Low-alloy super-strength steel and heat treatment technique for the same

Abstract

A kind of low alloy martensite steel with high strength, the character of it is the component range as following, quality percent: C0.3-0.6,Mn0.8-2.0,i0.1-0.4,r0.8-2.0,o0.1-0.4,l1.0-2.5,S<0.0l,P<0.01, the other is Fe. The steel will be stabilized after quenching and backfire at low temperature. The low alloy steel in this patent, can own very high strength and certain tenacity after a simple heat treatment, as a result the cost of it is lower.

Description

Technical field:

[0001] The invention relates to metal materials, and in particular provides metal materials that can be used to make various precision bearing parts and structural parts with ultra-high strength requirements. technical background:

[0002] C mn Si Cr Mo Ni S P 0.42～0.48 0.5～1.0 0.25～0.35 0.9～1.2 0.15～0.35 1.5～2 ＜0.01 ＜0.01

[0003] Some data show that the tensile strength of this material can reach about 2000MPa after heat treatment. However, the inventors found that the tensile strength of 40CrNiMo and 40CrNiMoA after heat treatment (quenching + low temperature tempering) could not reach 2000MPa without liquid nitrogen cryogenic treatment, so their performance could not meet the application requirements. Invention content:

[0004] The purpose of the present invention is to provide a new low-cost low-alloy ultra-high-strength steel. This low-alloy ultra...

Examples

Embodiment 1

[0016] The material is purified and smelted in a vacuum induction furnace. The material composition is C0.35, Mn2.0, Si0.4, Cr2.0, Mo0.4, Al2.0, S0.005, P0.008, and Fe balance. After the ingot is forged, heat treatment is carried out, adopting the process of quenching + low temperature tempering, and then stabilizing aging treatment. The quenching temperature is 850°C, the quenching medium is water, the tempering temperature is 150°C, the tempering time is 1.5h, and the aging temperature is 100°C. , aging time 5h. Tensile properties after heat treatment σ b =2018MPa, σ s =1780MPa, δ(%)=10.2, φ(%)=48.3, impact energy α k = 30J. While having high strength, the material does not break until it is bent to an angle close to 120 degrees (as shown in Figures 1 and 2), indicating that the material also has good plasticity. The ingot is forged into bars of various specifications. The forging process shows that the material has good forgeability and high forging quality can be obtai...

Embodiment 2

[0018] The material is purified and smelted in a vacuum induction furnace. The material composition is C0.40, Mn1.5, Si0.27, Cr1.5, Mo0.33, Al1.8, S0.003, P0.0021, and Fe balance. The heat treatment of the forged sample adopts the process of quenching + low temperature tempering, and then stabilizing aging treatment. The quenching temperature is 880°C, the quenching medium is water, the tempering temperature is 200°C, the tempering time is 2h, and the aging temperature is 120°C. The aging time is 5h. Tensile properties after heat treatment σ b =2120.3MPa, σ s =1856MPa, δ(%)=10.8, φ(%)=47.4, impact energy α k =22J. . The ingot is forged into bars of various specifications. The forging process shows that the material has good forgeability and high forging quality can be obtained, which guarantees the performance of the forged material. The forged material is annealed at 600°C, and the hardness after annealing is HRC36-37, which can ensure good machinability.

Embodiment 3

[0020] The material is purified and smelted in a vacuum induction furnace. The material composition is C0.45, Mn1.2, Si0.3, Cr0.79, Mo0.25, Al1.5, S0.0031, P0.0022, and Fe balance. The heat treatment of the forged sample adopts the process of quenching + low temperature tempering, and then stabilizing aging treatment. The quenching temperature is 900°C, the quenching medium is oil, the tempering temperature is 250°C, the tempering time is 1.5h, and the aging temperature is 150°C. The aging time is 5h. Tensile properties after heat treatment σ b =2017MPa, σ s =1774MPa, δ(%)=9.8, φ(%)=42.4, impact energy α k =24J. . The ingot is forged into bars of various specifications. The forging process shows that the material has good forgeability and high forging quality can be obtained, which guarantees the performance of the forged material. The forged material is annealed at 600°C, and the hardness after annealing is HRC36-37, which can ensure good machinability.

