A high-strength and toughness Z12CN13 martensitic stainless steel and a manufacturing method thereof

Abstract

The invention discloses a high-strength and toughness Z12CN13 martensitic stainless steel and a manufacturing method thereof. The martensitic stainless steel comprises the following components: C0.11%-0.14%, Si0.3-0.5%, Mn0.6-0.8%, S≤0.005%, P≤0.015%, Cr12.5%-13.0%, Ni1.6%-1.8%, Mo0.4%-0.5%, Cu≤0.1%, N0.02%-0.03%, Co≤0.06%, Nb0.008%-0.012%, V0.05%-0.10%, Ti0.008%-0.012%, and the remainder is Fe and impurities. The manufacturing method thereof, during heat treatment, the quenching temperature is 900-1010°C, and the tempering temperature is 600-700°C. The present invention can significantly expand the manufacturing process parameter window, improve product performance margin, reduce manufacturing difficulty, and increase the yield rate.

Description

Technical Field

[0001] The invention relates to the technical field of improving the performance of martensitic stainless steel, in particular to high-strength and toughness Z12CN13 martensitic stainless steel and a manufacturing method thereof. Background Art

[0002] Z12CN13 (similar grade 1Cr13Ni) is a martensitic stainless steel. After heat treatment and tempering, the stainless steel has high strength, toughness and good shock absorption. It is suitable for manufacturing parts working under corrosive media and impact load conditions, such as a certain component of a pressurized water reactor nuclear power plant.

[0003] Some key components made of this material have high strength-toughness ratio requirements (see Table 1 for details). In order to achieve high strength-toughness requirements, when using conventional Z12CN13 components for manufacturing, the heat treatment process parameter window is narrow, and it is necessary to strictly follow the 950-990°C quenching temperature and 640-670°C tempering temperature control requirements to barely meet the requirements. The actual manufacturing process control requirements are high, the manufacturing difficulty is high, and the forging performance is often reworked or even scrapped due to poor matching of room temperature strength and impact, and the yield rate is relatively low. Therefore, when using conventional Z12CN13 stainless steel materials to manufacture components with high strength-toughness ratio requirements, the process window is narrow, the control requirements during the manufacturing process are high, the manufacturing difficulty is high, and the yield rate is low.

[0004] Table 1 Mechanical examination requirements

[0005] Summary of the invention

[0006] The purpose of the present invention is to provide a high-strength and toughness Z12CN13 martensitic stainless steel and a manufacturing method thereof. The high-strength and toughness Z12CN13 martensitic stainless steel in the present invention can significantly expand the process parameter window during manufacturing, improve product performance margin, reduce manufacturing difficulty, and have a high yield rate.

[0007] The technical solution of the present invention is a high-strength and toughness Z12CN13 martensitic stainless steel, comprising the following components in weight percentage: C 0.11%-0.14%, Si 0.30-0.50%, Mn 0.60-0.80%, S≤0.005%, P≤0.015%, Cr12.50%-13.00%, Ni 1.60%-1.80%, Mo 0.40%-0.50%, Cu≤0.10%, N 0.020%-0.030%, Co≤0.06%, Nb 0.008%-0.012%, V 0.05%-0.10%, Ti 0.008%-0.012%, and the balance is Fe and inevitable impurities.

[0008] The manufacturing method of the high-strength and toughness Z12CN13 martensitic stainless steel mentioned above, when the high-strength and toughness Z12CN13 martensitic stainless steel is heat treated, the quenching temperature is 900-1010°C, and the tempering temperature is 600-700°C.

[0009] In the manufacturing method of the high-strength and toughness Z12CN13 martensitic stainless steel mentioned above, during the heat treatment of the high-strength and toughness Z12CN13 martensitic stainless steel, quenching: heating and keeping warm at 900-1010°C, the holding time is 1h / 50mm, and after the holding period, it is taken out of the furnace and oil-cooled; tempering: heating and keeping warm at 600-700°C, the holding time is 1-3h / mm, and after the holding period, it is taken out of the furnace and air-cooled.

[0010] Compared with the prior art, the high-strength and toughness Z12CN13 martensitic stainless steel of the present invention has the following beneficial effects:

[0011] 1. The strength and toughness of stainless steel meet the following requirements: yield strength Rp0.2 ≥ 620MPa, tensile strength Rm 760 ~ 900MPa, elongation A5 ≥ 14%, shrinkage ≥ 50%, 20℃ impact KV2 ≥ 48J.

