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CN-121992313-A - Nano composite precipitation strengthening austenitic superhard steel and preparation method thereof

CN121992313ACN 121992313 ACN121992313 ACN 121992313ACN-121992313-A

Abstract

The invention relates to the technical field of austenitic stainless steel, in particular to nano composite precipitation strengthening austenitic superhard steel and a preparation method thereof, wherein the alloy comprises the following components in percentage by weight: 0.75-0.9 wt.% of C, 5.5-8.5 wt.% of Mn, 6.0-10.0 wt.% of Ni, 10.0-13.0 wt.% of Cr, 1.0-2.5 wt.% of Mo, and V:2.0 to 2.5wt.%, cu 2.0 to 4.0 wt.%, si 0.2 to 1.0 wt.%, ti: 0.03-0.100 wt%, 0.05-0.20 wt% of N, 0.2-0.8 wt% of Al, 0.01-0.015 wt% of Ce, and the balance being Fe. The HRC of the steel obtained by the invention can reach 48.8 at most, the tensile strength can reach 1375MPa, the austenitic stainless steel with the grain size of 30-50 mu m is free from AlN, mnS, VC, cr C3 which is leached in a large amount, cr23C6 which is leached in a large amount is not present at the grain boundary, microscopic and macroscopic cracks are not present, and the steel consists of pure FCC austenite.

Inventors

  • SONG CHENGHAO
  • SHEN WEIYI
  • CHEN JUNYU
  • XIE ZONGZHENG
  • WANG HAOLIANG
  • SUN ZHENZHONG

Assignees

  • 东莞理工学院

Dates

Publication Date
20260508
Application Date
20260205

Claims (9)

  1. 1. A nano composite precipitation strengthening austenitic superhard steel is characterized in that the alloy comprises ：C:0.75~0.9wt.%、Mn:5.5~8.5wt.%、Ni:6.0~10.0wt.%、Cr:10.0~13.0wt.%、Mo:1.0~2.5wt.%、V：2.0~2.5wt.%、Cu:2.0~4.0 wt.%、Si:0.2~1.0wt.%、Ti：0.03~0.100wt.%、N:0.05~0.20wt.%、Al:0.2~0.8wt.%、Ce:0.01~0.015 wt.%、 weight percent of Fe and the balance of Fe.
  2. 2. A nano composite precipitation strengthening austenitic superhard steel is characterized in that the yield strength of the superhard steel is more than 1000 MPa, the hardness HRC is more than 40, precipitates of nano VC and Cu with volume fraction more than 10% are dispersed in a matrix, and massive liquid precipitation harmful phases VC and Cr7C3 are not generated.
  3. 3. The method for preparing the nano composite precipitation-strengthened austenitic superhard steel according to any one of claims 1 to 2, wherein the method comprises the following steps: s1, weighing alloy components, and weighing corresponding C, mn, ni, cr, mo, V, cu, si, ti, N, al, ce and Fe according to the weight percentage of the alloy components; s2, carrying out vacuum smelting, casting, electroslag remelting, forging and hot rolling on the alloy components weighed in the step S1 to obtain a hot rolled bar; S3, carrying out solution treatment on the hot rolled bar obtained in the step S2; And S4, aging the bar material treated in the step S3 to obtain superhard steel material.
  4. 4. The method for preparing nano-composite precipitation-strengthened austenitic superhard steel according to claim 3, wherein the forging temperature in the step S2 is controlled to 1180-1230 ℃, and the forging ratio is controlled to 4-6.
  5. 5. The method of producing a nanocomposite precipitation-strengthened austenitic superhard steel according to claim 3, wherein the square billet obtained by forging in step S2 is 150X 150mm.
  6. 6. The method for preparing the nano composite precipitation strengthening austenitic superhard steel according to claim 3, wherein the specific operation of hot rolling in the step S2 is that the heat preservation is carried out for 4-5 hours at 1180-1230 ℃, then the hot rolling is carried out at 1000-1150 ℃, and the total reduction rate is 66-86%.
  7. 7. The method for preparing the nano composite precipitation strengthening austenitic superhard steel according to claim 3, wherein the diameter of the hot rolled bar in the step S2 is 20-50 mm.
  8. 8. The method for preparing the nano composite precipitation strengthening austenitic superhard steel according to claim 3, wherein the specific operation of the solution treatment in the step S3 is that the hot rolled bar is subjected to heat preservation at 1200-1230 ℃ for 3-6 hours and then water quenching to room temperature.
  9. 9. The method for preparing the nano composite precipitation strengthening austenitic superhard steel according to claim 3, wherein the hot rolled bar obtained in the step S4 is subjected to heat preservation at 650-750 ℃ for 4-6 hours, and then is subjected to water quenching to room temperature.

