F-grade large-thickness weldable steel plate with high pureness and high low-temperature toughness and production method thereof

Abstract

The invention discloses an F-grade large-thickness weldable steel plate with high pureness and high low-temperature toughness and a production method thereof. The steel plate consists of the following components in percentage by mass: 0.10-0.20% of C, 0.15-0.55% of Si, 0.90-1.80% of Mn, P not higher than 0.03%, S not higher than 0.03%, 0.020-0.040% of Nb, 0.010-0.080% of Al, 0.035-0.085% of V, Ti not higher than 0.020%, and the balance of Fe and inevitable impurities. The method performs the production through an electroslag remelting process; the largest thickness of the steel plate can reach 500 mm; the high pureness is realized after the remelting; the interior structure of the steel plate is compact; the low-power defect control is lower; the low-power structure of the steel plate has no such defects as cracks and air holes; the looseness and segregation grades are not higher than 1.0 grade; the ultrasonic flaw detection is performed to satisfy the I-grade requirement of GB / T2970; the steel plate has the following excellent comprehensive performances: the transverse stretching, the longitudinal stretching and the impact performance are basically consistent, and the isotropy and the Z-direction performance are better; the steel plate has higher low-temperature toughness; -60 DEG C of impacting energy reaches above 27 J; and after the remelting, the variation of the main components in the steel is little, and the components are more uniform.

Description

technical field [0001] The invention relates to an F-class ultra-thick high-strength steel, in particular to a high-purity, high-low temperature toughness F-class large-thickness easy-to-weld steel plate and a production method thereof. Background technique [0002] With the rapid development of my country's marine engineering, the requirements for steel are getting higher and higher: one is high strength, the other is high toughness, and the third is good welding performance. In order to meet the growing domestic demand for marine engineering steel, it is necessary to continuously develop marine engineering steel that meets market demand. Among them, F-class ultra-thick high-strength steel is one of the high-strength, high-toughness ultra-thick steel plates that urgently need to be developed. [0003] F-grade extra-thick steel plates for marine engineering have higher requirements on the quality and performance of metal materials, especially the low-temperature toughness, w...

AI Technical Summary

Problems solved by technology

[0003] F-grade extra-thick steel plates for marine engineering have higher requirements on the quality and performance of metal materials, especially the low-temperature toughness, welding performance and Z-direction performance of steel, which have exceeded the scope of existing steel plates for marine engineering. Its thickness requirements are getting higher and higher, and the maximum thickness is close to 500mm. Under this thickness specification, ordinary smelting and casting methods cannot meet the needs, especially in terms of internal quality.

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