Technical field:

[0001] The invention relates to metal materials, and in particular provides metal materials that can be used to make various precision bearing parts and structural parts with ultra-high strength requirements. technical background:

[0002] C mn Si Cr Mo Ni S P 0.42～0.48 0.5～1.0 0.25～0.35 0.9～1.2 0.15～0.35 1.5～2 ＜0.01 ＜0.01

[0003] Some data show that the tensile strength of this material can reach about 2000MPa after heat treatment. However, the inventors found that the tensile strength of 40CrNiMo and 40CrNiMoA after heat treatment (quenching + low temperature tempering) could not reach 2000MPa without liquid nitrogen cryogenic treatment, so their performance could not meet the application requirements. Invention content:

[0004] The purpose of the present invention is to provide a new low-cost low-alloy ultra-high-strength steel. This low-alloy ultra...

Examples

Embodiment 1

[0016] The material is purified and smelted in a vacuum induction furnace. The material composition is C0.35, Mn2.0, Si0.4, Cr2.0, Mo0.4, Al2.0, S0.005, P0.008, and Fe balance. After the ingot is forged, heat treatment is carried out, adopting the process of quenching + low temperature tempering, and then stabilizing aging treatment. The quenching temperature is 850°C, the quenching medium is water, the tempering temperature is 150°C, the tempering time is 1.5h, and the aging temperature is 100°C. , aging time 5h. Tensile properties after heat treatment σ b =2018MPa, σ s =1780MPa, δ(%)=10.2, φ(%)=48.3, impact energy α k = 30J. While having high strength, the material does not break until it is bent to an angle close to 120 degrees (as shown in Figures 1 and 2), indicating that the material also has good plasticity. The ingot is forged into bars of various specifications. The forging process shows that the material has good forgeability and high forging quality can be obtai...

Embodiment 2

[0018] The material is purified and smelted in a vacuum induction furnace. The material composition is C0.40, Mn1.5, Si0.27, Cr1.5, Mo0.33, Al1.8, S0.003, P0.0021, and Fe balance. The heat treatment of the forged sample adopts the process of quenching + low temperature tempering, and then stabilizing aging treatment. The quenching temperature is 880°C, the quenching medium is water, the tempering temperature is 200°C, the tempering time is 2h, and the aging temperature is 120°C. The aging time is 5h. Tensile properties after heat treatment σ b =2120.3MPa, σ s =1856MPa, δ(%)=10.8, φ(%)=47.4, impact energy α k =22J. . The ingot is forged into bars of various specifications. The forging process shows that the material has good forgeability and high forging quality can be obtained, which guarantees the performance of the forged material. The forged material is annealed at 600°C, and the hardness after annealing is HRC36-37, which can ensure good machinability.

Embodiment 3

[0020] The material is purified and smelted in a vacuum induction furnace. The material composition is C0.45, Mn1.2, Si0.3, Cr0.79, Mo0.25, Al1.5, S0.0031, P0.0022, and Fe balance. The heat treatment of the forged sample adopts the process of quenching + low temperature tempering, and then stabilizing aging treatment. The quenching temperature is 900°C, the quenching medium is oil, the tempering temperature is 250°C, the tempering time is 1.5h, and the aging temperature is 150°C. The aging time is 5h. Tensile properties after heat treatment σ b =2017MPa, σ s =1774MPa, δ(%)=9.8, φ(%)=42.4, impact energy α k =24J. . The ingot is forged into bars of various specifications. The forging process shows that the material has good forgeability and high forging quality can be obtained, which guarantees the performance of the forged material. The forged material is annealed at 600°C, and the hardness after annealing is HRC36-37, which can ensure good machinability.

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