 设计创作，主要内容包括：一种高密度、高耐磨、高耐腐蚀性不锈钢材料及其生产方法,涉及不锈钢材料的生产技术领域。先将Cr、Ni、Mo、Si和Fe元素混合,经雾化后进行球磨、过筛,取得不锈钢粉末,再将不锈钢粉末与C粉、润滑剂混合,经球磨,取得不锈钢材料混合粉,经模具中压制成形,取得不锈钢毛坯,再置于N<Sub>2</Sub>和H<Sub>2</Sub>的还原气氛中烧结,取得包括1.5%～2.5%的Si和0.5%～0.8%的C的不锈钢材料,且其硬度、强度、耐磨性、耐腐蚀性能大幅度提高。(A stainless steel material with high density, high wear resistance and high corrosion resistance and a production method thereof, relating to the stainless steel materialThe technical field of production. Mixing Cr, Ni, Mo, Si and Fe elements, atomizing, ball milling, sieving to obtain stainless steel powder, mixing the stainless steel powder with C powder and lubricant, ball milling to obtain mixed stainless steel powder, die pressing to obtain stainless steel blank, and setting in N 2 And H 2 The stainless steel material comprises 1.5 to 2.5 percent of Si and 0.5 to 0.8 percent of C, and the hardness, the strength, the wear resistance and the corrosion resistance of the stainless steel material are greatly improved.)

1. The stainless steel material with high density, high wear resistance and high corrosion resistance comprises, by weight, 16.0-18.0% of Cr, 10.0-14.0% of Ni, 2.0-3.0% of Mo and Fe, and trace impurity elements, and is characterized by also comprising 1.5-2.5% of Si and 0.5-0.8% of C.

2. The method for producing a high-density, high-wear-resistance, high-corrosion-resistance stainless steel material according to claim 1, characterized by comprising the steps of:

1) mixing Cr, Ni, Mo, Si and Fe elements, atomizing, ball-milling and sieving to obtain stainless steel powder;

2) mixing stainless steel powder, powder C and a lubricant, and performing ball milling to obtain stainless steel material mixed powder;

3) placing the stainless steel material mixed powder into a die for press forming to obtain a stainless steel blank;

4) placing stainless steel blanks in N₂And H₂Sintering in a reducing atmosphere to obtain a stainless steel material;

when the Cr, Ni, Mo, Si, C powder and Fe elements are mixed, the weight ratio of each element is Cr: 16.0% -18.0%, Ni: 10.0% -14.0%, Mo: 2.0% -3.0%, Si: 1.5% -2.5%, C: 0.5 to 0.8 percent of Fe and the balance of Fe.

3. The method for producing a high-density, high-wear-resistance and high-corrosion-resistance stainless steel material according to claim 2, wherein the grain size of the stainless steel powder is 45 to 110 μm.

4. The method for producing a high-density, high-wear-resistance and high-corrosion-resistance stainless steel material according to claim 2, wherein the grain size of the C powder is 30-45 μm.

5. The method for producing a high-density, high-wear-resistant, high-corrosion-resistant stainless steel material according to claim 2, characterized in that the lubricant constitutes 1.5% of the total weight of the stainless steel material powder mixture.

6. The method for producing a stainless steel material with high density, high wear resistance and high corrosion resistance according to claim 2 or 5, wherein in the step 2), a three-dimensional motion mixer is used for ball milling, the rotating speed is 12 r/min, and the time is 45 min.

7. The method for producing a high-density, high-wear-resistance and high-corrosion-resistance stainless steel material according to claim 2, wherein the pressing pressure in the step 3) is 600-700 MPa.

8. The method for producing a high-density, high-wear-resistant, high-corrosion-resistant stainless steel material according to claim 2, characterized in that the sintering is performed at a high temperature zone temperature of 1260 ℃.

Technical Field

The invention relates to the technical field of production of stainless steel materials.

