阅读说明：本技术 激光熔覆修复连铸结晶器足辊用金属粉末及其制备方法 (Metal powder for repairing continuous casting crystallizer foot roller through laser cladding and preparation method thereof ) 是由 吴涛 潘洁 单立东 孔祥丽 周华 陆亚轩 谷凤龙 鄂涛 藏正超 安贺顺 黄智杰 于 2021-08-09 设计创作，主要内容包括：本发明提供了一种激光熔覆修复连铸结晶器足辊用金属粉末及其制备方法,所提供的的金属粉末的化学成分组成及其质量百分含量为：C 0.02%～0.05%、Si 0.90%～1.20%、Mn 0.20%～0.30%、B 0.60%-0.90%、Cr 13.0%～15.0%、Ni 4.0%～6.0%、Mo 2.0%～3.0%,余量为Fe和不可避免的杂质；制备过程包括感应熔炼、雾化制粉、粉末筛分和真空脱气封装工序。通过合理的成分设计及工艺控制,制备的金属粉末熔覆后具有良好抗磨损和抗腐蚀综合性能,熔覆层获得35-45HRC的硬度。(The invention provides metal powder for repairing a foot roller of a continuous casting crystallizer by laser cladding and a preparation method thereof, wherein the metal powder comprises the following chemical components in percentage by mass: 0.02 to 0.05 percent of C, 0.90 to 1.20 percent of Si, 0.20 to 0.30 percent of Mn, 0.60 to 0.90 percent of B, 13.0 to 15.0 percent of Cr, 4.0 to 6.0 percent of Ni, 2.0 to 3.0 percent of Mo, and the balance of Fe and inevitable impurities; the preparation process comprises the working procedures of induction melting, atomization powder preparation, powder screening and vacuum degassing packaging. Through reasonable component design and process control, the prepared metal powder has good comprehensive wear-resistant and corrosion-resistant properties after cladding, and the cladding layer has the hardness of 35-45 HRC.)

1. The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding is characterized by comprising the following chemical components in percentage by mass: 0.02 to 0.05 percent of C, 0.90 to 1.20 percent of Si, 0.20 to 0.30 percent of Mn, 0.60 to 0.90 percent of B, 13.0 to 15.0 percent of Cr, 4.0 to 6.0 percent of Ni, 2.0 to 3.0 percent of Mo, and the balance of Fe and inevitable impurities.

2. The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding according to claim 2, wherein the sphericity of the metal powder is not less than 90%, and the particle size is normally distributed between 50-150 um.

3. A preparation method of metal powder for repairing a foot roller of a continuous casting crystallizer by laser cladding is characterized by comprising the working procedures of induction melting, atomization powder preparation, powder screening and vacuum degassing packaging.

4. The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding according to claim 3, wherein the specific operation of the induction melting is as follows: carrying out induction heating smelting on the raw material components of the metal powder in the claim 1 by utilizing induction heating, wherein the heating temperature is 1600-1700 ℃, and after the raw material is completely melted, carrying out heat preservation homogenization for 5-10 minutes to obtain a liquid alloy melt.

5. The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding according to claim 3 or 4, wherein the atomization powder preparation comprises the following specific operations: and pouring the liquid alloy melt obtained by induction melting into a middle drain ladle, freely flowing into a gas atomization furnace downwards through a flow guide pipe at the bottom of the middle drain ladle, crushing the liquid alloy melt into fine liquid drops under the impact action of high-speed inert gas flow, cooling and solidifying to obtain martensite stainless steel powder, and carrying the martensite stainless steel powder into a powder collecting device by gas.

6. The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding according to claim 5, wherein the temperature of the middle breakout ladle is controlled to be 1100-1200 ℃.

7. The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding as claimed in claim 5, wherein the atomizing gas in the gas atomizing furnace is high-purity nitrogen, and the gas pressure is 3-5 MPa.

8. The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding according to claim 5, wherein the particle size of the powder obtained by powder screening is 50-150 um.

9. The method for preparing the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding according to claim 3, wherein the vacuum degree of the vacuum degassing and packaging process is 10-2 Pa.

Technical Field

The invention relates to the field of metal powder and preparation thereof, in particular to metal powder for repairing a foot roller of a continuous casting crystallizer by laser cladding and a preparation method thereof.

