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CN-121380753-B - Special metal material and surface interface heat treatment process thereof

CN121380753BCN 121380753 BCN121380753 BCN 121380753BCN-121380753-B

Abstract

The application belongs to the technical field of heat treatment of special metal materials, and particularly relates to a special metal material and a surface interface heat treatment process thereof, aiming at the problem of unbalance of the surface hardness, the core toughness and the overall corrosion resistance of conventional stainless steel, the material comprises, by weight, 0.03-0.08% of C, 18.0-22.0% of Cr, 8.0-12.0% of Ni, 0.05-0.15% of Nb, 1.5-2.5% of Mo and the balance of Fe, wherein the process comprises the steps of 1050-1150 ℃ solid solution, 850-900 ℃ low-temperature rare earth carburization, 0.3-0.8% of nano La 2 O 3 , induction quenching in a 900-950 ℃ temperature environment and tempering in a 200-250 ℃ temperature environment. The application realizes the comprehensive improvement of the surface hardness, the core impact toughness, the neutral salt spray corrosion resistance and other performances, the workpiece made of the special metal material is suitable for heavy load corrosion working conditions, and the process is modified by the existing equipment, so that the cost is low.

Inventors

  • ZHANG GUIYUN
  • ZHANG ZHIGANG
  • LI WANZHONG
  • DU XIAO
  • YANG KAI
  • SHANG JIANPING
  • LV YANG
  • SUN DAPENG

Assignees

  • 淄博鲁蒙金属科技有限公司

Dates

Publication Date
20260508
Application Date
20251030

Claims (9)

  1. 1. A surface interface heat treatment process for special metal materials is characterized in that, The special metal material comprises the following components in parts by weight: C：0.03-0.08%、Cr：18.0-22.0%、Ni：8.0-12.0%、Nb：0.05-0.15%、Mo：1.5-2.5%、Si：≤0.8%、Mn：≤1.0%、P：≤0.03%、S：≤0.01%, The balance being Fe; the process comprises the following steps: S1, substrate solid solution treatment, namely placing a special metal material workpiece into a furnace, preserving heat for 1.5-3 hours at 1050-1150 ℃, and then cooling to room temperature by water; S2, low-temperature rare earth carburization, namely placing a workpiece subjected to solid solution in a carburizing furnace, preserving heat for 3-5 hours at 850-900 ℃, wherein a carburizing agent is acetone and nitrogen, 0.3-0.8% of nano lanthanum oxide is added into the carburizing agent, slowly cooling to 500 ℃ after heat preservation is finished, and then air cooling to room temperature; S3, carrying out local induction quenching and low-temperature tempering, namely carrying out induction heating on the carburized workpiece, wherein the heating temperature is 900-950 ℃, preserving heat for 8-15min, then cooling the workpiece to room temperature by oil, placing the workpiece in a furnace, tempering for 1-2h at 200-250 ℃, and finally cooling the workpiece to room temperature by air.
  2. 2. The surface interface heat treatment process according to claim 1, wherein in step S2, a flow ratio of acetone to nitrogen is 1 (35-45).
  3. 3. The surface interface heat treatment process according to claim 1, wherein in step S1, the heat-retaining time of the solution treatment is calculated as the thickness of the work piece, specifically 1h/20mm.
  4. 4. The surface interface heat treatment process according to claim 1, wherein in step S3, the heating frequency of the induction hardening is 15 to 25kHz.
  5. 5. The surface-interface heat treatment process according to claim 1, wherein the carbon potential of the low-temperature rare earth carburization in step S2 is controlled to be 0.8-1.2% C to regulate the surface carbon content and carbide precipitation density.
  6. 6. The surface interface heat treatment process according to claim 1, wherein in step S2, the cooling rate of slow cooling to 500 ℃ is 5-10 ℃/min, and internal stress concentration and abnormal precipitation of carbide due to rapid cooling are avoided.
  7. 7. The surface interface heat treatment process according to claim 1, wherein in step S2, the depth of the hardening layer of the local induction hardening is 0.5-2.0mm, and the hardness gradient of the hardening layer and the core is less than or equal to 5HRC/mm, so as to ensure smooth transition of mechanical properties.
  8. 8. The surface interface heat treatment process according to claim 1, wherein the mass percentage of Nb is 0.08-0.12%.
  9. 9. The surface interface heat treatment process according to claim 1, wherein the mass percentage of Cr is 19.0-21.0%, and the mass percentage of Mo is 1.8-2.2%.

