阅读说明：本技术 0Cr13Ni8Mo2Al不锈钢的均匀化处理方法 (Homogenization treatment method of 0Cr13Ni8Mo2Al stainless steel ) 是由 张志宏 白青青 余志川 隆文庆 郑淮北 于 2019-10-22 设计创作，主要内容包括：本发明涉及不锈钢领域,尤其是一种有效地改善0Cr13Ni8Mo2Al不锈钢的微观偏析的0Cr13Ni8Mo2Al不锈钢的均匀化处理方法,包括如下步骤：将采用0Cr13Ni8Mo2Al不锈钢制得的铸锭或者工件随炉加热至1130℃～1170℃,空气气氛,保温时间为36h～48h,热处理结束后随炉冷却或者空冷；当0Cr13Ni8Mo2Al不锈钢经过上述处理后,Al、Cr、Mo和Ni的残余偏析系数δ均小于0.2时,认为均匀化过程完成,即0Cr13Ni8Mo2Al不锈钢完成了均匀化过程。通过铸锭或者工件随炉加热至1130℃～1170℃,空气气氛,保温时间为36h～48h,热处理结束后随炉冷却或者空冷的处理方式后,成分的均匀化带来了造成组织上差别的降低,提高了钢锭的冲击韧性和塑性,降低了热裂倾向性,钢锭的热加工性能更优。本发明尤其适用于0Cr13Ni8Mo2Al不锈钢的均匀化处理工艺之中。(The invention relates to the field of stainless steel, in particular to a homogenization treatment method of 0Cr13Ni8Mo2Al stainless steel for effectively improving the microsegregation of the 0Cr13Ni8Mo2Al stainless steel, which comprises the following steps: heating an ingot or a workpiece made of 0Cr13Ni8Mo2Al stainless steel to 1130-1170 ℃ along with a furnace, keeping the temperature for 36-48 h in an air atmosphere, and cooling along with the furnace or air cooling after the heat treatment is finished; when the residual segregation coefficients δ of Al, Cr, Mo and Ni are all less than 0.2 after the 0Cr13Ni8Mo2Al stainless steel is subjected to the above treatment, the homogenization process is considered to be completed, i.e., the 0Cr13Ni8Mo2Al stainless steel is subjected to the homogenization process. The ingot or the workpiece is heated to 1130-1170 ℃ along with the furnace, the air atmosphere is kept for 36-48 h, and after the heat treatment is finished and the treatment mode of furnace cooling or air cooling is carried out, the reduction of difference on the structure is brought by the homogenization of the components, the impact toughness and the plasticity of the steel ingot are improved, the hot cracking tendency is reduced, and the hot workability of the steel ingot is better. The invention is particularly suitable for the homogenization treatment process of the 0Cr13Ni8Mo2Al stainless steel.)

The homogenization treatment method of 1.0Cr13Ni8Mo2Al stainless steel is characterized by comprising the following steps: heating an ingot or a workpiece made of 0Cr13Ni8Mo2Al stainless steel to 1130-1170 ℃ along with a furnace, keeping the temperature for 36-48 h in an air atmosphere, and cooling along with the furnace or air cooling after the heat treatment is finished; when the residual segregation coefficients δ of Al, Cr, Mo and Ni are all less than 0.2 after the 0Cr13Ni8Mo2Al stainless steel is subjected to the above treatment, the homogenization process is considered to be completed, i.e., the 0Cr13Ni8Mo2Al stainless steel is subjected to the homogenization process.

2. The method of homogenizing 0Cr13Ni8Mo2Al stainless steel according to claim 1, wherein the 0Cr13Ni8Mo2Al stainless steel comprises as major components: less than or equal to 0.5 percent of carbon, less than or equal to 0.10 percent of silicon, less than or equal to 0.10 percent of manganese, less than or equal to 0.010 percent of phosphorus, less than or equal to 0.008 percent of sulfur, 12.25 to 13.25 percent of chromium, 7.50 to 8.50 percent of nickel, 2.00 to 2.50 percent of molybdenum, 0.90 to 1.35 percent of aluminum, less than or equal to 0.010 percent of nitrogen, and the balance being iron.

3. The method for homogenizing 0Cr13Ni8Mo2Al stainless steel according to claim 1 or 2, wherein: the thickness of the oxide layer of the cast ingot or the steel part is 600-1000 μm.

4. The method for homogenizing 0Cr13Ni8Mo2Al stainless steel according to claim 1 or 2, wherein: the grain size of the ingot or the steel part is distributed between 300 and 400 mu m.

Technical Field

The invention relates to the field of stainless steel, in particular to a homogenization treatment method of 0Cr13Ni8Mo2Al stainless steel.

Background

The 0Cr13Ni8Mo2Al steel is a high strength martensitic precipitation hardening stainless steel by double vacuum smelting. The stainless steel has high strength, excellent fracture toughness, good transverse mechanical property and stress corrosion resistance in marine environment, and is widely applied to the fields of space navigation, nuclear reactors, petrochemical industry and the like, such as cold heading and machining fasteners, airplane parts, reactor parts and petrochemical equipment. However, since 0Cr13Ni8Mo2Al stainless steel still has micro segregation after double vacuum smelting, the influence of the micro segregation on the mechanical properties of steel ingots and forgings is obvious, and the impact toughness and plasticity of the steel ingots are reduced due to the difference in structure caused by uneven components, so that the hot cracking tendency is increased, and the steel ingots are difficult to be hot-processed.