Background

Laser cladding is a surface strengthening method which is used for rapidly heating and melting alloy powder or metal ceramic powder and the surface of a matrix under the action of laser and forming metallurgical bonding with the matrix material, thereby obviously improving the characteristics of wear resistance, corrosion resistance, heat resistance, oxidation resistance and the like of the surface of the matrix. The method can prepare a high-performance alloy surface on a cheap metal substrate, repair the failure part of the part, obviously reduce the cost and save precious and rare metal materials. The cladding layer and the base material have high strength and good extrusion resistance and wear resistance, and become one of important means for preparing new materials, quickly forming metal parts and green remanufacturing of failed metal parts.

The continuous casting crystallizer foot roll is arranged below the crystallizer to guide the entry of a head of a ingot, and provides support for a casting blank after a solidified blank shell exits the crystallizer so as to reduce the occurrence of bulging and steel leakage of the casting blank and also reduce the abrasion of the casting blank on the lower opening of a copper plate of the crystallizer. The continuous casting foot roller has the problems of severe working condition environment, high temperature and friction in contact with a high-temperature casting blank, hot water gas cooling corrosion and the like, which cause foot roller abrasion, corrosion cracking, fatigue damage and the like, the long-term existence of the problem of short service life of the foot roller, the foot roller is frequently taken off line in advance due to foot roller failure, the on-line service cycle is shortened, the spare part consumption is high, and the maintenance workload is large. The repair process adopted at present is surfacing, but the problems that surfacing materials are limited, the surfacing process is easy to cause large deformation stress of the foot roller and the like are faced.

With the increasing maturity of laser cladding technology, the laser cladding technology is continuously developed and applied in the field of ferrous metallurgy. At present, the laser cladding technology is mature in the field of ferrous metallurgy and is applied to hot-rolled wire layer cold rolls, flat head sleeves, rolling mill housings and the like. New application scenes are continuously developed, new powder materials are developed, the traditional processes such as surfacing and the like are replaced by a laser cladding process, the wear resistance, corrosion resistance, high temperature resistance and the like of a workpiece are improved, the service life is prolonged, and great economic benefits are created for a production line.

At present, the main preparation method of metal powder is gas atomization, and the basic principle of the method is a process of breaking liquid metal flow into small liquid drops by using high-speed gas flow and rapidly solidifying the small liquid metal drops into powder. The powder prepared by the gas atomization method has the advantages of high purity, low oxygen content, controllable powder granularity, low production cost, high sphericity and the like, can meet the requirements of laser cladding technology on the performance of metal powder, and becomes the main development direction of high-performance and special alloy powder preparation technology. The method has the problems that less powder materials are matched with new application scenes under different working conditions, and the main problems of low yield of powder preparation powder, high content of oxygen and other impurities and the like exist.

Disclosure of Invention

Aiming at the problems and the defects, the invention provides metal powder for repairing a foot roller of a continuous casting crystallizer by laser cladding and a preparation method thereof. The metal powder prepared by the method has good comprehensive mechanical properties after laser cladding processing, the Rockwell hardness of 35-45HRC, and good impact resistance and corrosion resistance.

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

the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.02 to 0.05 percent of C, 0.90 to 1.20 percent of Si, 0.20 to 0.30 percent of Mn, 0.60 to 0.90 percent of B, 13.0 to 15.0 percent of Cr, 4.0 to 6.0 percent of Ni, 2.0 to 3.0 percent of Mo, and the balance of Fe and inevitable impurities.

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding has the sphericity of more than or equal to 90 percent and the particle size of 50-150 mu m which is in normal distribution.

A preparation method of metal powder for repairing a foot roller of a continuous casting crystallizer by laser cladding comprises the working procedures of induction melting, atomization powder preparation, powder screening and vacuum degassing packaging.

The specific operation of the induction melting of the invention is as follows: the raw material components of the metal powder are subjected to induction heating smelting by utilizing induction heating, the heating temperature is 1600-1700 ℃, and after the raw material is completely melted, the heat preservation is carried out for homogenization for 5-10 minutes to obtain the liquid alloy melt.

The specific operation of the atomized powder preparation of the invention is as follows: and pouring the liquid alloy melt obtained by induction melting into a middle drain ladle, freely flowing into a gas atomization furnace downwards through a flow guide pipe at the bottom of the middle drain ladle, crushing the liquid alloy melt into fine liquid drops under the impact action of high-speed inert gas flow, cooling and solidifying to obtain martensite stainless steel powder, and carrying the martensite stainless steel powder into a powder collecting device by gas.

The temperature of the middle drain ladle is controlled to be 1100-1200 ℃.

The atomizing gas in the gas atomizing furnace is high-purity nitrogen, and the gas pressure is 3-5 MPa.

The specific operation of the powder screening of the invention is as follows: and (3) proportioning the powder with different particle sizes by using an ultrasonic vibration and air flow classification method.

The particle size of the powder obtained by screening and grading is 50-150 um.

