50-75 mm-thick 355MPa-grade fracture toughness protecting steel and production method thereof

A technology of fracture toughness and production method, applied in the field of steel material production, can solve the problems of reduced, difficult, and improved welding performance of steel, and achieve the effects of ensuring low-temperature impact performance, stable production process, and strong operability

Inactive Publication Date: 2015-01-07
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, when the production method of hot rolling process is adopted, it is not conducive to the improvement of the strength and toughness of large-thickness steel; while the method of normalizing usually obtains ferrite

Method used

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  • 50-75 mm-thick 355MPa-grade fracture toughness protecting steel and production method thereof
  • 50-75 mm-thick 355MPa-grade fracture toughness protecting steel and production method thereof
  • 50-75 mm-thick 355MPa-grade fracture toughness protecting steel and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The steel plate includes the following chemical composition in weight percent: C 0.06%, Si 0.25%, Mn 1.51%, P 0.013%, S 0.002%, Ni 0.41%, Nb 0.045%, V 0.026%, Ti 0.012%, the balance Fe and unavoidable impurities. The final microstructure of the steel plate is quasi-polygonal ferrite and bainite.

[0023] The 355MPa fracture toughness guarantee steel includes the following steps: KR hot metal desulfurization pretreatment→converter smelting→deoxidation alloying→CAS refining→LF refining→RH treatment→CCM continuous casting→slab slow cooling for 48h→slab reheating→ Descaling with high-pressure water → controlled rolling → straightening → cooling → cutting, sampling → inspection → spray number printing → storage.

[0024] Among them (1) smelting: hot metal desulfurization ≤ 0.003%; RH refining pure degassing time not less than 6 minutes; soft blowing after RH refining pure degassing is not less than 20 minutes, calcium treatment after vacuum treatment, continuous casting tun...

Embodiment 2

[0031] The steel plate includes the following chemical composition in weight percentage: C 0.07%, Si 0.30%, Mn 1.45%, P 0.011%, S 0.004%, Ni 0.32%, Nb 0.035%, V 0.031%, Ti 0.011%, the balance Fe and unavoidable impurities.

[0032] The 355MPa fracture toughness guarantee steel includes the following steps: KR hot metal desulfurization pretreatment→converter smelting→deoxidation alloying→CAS refining→LF refining→RH treatment→CCM continuous casting→slab slow cooling for 48h→slab reheating→ Descaling with high-pressure water → controlled rolling → straightening → cooling → cutting, sampling → inspection → spray number printing → storage.

[0033]Among them (1) smelting: hot metal desulfurization ≤ 0.003%; RH refining pure degassing time not less than 6 minutes; soft blowing after RH refining pure degassing is not less than 20 minutes, calcium treatment after vacuum treatment, continuous casting tundish target temperature The temperature is 1525~1540℃, and the casting speed is st...

Embodiment 3

[0038] The steel plate includes the following chemical composition in weight percentage: C 0.085%, Si 0.45%, Mn 1.35%, P 0.014%, S 0.002%, Ni 0.38%, Nb 0.020%, V 0.028%, Ti 0.015%, the balance Fe and unavoidable impurities.

[0039] The 355MPa fracture toughness guarantee steel includes the following steps: KR hot metal desulfurization pretreatment→converter smelting→deoxidation alloying→CAS refining→LF refining→RH treatment→CCM continuous casting→slab slow cooling for 48h→slab reheating→ Descaling with high-pressure water → controlled rolling → straightening → cooling → cutting, sampling → inspection → spray number printing → storage.

[0040] Among them (1) smelting: hot metal desulfurization ≤ 0.003%; RH refining pure degassing time not less than 6 minutes; soft blowing after RH refining pure degassing is not less than 20 minutes, calcium treatment after vacuum treatment, continuous casting tundish target temperature The temperature is 1525~1540℃, and the casting speed is ...

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Abstract

The invention belongs to the technical field of steel and iron material production and particularly relates to 50-75 mm-thick 355MPa-grade fracture toughness protecting steel and a production method thereof. The 50-75 mm-thick 355MPa-grade fracture toughness protecting steel comprises the following chemical components in percentage by weight: 0.04-0.13 percent of C, 0.2-0.5 percent of Si, 1.0-1.6 percent of Mn, less than 0.018 percent of P, less than 0.005 percent of S, 0.3-0.7 percent of Ni, 0.02-0.05 percent of Nb, 0.02-0.04 percent of V, 0.08-0.020 percent of Ti and the balance of Fe and inevitable impurities. The 50-75 mm-thick 355MPa-grade fracture toughness protecting steel and the production method thereof have the benefits that the fracture toughness protecting steel is low in cost, is easy to weld and can reach 75 mm thickness under the condition of realizing 355MPa-grade high toughness of the steel; the CTOD (Crack Tip Opening Displacement) characteristic value of a welded joint at a temperature of 10 DEG C blew zero can be ensured, and the fracture toughness protecting steel with high strength, high toughness and high fracture toughness is realized under the condition of low carbon content.

Description

technical field [0001] The invention belongs to the technical field of iron and steel material production, and in particular relates to a 50-75mm thick 355MPa fracture toughness guaranteed steel and a production method thereof. Background technique [0002] Marine rights and interests are one of the core interests of our country. In recent years, the implementation of the national marine strategy has made marine engineering the focus of construction and development, and has gradually developed from the offshore to the deep sea. The rapid development of the ocean engineering equipment industry will create a huge demand for steel for ocean engineering, especially with the large-scale, high-parameterization, and lightweight of ships, ocean engineering, port machinery, and submarine oil pipelines, the performance of steel is raised. higher and higher requirements. Through the analysis of accidents in marine engineering equipment, people realized that only relying on the high st...

Claims

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Application Information

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IPC IPC(8): C22C38/14C21D8/02
CPCC22C38/04C21D8/0221C22C38/08C22C38/12C22C38/14
Inventor 徐洪庆刘晓东王焕洋李旺生李敏朱延山王南辉王勇
Owner SHANDONG IRON & STEEL CO LTD
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