阅读说明：本技术 一种低铬合金磨球及其加工工艺 (Low-chromium alloy grinding ball and processing technology thereof ) 是由 蔡发华 于 2019-09-29 设计创作，主要内容包括：本发明提供一种低铬合金磨球及其加工工艺,涉及低铬合金技术领域,按质量百分含量计,其化学成分为：C 3.2-4.1％、Cr 1.5-2.6％、Mn 0.3-0.8％、Si 0.4-0.9％、Ni 2.5-5.4％、B 0.78-1.06％、Mo 0.08-0.21％、Ta 0.004-0.009％、Zn 0.36-0.61％、Nb 0.11-0.56％、W 0.007-0.012％、V 0.02-0.05％、P<0.02％、S<0.02％,余量为Fe及不可避免的杂志。本发明通过熔炼、变质处理、浇注、热处理制得的磨球具有良好的抗冲击性能和耐磨性能,以及较高的硬度。(The invention provides a low-chromium alloy grinding ball and a processing technology thereof, relating to the technical field of low-chromium alloy, wherein the grinding ball comprises the following chemical components in percentage by mass: 3.2 to 4.1 percent of C, 1.5 to 2.6 percent of Cr, 0.3 to 0.8 percent of Mn, 0.4 to 0.9 percent of Si, 2.5 to 5.4 percent of Ni, 0.78 to 1.06 percent of B, 0.08 to 0.21 percent of Mo, 0.004 to 0.009 percent of Ta, 0.36 to 0.61 percent of Zn, 0.11 to 0.56 percent of Nb, 0.007 to 0.012 percent of W, 0.02 to 0.05 percent of V, 0.02 percent of P, 0.02 percent of S, and the balance of Fe and inevitable impurities. The grinding ball prepared by smelting, modification, casting and heat treatment has good impact resistance and wear resistance and higher hardness.)

1. The low-chromium alloy grinding ball is characterized by comprising the following chemical components in percentage by mass: 3.2 to 4.1 percent of C, 1.5 to 2.6 percent of Cr, 0.3 to 0.8 percent of Mn, 0.4 to 0.9 percent of Si, 2.5 to 5.4 percent of Ni, 0.78 to 1.06 percent of B, 0.08 to 0.21 percent of Mo, 0.004 to 0.009 percent of Ta, 0.36 to 0.61 percent of Zn, 0.11 to 0.56 percent of Nb, 0.007 to 0.012 percent of W, 0.02 to 0.05 percent of V, 0.02 percent of P, 0.02 percent of S, and the balance of Fe and inevitable impurities.

2. The low chromium alloy grinding ball according to claim 1, wherein the chemical composition comprises, in mass percent: 3.5 to 3.8 percent of C, 1.8 to 2.4 percent of Cr, 0.5 to 0.7 percent of Mn, 0.5 to 0.7 percent of Si, 3.2 to 4.1 percent of Ni, 0.88 to 0.93 percent of B, 0.12 to 0.16 percent of Mo, 0.005 to 0.007 percent of Ta, 0.44 to 0.53 percent of Zn, 0.28 to 0.36 percent of Nb, 0.009 to 0.011 percent of W, 0.03 to 0.04 percent of V, 0.02 percent of P, 0.02 percent of S, and the balance of Fe and inevitable impurities.

3. The low chromium alloy grinding ball according to claim 2, wherein the chemical composition comprises, in mass percent: 3.6% of C, 2.1% of Cr, 0.6% of Mn, 0.6% of Si, 3.5% of Ni, 0.92% of B, 0.14% of Mo, 0.006% of Ta, 0.46% of Zn0.32% of Nb, 0.01% of W, 0.04% of V, 0.02% of P, 0.02% of S, and the balance of Fe and inevitable impurities.

4. A process for manufacturing a low chromium alloy grinding ball according to any one of claims 1 to 3, comprising the steps of:

1) smelting: the raw materials calculated according to the proportion are put into a medium-frequency induction control furnace for smelting, the smelting temperature is 1540-1580 ℃, after the raw materials are completely molten, a slag skimming agent and a slag remover prepared from silicon, calcium and aluminum in a mass ratio of 1: 2: 1, removing impurities such as oxygen, phosphorus, sulfur and the like in the alloy liquid, and controlling the tapping temperature to 1570-;

2) modification treatment: crushing yttrium-based rare earth to the particle size of 1-3mm, drying at about 200-;

3) pouring: pouring the alloy liquid subjected to modification treatment at 1460-1490 ℃ to obtain a primary grinding ball;

4) and (3) heat treatment: and sequentially carrying out primary quenching, tempering, laser melting and laser quenching processes on the primary grinding ball to obtain the low-chromium alloy grinding ball.