The vacuum degree of the vacuum degassing and packaging process is 10-2 Pa.

The invention principle of the invention is as follows: the invention has reasonable chemical component design, adopts ultra-low C design and reduces the cladding residual internal stress; a certain amount of Cr element is added to improve the corrosion resistance, especially the local pitting corrosion performance, and a proper amount of Mo element is added to improve the high-temperature strength of the steel and improve the endurance, creep property and the like of the material; the plasticity and toughness of the material are improved by adding a proper amount of Ni element, and good processability is obtained. Smelting and atomizing to obtain powder; the finished piece processed by laser cladding has good comprehensive mechanical property, the Rockwell hardness is 35-45HRC, and the product has good impact resistance and corrosion resistance.

The invention has the beneficial effects that:

1. the martensitic stainless steel powder prepared by the method has low impurity content, uniform particle size distribution, high powder sphericity, high powder fluidity (less than or equal to 12s/50 g) and high apparent density (more than or equal to 3.8 g/cm)³）。

2. The formed part obtained by laser cladding has uniform and compact structure, good wear resistance and corrosion resistance and excellent mechanical property, and can be applied to part repair under complex working conditions such as a continuous casting crystallizer foot roll and the like.

3. Aiming at the requirement of the laser cladding technology on the particle size of the powder, the martensitic stainless steel powder suitable for the laser cladding technology is prepared by screening and other methods, and is subjected to vacuum degassing packaging treatment, so that the fluidity of the martensitic stainless steel powder is effectively improved.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example 1

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.02% of C, 0.95% of Si, 0.23% of Mn, 0.70% of B, 14.5% of Cr, 6.0% of Ni, 2.6% of Mo, and the balance of Fe and inevitable impurities.

The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following steps:

(1) a smelting process: performing induction heating smelting on 0.02 percent of C, 0.95 percent of Si, 0.23 percent of Mn, 0.70 percent of B, 14.5 percent of Cr, 6.0 percent of Ni, 2.6 percent of Mo and the balance of Fe and inevitable impurities by utilizing induction heating, heating to the temperature of 1700 ℃, and preserving heat for 5 minutes after the raw materials are completely melted to obtain a liquid alloy melt;

(2) atomizing to prepare powder: pouring the liquid alloy melt prepared in the step (1) into a middle drain ladle, wherein the temperature of the middle drain ladle is 1200 ℃, the liquid alloy melt freely flows downwards into a gas atomization furnace through a flow guide pipe at the bottom of the middle drain ladle, the atomization gas in the gas atomization furnace is high-purity nitrogen, the atomization pressure is 4Mpa, the liquid alloy melt is crushed into fine droplets under the impact action of the high-purity nitrogen flow, the fine droplets are cooled and solidified to obtain martensitic stainless steel powder, and the powder falls to the bottom of an atomization cooling tower and is carried into a powder collecting device by the gas;

(3) powder screening: screening and grading the martensitic stainless steel powder prepared in the step (2) to obtain powder with the particle size of 50-150 um;

(4) vacuum degassing: and (4) vacuum degassing the martensitic stainless steel powder obtained by grading in the step (3) under the vacuum degree of 10pa, and packaging.

The martensitic stainless steel powder prepared in the example has an average particle size of 80um, a sphericity of 0.92, a fluidity of 12.8s/50g and a bulk density of 3.91g/cm³(ii) a The powder has good fluidity, smooth surface, no crack, uniform tissue and Rockwell hardness of 36HRC in the laser cladding process, and the salt spray test shows that the corrosion resistance is good.

Example 2

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.04% of C, 1.10% of Si, 0.30% of Mn, 0.90% of B, 13.0% of Cr, 4.2% of Ni, 3.0% of Mo, and the balance of Fe and inevitable impurities.

The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following steps:

(1) a smelting step of performing induction heating smelting on 0.04% of C, 1.10% of Si, 0.30% of Mn, 0.90% of B, 13.0% of Cr, 4.2% of Ni, 3.0% of Mo and the balance of Fe and inevitable impurities by using induction heating, wherein the heating temperature is 1650 ℃, and the temperature is kept for 6 minutes after the raw materials are completely melted;

(2) atomizing to prepare powder: pouring the liquid alloy melt prepared in the step (1) into a middle drain ladle, wherein the temperature of the middle drain ladle is 1150 ℃, the liquid alloy melt freely flows downwards into a gas atomization furnace through a flow guide pipe at the bottom of the middle drain ladle, the atomization gas in the gas atomization furnace is high-purity nitrogen, the atomization pressure is 5Mpa, the liquid alloy melt is crushed into fine droplets under the impact action of the high-purity nitrogen flow, the fine droplets are cooled and solidified to obtain martensitic stainless steel powder, and the powder falls to the bottom of an atomization cooling tower and is carried into a powder collecting device by the gas;

(3) powder screening: screening and grading the martensitic stainless steel powder prepared in the step (2) to obtain powder with the particle size of 50-150 um;

(4) vacuum degassing: and (4) vacuum degassing the martensitic stainless steel powder obtained by grading in the step (3) at a vacuum degree of 5pa, and packaging.