Background

The powder metallurgy stainless steel is the stainless steel manufactured by a powder metallurgy method, has the advantages of reducing alloy element segregation, refining microstructure, improving performance, saving materials, saving energy consumption, reducing cost, and can be widely applied to the fields of automobiles, household appliances, medical appliances and the like. However, the powder metallurgy stainless steel powder has poor compressibility and is pressed at normal temperature, and the density of a green body after high-temperature sintering is only 6.8g/cm³The product has low density and poor wear resistance, and the application range of the powder metallurgy stainless steel is severely limited.

In order to expand the application field of the powder metallurgy stainless steel and promote the further development of the powder metallurgy stainless steel technology and the production process, the development of the method for leading the sintering density to reach 7.0g/cm is urgently needed³The stainless steel powder is applied to products with high density, strength, wear resistance and corrosion resistance, such as a methanol pump rotor in an automobile engine, medical instruments and the like.

Disclosure of Invention

In order to overcome the defects of the existing stainless steel material, the invention provides a stainless steel material with high density, high wear resistance and high corrosion resistance.

The stainless steel material with high density, high wear resistance and high corrosion resistance comprises, by weight, 16.0-18.0% of Cr, 10.0-14.0% of Ni, 2.0-3.0% of Mo, 1.5-2.5% of Si, 0.5-0.8% of C, Fe and trace impurity elements.

Researches show that the elastic limit, yield point and tensile strength of the stainless steel material can be obviously improved due to the addition of silicon, and simultaneously, the combination of silicon, molybdenum, chromium and the like has the effects of improving corrosion resistance and oxidation resistance, promoting the densification of a matrix, effectively improving the density of a product and enabling the density of the stainless steel material product to reach 7.3g/cm³The hardness, strength, wear resistance and corrosion resistance are greatly improved.

Another object of the present invention is to propose a method for producing the above stainless steel material.

The invention comprises the following steps:

1) mixing Cr, Ni, Mo, Si and Fe elements, atomizing, ball-milling and sieving to obtain stainless steel powder;

2) mixing stainless steel powder, powder C and a lubricant, and performing ball milling to obtain stainless steel material mixed powder;

3) placing the stainless steel material mixed powder into a die for press forming to obtain a stainless steel blank;

4) placing stainless steel blanks in N₂And H₂Sintering in a reducing atmosphere to obtain a stainless steel material;

when the Cr, Ni, Mo, Si, C powder and Fe elements are mixed, the weight ratio of each element is Cr: 16.0% -18.0%, Ni: 10.0% -14.0%, Mo: 2.0% -3.0%, Si: 1.5% -2.5%, C: 0.5 to 0.8 percent of Fe and the balance of Fe.

By the method, the silicon powder and other elements are directly atomized after being mixed, so that the mixing uniformity of the silicon powder and other elements is ensured, and segregation is reduced. Because of the addition of the silicon powder, the shrinkage of a sintered product is large, and the powder prepared by adopting a direct atomization mode can ensure the size consistency and the performance uniformity of the sintered product. The push-down stainless steel special sintering furnace is adopted for sintering under ammonia decomposition atmosphere, so that the sintering production efficiency is effectively improved, and the hardness and the wear resistance of the stainless steel product are greatly improved by a nitrided layer formed on the surface of the product.

Furthermore, the particle size of the stainless steel powder is 45-110 μm. The stainless steel powder with different meshes can be mixed according to a certain proportion, and the density and the strength of a green body can be improved.

The grain size of the C powder is 30-45 mu m, and the C powder with small grain size can effectively promote the alloying of a matrix during sintering and improve the hardness and strength of a sintered product.

The lubricant accounts for 1.5 percent of the total weight of the stainless steel material mixed powder. The purpose of adding 1.5% of lubricant is: the powder metallurgy stainless steel powder has poor compressibility and is very easy to damage a die to form phenomena such as galling, and through full tests and verification, 1.5 percent of lubricant can reduce the damage to the die during pressing and can ensure the strength of a green body and the degreasing effect of sintering.

And in the step 2), a three-dimensional motion mixer is adopted for ball milling, the rotating speed is 12 revolutions per minute, and the time is 45 minutes. The uniformity of the mixed powder is ensured, and segregation is reduced.

