Thick gauge q345r steel plate with excellent low-temperature impact toughness at core and manufacturing method

Abstract

The invention discloses a thick-gauge Q345R steel plate with excellent low-temperature impact toughness at the core. The steel plate has excellent low-temperature impact toughness while ensuring the strength of the steel plate by reasonably controlling the content range of C and alloy elements. Its manufacturing method adopts high-clean smelting technology, utilizes RH, LF high-efficiency refining, high-efficiency desulfurization, and precise control technology of refining slag to obtain harmful elements of P and S with low content, and obtain steel billets with high purity. Through the process of controlled rolling and controlled cold rolling + heat treatment normalizing + high temperature tempering, the heat treatment temperature of the steel plate, holding time and other parameters are precisely controlled to obtain uniform and fine ferrite + pearlite + microalloying element precipitation with excellent strength and toughness ratio Material metallographic organization. To ensure the uniformity of thick gauge steel plate in the thickness direction, especially to obtain excellent low temperature impact toughness of the core.

Description

technical field [0001] The invention relates to a steel for boiler pressure vessels and a manufacturing method thereof, in particular to a thick-gauge Q345R steel plate with excellent low-temperature impact toughness at the core and a manufacturing method thereof. Background technique [0002] In recent years, the container manufacturing industry has rapidly developed in the direction of large-scale and high-parameterization, and the demand for thick-gauge steel plates is increasing day by day. At the same time, the requirements for its related performance and quality are getting higher and higher. However, at present, steel plates for thick containers cannot fully meet the market demand, and there are the following problems: 1. There are many studies on the performance of 1 / 4 of the thickness, but less research on the performance of the core, and the low-temperature impact toughness of the core is low. It is one of the effective means to test the uniformity of thick plate t...

AI Technical Summary

Problems solved by technology

However, at present, steel plates for thick gauge containers cannot fully meet the market demand, and there are the following problems: 1. There are many studies on the performance of the 1 / 4 thickness, but less research on the performance of the core, and the low temperature impact toughness of the core is low. One of the effective means to test the uniformity of thick plate thickness direction

There are almost no mature production process solutions that can be used for reference, and it is necessary to concentrate on research and development

2. At present, the performance of the core of the thick gauge steel plate is quite different from that of the 1 / 4 of the thickness, and the performance of the core is much lower than that of the 1 / 4 of the thickness.

[0004] However, the above two inventions cannot guarantee the low-temperature impact toughness of the core of the steel plate, and cannot guarantee the uniformity of the thick-gauge steel plate in the thickness direction.

Failure to solve the existing problems of steel plates for thick gauge containers

Images