5. The processing technology of the low-chromium alloy grinding ball as claimed in claim 4, wherein the primary quenching technology in the step 4) is specifically as follows: the temperature of the grinding ball is raised to 810-880 ℃ at the temperature rising rate of 160 ℃/h of 140-.

6. The processing technology of the low-chromium alloy grinding ball as claimed in claim 4, wherein the tempering technology in the step 4) is specifically as follows: raising the temperature of the grinding ball subjected to primary quenching treatment to 405-420 ℃ at the heating rate of 40-60 ℃/h, preserving the temperature for 6-8h, and naturally cooling to room temperature.

7. The process for machining a low-chromium alloy grinding ball according to claim 4, wherein the laser fusing process in the step 4) is specifically as follows: and carrying out laser fusion treatment on the surface of the grinding ball by adopting laser under an argon atmosphere, wherein the peak power of the square wave is 800-1200W, the pulse frequency is 80-120HZ, the duty ratio is 0.4-0.7, the average laser power is 800-1000W, and the scanning speed is 11-13 mm/s.

8. The processing technology of the low-chromium alloy grinding ball according to claim 4, wherein the laser quenching technology in the step 4) is specifically as follows: and performing laser quenching treatment on the surface of the grinding ball by adopting laser, wherein the laser power is 700-800W, the scanning speed is 25-35mm/s, the focal length is 320-340mm, and the defocusing amount is 35-45 mm.

Technical Field

The invention relates to the technical field of low-chromium alloy, in particular to a low-chromium alloy grinding ball and a processing technology thereof.

Background

The wear-resistant ball is a grinding medium widely applied to ball mills in the industries of metallurgical mines, cement building materials, thermal power generation, flue gas desulfurization, magnetic materials, chemical engineering, coal water slurry, pellet ore, slag, ultrafine powder, fly ash, calcium carbonate, quartz sand and the like, and is used for grinding materials in the ball mills, wherein one of the grinding media is white cast iron which takes chromium as a main alloy element and is called chromium alloy cast iron for short, and a casting grinding ball which takes the chromium alloy cast iron as a material is called chromium alloy cast iron grinding ball. The structure of the common white cast iron is ledeburite, and the common white cast iron has the characteristics of poor toughness, large brittleness, poor wear resistance and the like, and the function of chromium in the white cast iron can be embodied in the following two aspects: promote the formation of carbide, change the structure, performance and form of the carbide; solid solution in austenite changes the phase change property of austenite. According to the difference of chromium content, the chromium white cast iron is classified into low-chromium white cast iron, medium-chromium white cast iron, and high-chromium white cast iron.

The low-chromium white cast iron has the structure that the carbide is M₃The C-type carbide basically keeps the network structure of cementite in the Fe-C alloy. The matrix structure of the low-chromium white cast iron in an as-cast state is coarse pearlite and has the characteristics of low hardness, poor toughness and no wear resistance, so that the wear-resistant ball has good impact resistance and wear resistance by adjusting the element formula in the wear-resistant ball according to the actual requirement of the wear-resistant ball and assisting a specific processing technology, a heat treatment technology and the like, and the technical problem to be solved at present in the field of high hardness is the technical problem to be solved urgently.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a low-chromium alloy grinding ball and a processing technology thereof, so that the wear-resistant ball has good impact resistance and wear resistance and higher hardness.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

the low-chromium alloy grinding ball comprises the following chemical components in percentage by mass: 3.2 to 4.1 percent of C, 1.5 to 2.6 percent of Cr, 0.3 to 0.8 percent of Mn, 0.4 to 0.9 percent of Si, 2.5 to 5.4 percent of Ni, 0.78 to 1.06 percent of B, 0.08 to 0.21 percent of Mo, 0.004 to 0.009 percent of Ta0.004 to 0.009 percent of Zn, 0.36 to 0.61 percent of Nb, 0.11 to 0.56 percent of Nb, 0.007 to 0.012 percent of W, 0.02 to 0.05 percent of V, 0.02 percent of P, 0.02 percent of S, and the balance of Fe and inevitable impurities.