The martensitic stainless steel powder prepared in the example has the average grain diameter of 86um, the sphericity of 0.91, the fluidity of 12.2s/50g and the apparent density of 3.96g/cm³(ii) a The powder has good fluidity, smooth surface, no crack, uniform tissue and Rockwell hardness of 42HRC in the laser cladding process, and the salt spray test shows that the corrosion resistance is good.

Example 3

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.05% of C, 1.20% of Si, 0.30% of Mn, 0.62% of B, 15.0% of Cr, 6.0% of Ni, 2.0% of Mo, and the balance of Fe and inevitable impurities.

The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following steps:

(1) a smelting process: performing induction heating smelting on 0.05 percent of C, 1.20 percent of Si, 0.30 percent of Mn, 0.62 percent of B, 15.0 percent of Cr, 6.0 percent of Ni, 2.0 percent of Mo and the balance of Fe and inevitable impurities by utilizing induction heating, wherein the heating temperature is 1600 ℃, and after the raw materials are completely melted, preserving heat for 10 minutes to obtain a liquid alloy melt;

(2) atomizing to prepare powder: pouring the liquid alloy melt prepared in the step (1) into a middle drain ladle, wherein the temperature of the middle drain ladle is 1120 ℃, the liquid alloy melt freely flows downwards into a gas atomization furnace through a flow guide pipe at the bottom of the middle drain ladle, the atomization gas in the gas atomization furnace is high-purity nitrogen, the atomization pressure is 3Mpa, the liquid alloy melt is crushed into fine droplets under the impact action of the high-purity nitrogen flow, the fine droplets are cooled and solidified to obtain martensitic stainless steel powder, and the powder falls to the bottom of an atomization cooling tower and is carried into a powder collecting device by the gas;

(3) powder screening: screening and grading the martensitic stainless steel powder prepared in the step (2) to obtain powder with the particle size of 50-150 um;

(4) vacuum degassing: and (4) vacuum degassing the martensitic stainless steel powder obtained by grading in the step (3) under the vacuum degree of 2pa, and packaging.

The martensitic stainless steel powder prepared in this example had an average particle diameter of 90um, a sphericity of 0.93, a fluidity of 12.0s/50g and a bulk density of 3.93g/cm³(ii) a The powder has good fluidity, smooth surface, no crack, uniform tissue and Rockwell hardness of 45HRC in the laser cladding process, and the salt spray test shows that the powder has good corrosion resistance.

Example 4

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.03% of C, 1.0% of Si, 0.25% of Mn, 0.60% of B, 13.5% of Cr, 5.5% of Ni, 2.7% of Mo, and the balance of Fe and inevitable impurities.

The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following steps:

(1) a smelting process: performing induction heating smelting on the following alloy components of 0.03 percent of C, 1.0 percent of Si, 0.25 percent of Mn, 0.60 percent of B, 13.5 percent of Cr, 5.5 percent of Ni, 2.7 percent of Mo and the balance of Fe and inevitable impurities by utilizing induction heating, wherein the heating temperature is 1620 ℃, and after the raw materials are completely melted, keeping the temperature for 8 minutes to obtain a liquid alloy melt;

(2) atomizing to prepare powder: pouring the liquid alloy melt prepared in the step (1) into a middle drain ladle, wherein the temperature of the middle drain ladle is 1160 ℃, the liquid alloy melt freely flows downwards into a gas atomization furnace through a flow guide pipe at the bottom of the middle drain ladle, the atomization gas in the gas atomization furnace is high-purity nitrogen, the atomization pressure is 3Mpa, the liquid alloy melt is crushed into fine droplets under the impact action of the high-purity nitrogen flow, the fine droplets are cooled and solidified to obtain martensitic stainless steel powder, and the powder falls to the bottom of an atomization cooling tower and is carried into a powder collecting device by the gas;

(3) powder screening: screening and grading the martensitic stainless steel powder prepared in the step (2) to obtain powder with the particle size of 50-150 um;

(4) vacuum degassing: and (4) vacuum degassing the martensitic stainless steel powder obtained by grading in the step (3) under the vacuum degree of 4pa, and packaging.