The pressing pressure in the step 3) is 600-700 MPa, so that the pressing density of the stainless steel blank can reach 6.45-6.55 g/cm³And good basic conditions are provided for further improving the density in the later period.

In addition, sintering was carried out at a high temperature region of 1260 ℃. The density of the sintered body reaches 7.3g/cm through testing³Above, the hardness exceeds 85 HRB.

Detailed Description

Firstly, material preparation: the following four powder materials (see the following table) are prepared by adopting 316L and 316L added with silicon powder as base powder and then adding carbon powder and lubricant according to the following formula

Code number	Cr	Ni	Mo	Si	C	Lubricant agent	Fe
								316L(B)	17.0%	12.0%	2.5%	2%	0.7%	1.5%	Balance of
316L	17.0%	12.0%	2.5%	/	/	1.5%	Balance of
								316L(C)	17.0%	12.0%	2.5%	2%	/	1.5%	Balance of
316L(D)	17.0%	12.0%	2.5%	/	0.7%	1.5%	Balance of

In addition, the particle size of the C powder is 30-45 μm.

Secondly, the production is carried out according to the proportion, and the process is as follows:

1. milling:

mixing Cr, Ni, Mo, Si and Fe elements, atomizing, ball milling, and sieving with a 60-mesh sieve to obtain stainless steel powder.

The detection shows that the particle size of the stainless steel powder is 45-110 mu m.

2. Mixing:

adding a lubricant and carbon powder into stainless steel powder, and ball-milling and mixing by adopting a three-dimensional motion mixer at the rotating speed of 12 r/min for 45 min to obtain the stainless steel material mixed powder.

3. Pressing and forming:

and placing the stainless steel material mixed powder into a die for press forming to obtain a stainless steel blank.

And selecting a mechanical press with higher pressing precision, wherein the pressure is 600-700 MPa.

The detection shows that the pressing density of the stainless steel blank is 6.45-6.55 g/cm³。

4. And (3) sintering:

the sintering treatment is a heat treatment performed at the melting point temperature of the main element.

The stainless steel blank formed by pressing passes through a push rod type stainless steel sintering furnace in the presence of N₂And H₂In a reducing atmosphere at a high temperature of 1260 ℃, to obtain a sintered body.

The density of the sintered body reaches 7.3g/cm through testing³Above, the hardness exceeds 85 HRB.

5. Shaping:

after the sintered body is deburred, press-shaping is performed using a press die so as to have a predetermined shape and a predetermined dimensional accuracy.

And thirdly, verifying the performance of the automobile methanol pump rotor manufactured by the powder metallurgy method and the method.

The methanol pump rotor is a key part of an automobile methanol pump, methanol is conveyed by the methanol pump, the methanol is a product of coal chemical industry, and can replace gasoline to be used as the output power of the automobile. However, since methanol has high corrosiveness, electrical conductivity, permeability and poor lubricity, and has high electrolytic capacity when electricity is applied, high requirements are made on the hardness, strength and corrosion resistance of a powder metallurgy stainless steel pump rotor as a core component.

The powder metallurgy method is adopted to manufacture the methanol pump rotor for the automobile by 316L stainless steel powder.

The method for manufacturing the methanol pump rotor for the automobile adds silicon powder and carbon powder into 316L stainless steel powder to form a new material 316L (B), so that the sintering density of the new material can reach 7.3g/cm³The hardness, strength, wear resistance and corrosion resistance are greatly improved.

The following is a table comparing the hardness, density, wear resistance, corrosion resistance test results for 316L and new materials 316L (b), 316L (c), 316L (d):

the test data of the above four material tests show that the products made of the common materials 316L, (C) and 316L (D) have abrasion after 1000 hours of operation, have a large difference with the use requirement (bench test time: 4000 hours), and cannot meet the use requirement. The new material product 316L (B) added with silicon and carbon has various performances far exceeding those of other three materials, reaches the design requirements, and meets the use requirements through user tests.