High-strength hull steel with excellent low-temperature toughness and one-steel multi-level heat treatment technology of hull steel

A low temperature toughness, marine steel technology, applied in the field of metallurgy, can solve the problems of high alloy cost, different alloy composition schemes, complex production process, etc., and achieve the effects of reducing energy consumption, shortening production cycle, excellent low temperature toughness and elongation

Active Publication Date: 2018-03-16
NANJING IRON & STEEL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to solve the problems in the prior art that different strength grades and different thicknesses of marine steel require different alloy composition schemes, high alloy cost and complicated production process, and provide a

Method used

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  • High-strength hull steel with excellent low-temperature toughness and one-steel multi-level heat treatment technology of hull steel
  • High-strength hull steel with excellent low-temperature toughness and one-steel multi-level heat treatment technology of hull steel
  • High-strength hull steel with excellent low-temperature toughness and one-steel multi-level heat treatment technology of hull steel

Examples

Experimental program
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Effect test

Embodiment 1

[0019] The steel plate thickness of this embodiment is 42mm, and its chemical composition is C 0.13%, Si 0.20%, Mn 1.45%, Ni 0.12%, Cr 0.16%, Mo 0.08%, Nb 0.023%, Ti 0.014%, V≤ 0.02%, P≤0.015%, S≤0.0022%, B 0.002% and the balance Fe.

[0020] Manufacture steel slabs according to the above composition, heat the steel slabs to 1050-1150°C, control rolling to a specified thickness, air-cool to room temperature after rolling, and then conduct heat treatment. Samples are taken on finished marine steel plates, and then tensile and low temperature impact tests are performed.

[0021] The heat treatment process of the test steel is as follows:

[0022] (1) Sub-temperature quenching: Heat the test steel to 820°C, keep it warm for 50min, and then water-cool to room temperature.

[0023] (2) Tempering: Heat the sample that has been quenched and cooled to room temperature to 635°C, keep it warm for 60min, and then take it out and cool it in air.

[0024] After the above treatment, the ...

Embodiment 2

[0026] The thickness of the steel plate in this embodiment is 27 mm, and its chemical composition is the same as that in Embodiment 1.

[0027] The heat treatment process of the test steel is as follows:

[0028] (1) Sub-temperature quenching: Heat the test steel to 790°C, keep it warm for 35min, and then water-cool to room temperature.

[0029] (2) Tempering: Heat the sample that has been quenched and cooled to room temperature to 600°C, keep it warm for 45 minutes, and then take it out and air-cool it.

[0030] After the above treatment, the tempered tissue such as figure 1 As shown, it is ferrite + tempered sorbite, and the volume fraction of ferrite is 32%. The yield strength of the test steel is 521MPa, the tensile strength is 615MPa, the elongation is 22.60%, and the impact energy absorbed at -40°C is 218 / 216 / 215J respectively, which can meet the requirements of E460 strength grade.

Embodiment 3

[0032] The thickness of the steel plate in this embodiment is 50mm, and its chemical composition is C 0.12%, Si 0.24%, Mn 1.56%, Ni 0.14%, Cr 0.23%, Mo 0.09%, Nb 0.025%, Ti 0.012%, V≤ 0.02%, P≤0.015%, S≤0.002%, B 0.0027% and the balance Fe.

[0033] Manufacture steel slabs according to the above composition, heat the steel slabs to 1050-1150°C, control rolling to a specified thickness, air-cool to room temperature after rolling, and then conduct heat treatment. Samples are taken on finished marine steel plates, and then tensile and low temperature impact tests are performed.

[0034] The heat treatment process of the test steel is as follows:

[0035] (1) Sub-temperature quenching: Heat the test steel to 790°C, keep it warm for 60min, and then water-cool to room temperature.

[0036] (2) Tempering: Heat the sample that has been quenched and cooled to room temperature to 560°C, keep it warm for 90 minutes, and then take it out and air-cool it.

[0037] After the above treatm...

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Abstract

The invention provides high-strength hull steel with excellent low-temperature toughness and a one-steel multi-level heat treatment technology of the hull steel. The hull steel comprises the chemicalcomponents of, by mass, 0.12-0.15% of C, 0.20-0.30% of Si, 1.40-1.70% of Mn, 0.12-0.15% of Ni, 0.16-0.25% of Cr, 0.08-0.12% of Mo, 0.020-0.030% of Nb, 0.012-0.018% of Ti, less than or equal to 0.02% of V, less than or equal to 0.015% of P, less than or equal to 0.002% of S, 0.0020-0.0030% of B and the balance Fe and unavoidable impurities. According to the technology, a high-strength hull steel plate with excellent low-temperature toughness can be produced by combining different quenching technologies with the tempering technology, wherein the maximum thickness of the hull steel plate is 50 mmand the hull steel plate can meet the requirement of E460-E550 strength levels. The alloy cost is low, and the technology adaptability is wide. The high-strength hull steel with the excellent low-temperature toughness and the one-steel multi-level heat treatment technology of the hull steel solve the problems that different components are needed by the steel plates with different steel levels anddifferent thicknesses, and production organization is difficult. Flexible manufacturing of one-steel and multi-level is achieved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to marine steel and its heat treatment process, in particular to a high-strength, excellent low-temperature toughness marine steel and its multi-stage heat treatment process for one steel. Background technique [0002] After entering the 21st century, with the development of science and technology and economic globalization, more and more attention has been paid to the development of marine resources and marine transportation. In the shipbuilding industry, in 2010, China's shipbuilding completions accounted for 41.9% of the world market share, new orders accounted for 48.5% of the world market share, and orders in hand accounted for 40.8% of the world market share, all ranking first in the world. China has already Become the shipbuilding center of the world. The rapid development of the marine engineering equipment manufacturing industry has provided opportunities for the upstream...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58C21D1/18C21D6/00
CPCC21D1/18C21D6/004C21D6/005C21D6/008C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58C21D1/185
Inventor 谢章龙陈锋王攀峰靳星张丙军王兆华胡其龙
Owner NANJING IRON & STEEL CO LTD
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