Description

Special metal material and surface interface heat treatment process thereof Technical Field The invention belongs to the technical field of heat treatment of special metal materials, and particularly relates to a special metal material and a surface interface heat treatment process thereof. Background Stainless steel has excellent corrosion resistance and is widely applied to the fields of mechanical manufacture, chemical equipment, rail transit and the like. However, the conventional stainless steel has lower surface hardness, is easy to generate abrasion failure under the heavy-load and high-frequency friction working condition, and is difficult to meet the use requirement of the transmission part on the surface hardness. In order to improve the surface hardness of stainless steel, two types of strengthening schemes are mainly adopted in the prior art. One is the traditional surface carburization process, which generally adopts high-temperature carburization at 950-1050 ℃, although the surface carbon content can be improved, cr element and carbon in stainless steel are easy to combine to form continuous netlike and massive carbide. The carbide can damage the passivation film on the surface of the stainless steel, so that the corrosion resistance is greatly reduced, the deformation of a workpiece after carburization is large, and the hardness and the corrosion resistance cannot be simultaneously considered; the method is characterized in that the whole hardness of the material can be improved by the whole quenching and tempering process after the whole quenching is heated to an austenite region, but the toughness of the core is obviously reduced, the difference between the core and the surface hardness is small, the working condition requirements of surface wear resistance and core impact resistance cannot be met, meanwhile, the traditional quenching is easy to form coarse martensite characteristics of coarse massive martensite, and the toughness degradation is further aggravated. Therefore, development of a special stainless steel metal material and a matched heat treatment process which simultaneously meet the synergistic optimization of surface hardness, core toughness and overall corrosion resistance is needed. Disclosure of Invention In order to solve the problems in the prior art, the invention aims to provide a special metal material and a surface interface heat treatment process thereof. The technical scheme of the invention is that the special metal material comprises the following components in parts by weight: C：0.03-0.08%、Cr：18.0-22.0%、Ni：8.0-12.0%、Nb：0.05-0.15%、Mo：1.5-2.5%、Si：≤0.8%、Mn：≤1.0%、P：≤0.03%、S：≤0.01%, The balance being Fe. Preferably, the mass percentage of Nb is 0.08-0.12%. Preferably, the mass percentage of Cr is 19.0-21.0%, and the mass percentage of Mo is 1.8-2.2%. In order to better the technical scheme, the invention also provides a surface interface heat treatment process of the special metal material, which comprises the following steps: S1, substrate solid solution treatment, namely placing a special metal material workpiece into a furnace, preserving heat for 1.5-3 hours at 1050-1150 ℃, and then cooling to room temperature by water; S2, low-temperature rare earth carburization, namely placing a workpiece subjected to solid solution in a carburizing furnace, preserving heat for 3-5 hours at 850-900 ℃, wherein a carburizing agent is acetone and nitrogen, 0.3-0.8% of nano lanthanum oxide is added into the carburizing agent, slowly cooling to 500 ℃ after heat preservation is finished, and then air cooling to room temperature; S3, carrying out local induction quenching and low-temperature tempering, namely carrying out induction heating on the carburized workpiece, wherein the heating temperature is 900-950 ℃, preserving heat for 8-15min, then cooling the workpiece to room temperature by oil, placing the workpiece in a furnace, tempering for 1-2h at 200-250 ℃, and finally cooling the workpiece to room temperature by air. Preferably, in step S2, the flow ratio of acetone to nitrogen is 1 (35-45). Preferably, in step S1, the heat-retaining time of the solution treatment is calculated in terms of the thickness of the workpiece, specifically 1h/20mm. Preferably, in step S3, the heating frequency of the induction hardening is 15-25kHz. Preferably, in the step S2, the carbon potential of the low-temperature rare earth carburization is controlled to be 0.8-1.2% C so as to regulate the surface carbon content and the carbide precipitation density. Preferably, in step S2, the cooling rate of slow cooling to 500 ℃ is 5-10 ℃ per minute, so that internal stress concentration and abnormal precipitation of carbide caused by rapid cooling are avoided. Preferably, in the step S2, the depth of a hardening layer of the local induction hardening is 0.5-2.0mm, and the hardness gradient of the hardening layer and the core part is less than or equal to 5HRC/mm, so as to ensure stable mechanical property