Baoshan Iron & Steel Co., Ltd.

Zhigang Ma

Jian Long Yang

Guodong Xu

Junkai Wang

Ruizhi Wang

Shan Gao

Caiyi Zhang

Yunan Wang

Jian Yang

A thick steel plate for high heat input welding and having great heat-affected area toughness and a manufacturing method therefor, comprising the steps of smelting, casting, rolling, and cooling. Chemical composition is properly controlled for the steel plate and satisfies 1&#x2264;Ti/N&#x2264;6 and Mg/Ti&#x3e;0.017, where effective S content in steel=S&#x2212;1.3 Mg&#x2212;0.8 Ca&#x2212;0.34 REM&#x2212;0.35 Zr, and effective S content in steel: 0.0003-0.003%; finely dispersed inclusions may be formed in the steel plate, and the amount of composite inclusion MgO+TiO+MnS in the steel plate is controlled at a proportion greater than or equal to 5%. The tensile strength of a base material so acquired is &#x2265;510 MPa, insofar as welding input energy is 200-400 kJ/cm, the average Charpy impact work of the steel plate at &#x2212;40 &#xb0; C. is 100 J or more, at the same time, the average Charpy aging impact work of the base material of &#xbd; thickness at &#x2212;40&#xb0; C. is 46 J or more.

Thick steel plate for high heat input welding and having great heat-affected area toughness and manufacturing method therefor

A thick steel plate for high heat input welding and having great heat-affected area toughness and a manufacturing method therefor, comprising the steps of smelting, casting, rolling, and cooling. Also, the chemical composition of the steel plate satisfies 1&#x2264;Ti/N&#x2264;6 and (Ca+REM+Zr)/Al&#x2265;0.11, where the effective S content in steel=S-0.8Ca-0.34REM-0.35Zr. and the effective S content in steel: 0.0006-0.005%; finely dispersed inclusions may be formed, and the amount of composite inclusion CaO+AlO+MnS+TiN in the steel plate is at a proportion of &#x2265;12%. With respect to welding in which the thickness of the steel plate is 50-70 mm, the tensile strength of a base material is &#x2265;510 MPa. and welding input energy is 200-400 kJ/cm, the average Charpy impact work of a welding heat-affected area of the steel plate at &#x2212;40&#xb0; C. is 100 J or more, and at the same time, the average Charpy aging impact work of the base material of &#xbd; thickness at &#x2212;40&#xb0; C. is 46 J or more.

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Shanghai, China

Zhigang Ma