Description

Nano composite precipitation strengthening austenitic superhard steel and preparation method thereof Technical Field The invention relates to the technical field of austenitic stainless steel, in particular to nano composite precipitation strengthening austenitic superhard steel and a preparation method thereof. Background Austenitic stainless steel is an alloy material that is widely used, has excellent oxidation and corrosion resistance, and plays an important role in various fields (e.g., automobiles, ships, energy sources, chemical industry). But its hardness and wear resistance are poor, limiting the application of austenitic stainless steel. The solution treatment can promote carbide in the material to dissolve into a matrix, and lays a foundation for the subsequent strengthening processes such as age hardening, and the like, so that it is important to design the optimal solution treatment condition. According to SEM experimental analysis and statistics, when the temperature is higher than 1180 ℃ and the time is longer than 5 hours, most Cr7C3 can be dissolved into a matrix, and the heat preservation time in the solid solution treatment process in the preparation method of high-strength high-toughness large-expansion austenitic stainless steel in the Chinese patent CN 119800250B is too short, so that the effect of solid solution treatment cannot be well achieved. As can be obtained by EBSD experimental analysis, when the solid solution temperature exceeds 1230 ℃, and the heat preservation time is too long, the grain size can grow rapidly. Through careful research on Chinese patent CN120006173A, a preparation method of light, high heat-resistant and good-fatigue-life steel is discovered, wherein the long solution treatment time can cause thicker oxide scales to be generated on the surface of a bar, so that the material is lost, and the grains are at risk of growing. In addition, cooling should be performed rapidly after solution treatment to ensure uniform structure without additional high temperature precipitation of carbides. Chinese patent CN120006173a, "a preparation method of a steel product with light weight, high heat resistance and good fatigue life," is characterized in that after heat treatment, the steel product is quenched to 700 ℃ and then cooled to room temperature with a furnace, so that the material generates larger internal stress, the dimensional stability and mechanical properties are affected in subsequent processing, the temperature is difficult to control in actual production, other high-temperature carbides are precipitated, and the strengthening effect is affected. Through research, C can improve the hardness of steel, but according to the prior research, high C is easy to cause a lot of inclusions in the steel, is large, is easy to crack and has high manufacturing cost. Based on the defects, a great deal of research is carried out to try to provide a nano composite precipitation strengthening austenitic superhard steel and a preparation method thereof, so as to overcome various defects in the prior art. Disclosure of Invention The invention aims to solve the technical problem of providing nano composite precipitation strengthening austenitic superhard steel and a preparation method thereof, wherein the HRC of the obtained steel can reach 48.8 at most, the tensile strength can reach about 1375MPa, the austenitic stainless steel has a grain size of 30-50 mu m, the steel does not have AlN, mnS, VC, cr C3 which is leached in a large amount, cr23C6 which is leached in a large amount does not exist at a grain boundary, microscopic and macroscopic cracks do not exist, and the steel consists of pure FCC austenite. In order to solve the technical problems, the invention adopts the following technical scheme: The nano composite precipitation strengthening austenitic superhard steel comprises ：C:0.75~0.9wt.%、Mn:5.5~8.5wt.%、Ni:6.0~10.0wt.%、Cr:10.0~13.0wt.%、Mo:1.0~2.5wt.%、V：2.0~2.5wt.%、Cu:2.0~4.0 wt.%、Si:0.2~1.0 wt.%、Ti：0.03~0.100wt.%、N:0.05~0.20wt.%、Al:0.2~0.8wt.%、Ce:0.01~0.015 wt.%、 weight percent of alloy components and the balance of Fe. Preferably, the superhard steel has yield strength of more than 1000 MPa and hardness HRC of more than 40, wherein precipitates of nano VC and Cu with volume fraction of more than 10% are dispersed in a matrix, and massive liquid-out harmful phases VC and Cr7C3 are not generated. The preparation method of the nano composite precipitation-strengthening austenitic superhard steel material according to any one of the above, comprising the following steps: s1, weighing alloy components, and weighing corresponding C, mn, ni, cr, mo, V, cu, si, ti, N, al, ce and Fe according to the weight percentage of the alloy components; s2, carrying out vacuum smelting, casting, electroslag remelting, forging and hot rolling on the alloy components weighed in the step S1 to obtain a hot rolled bar; S3, carrying out solution treatment on the hot rolled bar obtained in the