The martensitic stainless steel powder prepared in the example has an average particle size of 88um, a sphericity of 0.95, a fluidity of 11.8s/50g and a bulk density of 3.94g/cm³(ii) a The powder has good fluidity, smooth surface, no crack, uniform tissue and Rockwell hardness of 39HRC in the laser cladding process, and the salt spray test shows that the powder has good corrosion resistance.

Example 5

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.04% of C, 0.9% of Si, 0.20% of Mn, 0.78% of B, 14.8% of Cr, 4.6% of Ni, 2.3% of Mo, and the balance of Fe and inevitable impurities.

The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following steps:

(1) a smelting process: performing induction heating smelting on 0.04% of C, 0.9% of Si, 0.20% of Mn, 0.78% of B, 14.8% of Cr, 4.6% of Ni, 2.3% of Mo and the balance of Fe and inevitable impurities by using induction heating, wherein the heating temperature is 1660 ℃, and after the raw materials are completely melted, preserving heat for 7 minutes to obtain a liquid alloy melt;

(2) atomizing to prepare powder: pouring the liquid alloy melt prepared in the step (1) into a middle drain ladle, wherein the temperature of the middle drain ladle is 1180 ℃, the liquid alloy melt freely flows downwards into a gas atomization furnace through a flow guide pipe at the bottom of the middle drain ladle, the atomization gas in the gas atomization furnace is high-purity nitrogen, the atomization pressure is 4Mpa, the liquid alloy melt is crushed into fine droplets under the impact action of the high-purity nitrogen flow, the fine droplets are cooled and solidified to obtain martensitic stainless steel powder, and the powder falls to the bottom of an atomization cooling tower and is carried into a powder collecting device by the gas;

(3) powder screening: screening and grading the martensitic stainless steel powder prepared in the step (2) to obtain powder with the particle size of 50-150 um;

(4) vacuum degassing: and (4) vacuum degassing the martensitic stainless steel powder obtained by grading in the step (3) at the vacuum degree of 6pa, and packaging.

The martensitic stainless steel powder prepared in this example had an average particle diameter of 84um, a sphericity of 0.93, a fluidity of 13s/50g, and a bulk density of 3.93g/cm³(ii) a The powder has good fluidity, smooth surface, no crack, uniform tissue and Rockwell hardness of 43HRC in the laser cladding process, and the salt spray test shows that the powder has good corrosion resistance.

Example 6

The metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following chemical components in percentage by mass: 0.02% of C, 1.1% of Si, 0.22% of Mn, 0.84% of B, 14.0% of Cr, 4.0% of Ni, 2.8% of Mo, and the balance of Fe and inevitable impurities.

The preparation method of the metal powder for repairing the foot roller of the continuous casting crystallizer by laser cladding comprises the following steps:

(1) a smelting process: performing induction heating smelting on 0.02 percent of C, 1.1 percent of Si, 0.22 percent of Mn, 0.84 percent of B, 14.0 percent of Cr, 4.0 percent of Ni, 2.8 percent of Mo and the balance of Fe and inevitable impurities by utilizing induction heating, wherein the heating temperature is 1680 ℃, and after the raw materials are completely melted, preserving heat for 9 minutes to obtain a liquid alloy melt;

(2) atomizing to prepare powder: pouring the liquid alloy melt prepared in the step (1) into a middle drain ladle, wherein the temperature of the middle drain ladle is 1140 ℃, the liquid alloy melt freely flows downwards into a gas atomization furnace through a flow guide pipe at the bottom of the middle drain ladle, the atomization gas in the gas atomization furnace is high-purity nitrogen, the atomization pressure is 5Mpa, the liquid alloy melt is crushed into fine droplets under the impact action of the high-purity nitrogen flow, the fine droplets are cooled and solidified to obtain martensitic stainless steel powder, and the powder falls to the bottom of an atomization cooling tower and is carried into a powder collecting device by the gas;

(3) powder screening: screening and grading the martensitic stainless steel powder prepared in the step (2) to obtain powder with the particle size of 50-150 um;

(4) vacuum degassing: and (4) vacuum degassing the martensitic stainless steel powder obtained by grading in the step (3) under the vacuum degree of 8pa, and packaging.

The martensitic stainless steel powder prepared in the example has an average particle size of 92um, a sphericity of 0.95, a fluidity of 11s/50g and a bulk density of 3.95g/cm³(ii) a The powder has good fluidity, smooth surface, no crack, uniform tissue and 35HRC Rockwell hardness in the laser cladding process, and the salt spray test shows that the powder has good corrosion resistance.