Preferably, the chemical components are as follows by mass percent: 3.5 to 3.8 percent of C, 1.8 to 2.4 percent of Cr, 0.5 to 0.7 percent of Mn, 0.5 to 0.7 percent of Si, 3.2 to 4.1 percent of Ni, 0.88 to 0.93 percent of B, 0.12 to 0.16 percent of Mo, 0.005 to 0.007 percent of Ta, 0.44 to 0.53 percent of Zn, 0.28 to 0.36 percent of Nb, 0.009 to 0.011 percent of W, 0.03 to 0.04 percent of V, 0.02 percent of P, 0.02 percent of S, and the balance of Fe and inevitable impurities.

Preferably, the chemical components are as follows by mass percent: 3.6% of C, 2.1% of Cr, 0.6% of Mn, 0.6% of Si, 3.5% of Ni, 0.92% of B, 0.14% of Mo, 0.006% of Ta, 0.46% of Zn, 0.32% of Nb, 0.01% of W, 0.04% of V, less than 0.02% of P, less than 0.02% of S, and the balance of Fe and inevitable impurities.

The processing technology of the low-chromium alloy grinding ball comprises the following steps:

1) smelting: the raw materials calculated according to the proportion are put into a medium-frequency induction control furnace for smelting, the smelting temperature is 1540-1580 ℃, after the raw materials are completely molten, a slag skimming agent and a slag remover prepared from silicon, calcium and aluminum in a mass ratio of 1: 2: 1, removing impurities such as oxygen, phosphorus, sulfur and the like in the alloy liquid, and controlling the tapping temperature to 1570-;

2) modification treatment: crushing yttrium-based rare earth to the particle size of 1-3mm, drying at about 200-;

3) pouring: pouring the alloy liquid subjected to modification treatment at 1460-1490 ℃ to obtain a primary grinding ball;

4) and (3) heat treatment: and sequentially carrying out primary quenching, tempering, laser melting and laser quenching processes on the primary grinding ball to obtain the low-chromium alloy grinding ball.

Further, the primary quenching process specifically comprises the following steps: the temperature of the grinding ball is raised to 810-880 ℃ at the temperature rising rate of 160 ℃/h of 140-.

Further, the tempering process specifically comprises the following steps: raising the temperature of the grinding ball subjected to primary quenching treatment to 405-420 ℃ at the heating rate of 40-60 ℃/h, preserving the temperature for 6-8h, and naturally cooling to room temperature.

Further, the laser fusing process specifically comprises the following steps: and carrying out laser fusion treatment on the surface of the grinding ball by adopting laser under an argon atmosphere, wherein the peak power of the square wave is 800-1200W, the pulse frequency is 80-120HZ, the duty ratio is 0.4-0.7, the average laser power is 800-1000W, and the scanning speed is 11-13 mm/s.

Further, the laser quenching process specifically comprises the following steps: and performing laser quenching treatment on the surface of the grinding ball by adopting laser, wherein the laser power is 700-800W, the scanning speed is 25-35mm/s, the focal length is 320-340mm, and the defocusing amount is 35-45 mm.

(III) advantageous effects

The invention provides a low-chromium alloy grinding ball and a processing technology thereof, firstly, the component formula of the grinding ball is optimized, and elements such as manganese, silicon, nickel, boron, molybdenum and the like are combined in proper amount and are cooperated with each other, so that the grain boundary can be purified, the grains can be refined, the carbide content can be controlled and the like, and the grinding ball has excellent hardness, toughness and wear resistance. Meanwhile, in the heat treatment process, an oil quenching mode is selected to be more favorable for improving the wear resistance of the magic ball, the grinding ball is subjected to primary quenching and tempering treatment by selecting proper temperature rise rate, quenching temperature and tempering temperature, so that the metallographic structure in the grinding ball is uniform, and after the grinding ball is treated by the laser melting and laser quenching process, the quenching layer of the grinding ball is fine acicular martensite, so that the quenching layer has high hardness and good toughness, the treatment enables the wear resistance and the toughness of the grinding ball to be perfectly combined, the hardness and the wear resistance of the whole grinding ball are further improved, and the service life of the grinding ball is greatly prolonged.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.