Disclosure of Invention

the invention aims to provide a homogenization treatment method of 0Cr13Ni8Mo2Al stainless steel, which can effectively improve the microsegregation of the 0Cr13Ni8Mo2Al stainless steel.

The technical scheme adopted by the invention for solving the technical problems is as follows: the homogenizing treatment method of the 0Cr13Ni8Mo2Al stainless steel is characterized by comprising the following steps: heating an ingot or a workpiece made of 0Cr13Ni8Mo2Al stainless steel to 1130-1170 ℃ along with a furnace, keeping the temperature for 36-48 h in an air atmosphere, and cooling along with the furnace or air cooling after the heat treatment is finished; when the residual segregation coefficients δ of Al, Cr, Mo and Ni are all less than 0.2 after the 0Cr13Ni8Mo2Al stainless steel is subjected to the above treatment, the homogenization process is considered to be completed, i.e., the 0Cr13Ni8Mo2Al stainless steel is subjected to the homogenization process.

Further, the 0Cr13Ni8Mo2Al stainless steel comprises the following main components: less than or equal to 0.5 percent of carbon, less than or equal to 0.10 percent of silicon, less than or equal to 0.10 percent of manganese, less than or equal to 0.010 percent of phosphorus, less than or equal to 0.008 percent of sulfur, 12.25 to 13.25 percent of chromium, 7.50 to 8.50 percent of nickel, 2.00 to 2.50 percent of molybdenum, 0.90 to 1.35 percent of aluminum, less than or equal to 0.010 percent of nitrogen, and the balance being iron.

Furthermore, the thickness of the oxide layer of the ingot or the steel piece is 600-1000 μm.

Furthermore, the grain size of the ingot or the steel piece is distributed between 300 and 400 mu m.

The invention has the beneficial effects that: in actual use, the ingot or the workpiece is heated to 1130-1170 ℃ along with the furnace, the air atmosphere is kept for 36-48 h, and after the heat treatment is finished and the treatment mode of furnace cooling or air cooling is carried out, the reduction of difference on the structure is brought by the homogenization of the components, the impact toughness and plasticity of the steel ingot are improved, the hot cracking tendency is reduced, and the hot workability of the steel ingot is better. The invention is particularly suitable for the homogenization treatment process of the 0Cr13Ni8Mo2Al stainless steel.

Detailed Description

The homogenizing treatment method of the 0Cr13Ni8Mo2Al stainless steel comprises the following steps: heating an ingot or a workpiece made of 0Cr13Ni8Mo2Al stainless steel to 1130-1170 ℃ along with a furnace, keeping the temperature for 36-48 h in an air atmosphere, and cooling along with the furnace or air cooling after the heat treatment is finished; when the residual segregation coefficients δ of Al, Cr, Mo and Ni are all less than 0.2 after the 0Cr13Ni8Mo2Al stainless steel is subjected to the above treatment, the homogenization process is considered to be completed, i.e., the 0Cr13Ni8Mo2Al stainless steel is subjected to the homogenization process.

The ingot or the workpiece is heated to 1130-1170 ℃ along with the furnace, the temperature is kept for 36-48 h under the air atmosphere, and the ingot or the workpiece is cooled along with the furnace or air after the heat treatment is finished, so that good homogenization treatment is realized. Air cooling refers to natural cooling in the atmospheric environment, and the air atmosphere refers to the condition that no protective atmosphere is introduced into the furnace during heating. Wherein, when the residual segregation coefficients δ of Al, Cr, Mo and Ni are all less than 0.2, the homogenization process is considered to be completed, i.e., the 0Cr13Ni8Mo2Al stainless steel completes the homogenization process. The residual segregation index delta in the invention is calculated by adopting the following formula:

In the formula, C_max ^tAnd C_min ^tThe highest concentration and the lowest concentration of the alloy elements after t hours of homogenization treatment, C_max ⁰And C_min ⁰The highest concentration and the lowest concentration of the original state alloy elements. The residual segregation coefficient δ is related to parameters such as diffusion coefficient D of the element, dendrite spacing L, and homogenization time t. Theoretically, when the residual segregation coefficient δ is 0, the element distribution reaches complete uniformity. However, in actual production, generally when δ is < 0.2, the homogenization process is considered complete. When the homogenization time is short, the residual segregation index is more than 0.2, and the composition segregation still exists in the ingot or the workpiece; the delta value changes less as the homogenization treatment time is prolonged, but the growth of the oxide layer thickness and the grain size needs to be controlled for subsequent hot working and reduction of the yield.

In order to further improve the quality of the treatment, it is preferable to adopt: the 0Cr13Ni8Mo2Al stainless steel mainly comprises the following components: less than or equal to 0.5 percent of carbon, less than or equal to 0.10 percent of silicon, less than or equal to 0.10 percent of manganese, less than or equal to 0.010 percent of phosphorus, less than or equal to 0.008 percent of sulfur, 12.25 to 13.25 percent of chromium, 7.50 to 8.50 percent of nickel, 2.00 to 2.50 percent of molybdenum, 0.90 to 1.35 percent of aluminum, less than or equal to 0.010 percent of nitrogen, and the balance being iron. The 0Cr13Ni8Mo2Al stainless steel can better adapt to and meet the requirement of homogenization treatment, thereby optimizing the treatment quality.

As a quality standard at the later stage of the processing, generally: the thickness of the oxide layer of the cast ingot or the steel part is 600-1000 μm. The grain size of the ingot or the steel part is preferably distributed between 300 and 400 mu m.