[0012] 2. By adding appropriate amounts of Nb, V, and Ti and adjusting the content of other elements, the combined effect of various components can significantly improve the comprehensive mechanical properties of high-strength and toughness Z12CN13 martensitic stainless steel forgings, and enhance the strength and impact resistance margin of martensitic stainless steel. The process parameter window can be extended to 900-1010℃ quenching and 600-700℃ tempering, and both high quenching + high tempering and low quenching + low tempering can meet the performance requirements of forgings, significantly expanding the process parameter window, making it easy to control the process parameters during the manufacturing process, reducing the manufacturing difficulty, reducing rework and scrapping, and improving the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a quenching and tempering heat treatment process for the high-strength and toughness Z12CN13 martensitic stainless steel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0015] Example 1

[0016] A high-strength and toughness Z12CN13 martensitic stainless steel comprises the following components in weight percentage: C 0.11%-0.14%, Si 0.30%-0.50%, Mn 0.60%-0.80%, S≤0.005%, P≤0.015%, Cr12.50%-13.00%, Ni 1.60%-1.80%, Mo 0.40%-0.50%, Cu≤0.10%, N0.020%-0.030%, Co≤0.06%, Nb 0.008%-0.012%, V 0.05%-0.10%, Ti0.008%-0.012%, and the balance is Fe and inevitable impurities.

[0017] The high-strength and toughness Z12CN13 martensitic stainless steel ingot is made by electroslag remelting. The above composition and its percentage are obtained by sampling and testing at different positions of the forging. There are many sampling sites and a large amount of data, so it is summarized by range values. Take the forging made of the high-strength and toughness Z12CN13 martensitic stainless steel ingot described in Example 1, and the measured composition (excluding iron and impurities) is shown in Example 1 in Table 2.

[0018] Comparative Example 1

[0019] A Z12CN13 martensitic stainless steel, the measured composition of its forgings (excluding iron and impurities) is shown in Comparative Example 1 in Table 2.

[0020] Table 2Z12CN13 martensitic stainless steel

[0021]

[0022] Example 2

[0023] Method for manufacturing high-strength and toughness Z12CN13 martensitic stainless steel. The high-strength and toughness martensitic stainless steel with the composition of Example 1 in Table 2 is prepared by Figure 1 The heat treatment process shown is to perform tempering heat treatment at 1010°C quenching + 700°C tempering, 900°C quenching + 600°C tempering, and 960°C quenching + 650°C tempering.

[0024] The Z12CN13 martensitic stainless steel of Comparative Example 1 was also Figure 1 The heat treatment process shown is to perform tempering heat treatment at 1010°C quenching + 700°C tempering, 900°C quenching + 600°C tempering, and 960°C quenching + 650°C tempering.

[0025] Experimental Example 3

[0026] The performance of the Z12CN13 martensitic stainless steel of Example 1 and Comparative Example 1 in Table 2, which were subjected to three groups of quenching and tempering heat treatments at different temperatures, was tested, wherein the tensile test was performed according to GB / T 228-2021, and the impact test was performed according to CB / T 229-2020. The test results are shown in Table 3.

[0027] Table 3 Comparison of mechanical properties of Z12CN13 martensitic stainless steel

[0028]

[0029] According to the mechanical property test results, the process parameter window of the tempering heat treatment of the forgings manufactured by the present invention can be expanded to: 900-1010℃ quenching + 600-700℃ tempering, the manufacturing difficulty is significantly reduced, and the strength and impact toughness of the forgings manufactured by the present invention are significantly better than those manufactured by conventional manufacturing methods, which can significantly improve the yield rate.

[0030] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A high-strength and toughness Z12CN13 martensitic stainless steel, characterized by: The invention comprises the following components in weight percentage: C 0.11%-0.14%, Si 0.30-0.50%, Mn 0.60-0.80%, S≤0.005%, P≤0.015%, Cr12.50%-13.00%, Ni 1.60%-1.80%, Mo 0.40%-0.50%, Cu≤0.10%, N 0.020%-0.030%, Co≤0.06%, Nb 0.008%-0.012%, V 0.05%-0.10%, Ti 0.008%-0.012%, and the balance is Fe and unavoidable impurities.

2. The method for manufacturing high-strength and toughness Z12CN13 martensitic stainless steel according to claim 1, characterized in that: When the high-strength and toughness Z12CN13 martensitic stainless steel is heat treated, the quenching temperature is 900-1010°C and the tempering temperature is 600-700°C.

3. The method for manufacturing high-strength and toughness Z12CN13 martensitic stainless steel according to claim 2, characterized in that: During the heat treatment of the high-strength and toughness Z12CN13 martensitic stainless steel, quenching: heating and keeping warm at 900-1010°C for 1h / 50mm, and then taking out of the furnace and oil cooling after the insulation is completed; tempering: heating and keeping warm at 600-700°C for 1-3h / 50mm, and then taking out of the furnace and air cooling after the insulation is completed.

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