17-4PH stainless steel and structure and performance regulation and control method thereof

A technology of stainless steel and structure, which is applied in the field of stainless steel, can solve the problems that cannot be achieved at the same time, and achieve the effect of improving intergranular corrosion resistance

Pending Publication Date: 2022-04-15
NANJING INST OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, traditional heat treatment methods cannot meet the above three requirements at the same time.

Method used

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  • 17-4PH stainless steel and structure and performance regulation and control method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] A 17-4PH stainless steel, the chemical composition (wt%) is: C: 0.04, Si: 0.3, Mn: 0.8, S: 0.002, P: 0.01, Cr: 15.6, Ni: 4.5, Mo: 0.2, Cu: 3.5 , Nb: 0.5, N: 100PPM, wherein, the molar ratio of Nb and C is: n Nb / n C = 1.63.

[0030] A microstructure and performance control method for 17-4PH stainless steel. The stainless steel workpiece is heated to 1050°C for 2 hours, water cooled to room temperature, and the cooling rate is 150°C / S; the stainless steel workpiece is reheated to 935°C for 0.5h, and oil-cooled. To room temperature, the cooling rate is 220°C / S; finally carry out aging treatment at 520°C for 4h.

[0031] After testing, the final obtained 17-4PH stainless steel workpiece has a hardness of 38.2HRC and a low temperature impact energy of -46°C of 28J. The intergranular corrosion resistance adopts the double-loop potentiodynamic reactivation method (DL-EPR), Ir / Ia=0.39, which meets the technical requirements of the workpiece.

Embodiment 2

[0033] A 17-4PH stainless steel, the chemical composition (wt%) is: C: 0.04, Si: 0.3, Mn: 0.8, S: 0.002, P: 0.01, Cr: 15.6, Ni: 4.5, Mo: 0.2, Cu: 3.5 , Nb: 0.5, N: 100PPM, wherein, the molar ratio of Nb and C is: n Nb / n C = 1.63.

[0034] A microstructure and performance control method for 17-4PH stainless steel. The stainless steel workpiece is heated to 1050°C for 2 hours, cooled to room temperature with water at a cooling rate of 150°C / S; then the sample is reheated to 935°C for 1 hour, and oil cooled to At room temperature, the cooling rate is 220°C / S; finally, the aging treatment is carried out at 520°C for 4 hours.

[0035] After testing, the hardness of the finally obtained 17-4PH stainless steel workpiece is 37.6HRC; the low temperature impact energy at -46°C is 31J. The intergranular corrosion resistance adopts the double-loop potentiodynamic reactivation method (DL-EPR), Ir / Ia=0.35, which meets the technical requirements of the workpiece.

Embodiment 3

[0037] A 17-4PH stainless steel, the chemical composition (wt%) is: C: 0.04, Si: 0.3, Mn: 0.8, S: 0.002, P: 0.01, Cr: 15.6, Ni: 4.5, Mo: 0.2, Cu: 3.5 , Nb: 0.45, N: 80PPM. Wherein, the molar ratio of Nb and C is: n Nb / n C = 1.47.

[0038] A microstructure and performance control method for 17-4PH stainless steel. The stainless steel workpiece is heated to 1050°C for 2 hours, cooled to room temperature with water at a cooling rate of 300°C / S; then the sample is reheated to 950°C for 0.5h, oil cooled To room temperature, the cooling rate is 100°C / S; finally, aging treatment is carried out at 520°C for 4 hours.

[0039] After testing, the final 17-4PH stainless steel workpiece has a hardness of 38.4HRC and a low-temperature impact energy of -46°C of 30J. The intergranular corrosion resistance adopts the double-loop potentiodynamic reactivation method (DL-EPR), Ir / Ia=0.37, which meets the technical requirements of the workpiece.

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Abstract

The invention discloses 17-4PH stainless steel, which comprises the following components in percentage by mass: 0.035 to 0.05 percent of C, less than or equal to 0.5 percent of Si, 0.6 to 1.0 percent of Mn, less than or equal to 0.005 percent of S, less than or equal to 0.025 percent of P, 14.0 to 17.0 percent of Cr, 4.5 to 6.0 percent of Ni, 0.15 to 0.5 percent of Mo, 3.0 to 4.5 percent of Cu, 0.35 to 0.5 percent of Nb, less than or equal to 120PPM of N and the balance of Fe. Wherein nNb / nC is greater than 1.25. The invention further discloses a structure and performance regulation and control method of the 17-4PH stainless steel. The structure and performance regulation and control method comprises the following steps that S1, a stainless steel workpiece is prepared from the raw materials according to the proportion; and S2, the stainless steel workpiece is heated to 1040-1060 DEG C for solution treatment. The 17-4PH stainless steel with high strength, high low-temperature toughness and better intergranular corrosion resistance can be obtained through the preparation method.

Description

technical field [0001] The invention relates to a 17-4PH stainless steel and a method for regulating its structure and performance, and belongs to the technical field of stainless steel. Background technique [0002] 17-4PH stainless steel was disclosed in the heat treatment technology and equipment journal of issue 03 in 2019, and its abstract records that "17-4PH alloy is a precipitation-hardened martensitic stainless steel composed of copper, niobium / columbium. It is equivalent to the Chinese brand: 0Cr17Ni4Cu4Nb. It has the characteristics of high strength, hardness and corrosion resistance. After heat treatment, the mechanical properties are more perfect, and the compressive strength can reach 1100-1300MPa. It cannot be used at ambient temperatures higher than 300°C or at very low temperatures. For the atmosphere , dilute acid or salt atmosphere have good corrosion resistance." [0003] In summary, 17-4PH is a martensitic precipitation hardening stainless steel. Marten...

Claims

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Application Information

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IPC IPC(8): C22C38/48C22C38/44C22C38/42C22C38/04C22C38/02C21D1/18
Inventor 赵秀明刘凯旋薛松高志刚高欣汪鹏贺显聪吴萌
Owner NANJING INST OF TECH
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