A Weldable Cast Steel with Large Wall Thickness

Abstract

The invention provides a welding cast steel with a high wall thickness, which is characterized by comprising the chemical components by weight as follows: 0.07 to 0.12% of C, 0.15 to 0.40% of Si, 0.6 to 1.0% of Mn, not greater than 0.015% of S, not greater than 0.020% of P, 1.5 to 1.8% of Ni, not greater than 0.30% of Cr, 0.8 to 1.2% of Cu, and the balance of Fe and inevitable impurities. According to the cast steel, the equivalent test block with the thickness being 300 mm is subject to performance test, and the part at 1 / 4 wall based on the thickness can reach the yield strength as Rp 0.2 more than or equal to 370 MPa, and the tensile strength Rm not less than 490 MPa, and the percentage A of area reduction not less than 20%, and the percentage Z of elongation not less than 40%, and the plasticity and the toughness, specifically the low-temperature impacting toughness is superior, wherein Kv2 is more than or equal to 27J at minus 40 DEG C. The welding cast steel with high wall thickness has superior welding performance, and can carry out tailored welding among castings; and the welding cast steel with high wall thickness is suitable for building a ship structure.

Description

technical field [0001] The invention relates to a steel casting technology, in particular to a weldable cast steel with large wall thickness. Background technique [0002] Cast steel is an indispensable supporting material in hull structural steel materials, mainly used for reinforcement of hull openings, sea holes, cable holes, etc. . At present, the hull structural steel cast steel in use in my country includes carbon steel cast steel such as ZG230-450H in GB11352 "Casted Carbon Steel Parts for General Engineering", etc., and low alloy and alloy cast steel such as 604, 607, QZ785, etc., and the yield strength level Covering 230MPa~785MPa. However, most of the above-mentioned cast steels have a small maximum allowable wall thickness (no more than 150mm) or no maximum allowable wall thickness. Large-walled castings such as the stern shaft frame are usually made of low-strength grade ZG230-450H, and the performance test samples are usually taken from the plum blossom bar or...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a weldable cast steel with a large wall thickness, to solve the shortage of the existing cast steel with a relatively small maximum allowable wall thickness (not greater than 150mm), and to develop a wall thickness not less than 300mm, which can meet the needs of large Requirements of ships for high-strength, large-wall-thickness cast steel