An ultra-high-strength tempered marine steel plate with excellent low-temperature performance and its manufacturing method

Abstract

The invention discloses an ultra-high-strength tempered marine steel plate with excellent low-temperature performance and a manufacturing method thereof. Steel contains: C: 0.07% ~ 0.12%; Si: 0.15% ~ 0.40%; Mn: 1.15% ~ 1.60%; P≤0.012%; S≤0.002%; Ni: 0.15% ~ 0.50%; Cr≤0.2% ; or one of V≤0.040%; Mo: 0.10% to 0.25%; Ti: 0.008% to 0.025%; Alt: 0.015% to 0.040%, and the balance is iron and unavoidable impurities. The slab soaking temperature is 1130-1180°C, the first-stage rolling temperature is 1050-1150°C, the rolling speed of the first two passes is ≤1.2m / s, and the single-pass reduction rate is ≥15%, and the second-stage rolling is started Temperature ≤890°C, final rolling temperature ≥800°C; quenching temperature 880-910°C, heat preservation 20-40min; tempering temperature 600-630°C, total furnace time 3.5-4min / mm*slab thickness. Steel plate has excellent low temperature performance.

Description

technical field [0001] The invention belongs to the field of iron and steel material preparation, and particularly relates to a quenched and tempered marine steel plate with a yield strength of over 420 MPa and excellent low-temperature performance and a manufacturing method thereof. Background technique [0002] As a key structural material for offshore engineering equipment, steel is widely used in offshore wind power, production platforms and submarine pipelines. The service environment of steel plates for offshore structures is harsh, not only to withstand gravity loads, but also to withstand wind loads, wave loads, current loads, ice loads, and seismic loads, and the service life of marine engineering equipment is 50% longer than that of ships. The requirements are extremely high, and the steel plates used are gradually developing towards high strength, high toughness, easy weldability, good corrosion resistance, and large thickness and large size. [0003] 420MPa grad...

AI Technical Summary

Problems solved by technology

However, its C element content is too high, which is not conducive to welding

Images