A 450mpa grade hydrogen-induced cracking-resistant steel plate for pressure vessels and its production method

Abstract

The invention relates to a 450MPa-grade hydrogen-induced-cracking-resistant pressure vessel steel plate and a production method thereof, belonging to the field of pressure vessel steel plates. The steel plate comprises the following chemical components in percentage by weight: 0.13%-0.14% of C, 0.20%-0.30% of Si, 0.90%-0.95% of Mn, at most 0.008% of P, at most 0.001% of S, and the balance of Fe and inevitable impurities. The reasonable addition of the three alloy elements C, Si and Mn is matched with a corresponding rolling technique, and normalizing heat treatment is performed; and thus, on the premise of satisfying the mechanical properties of the common pressure vessel steel, the yield strength is greater than or equal to 300MPa, the tensile strength is greater than or equal to 450MPa, the elongation percentage is greater than or equal to 30%, and the 0 DEG C ballistic work is greater than or equal to 200J; the steel plate has favorable hydrogen induced cracking resistance; and the crack length ratio is smaller than or equal to 5%, the crack width ratio is smaller than or equal to 1.5%, and the crack sensitivity is smaller than or equal to 0.2%. The production method has the characteristics of short manufacturing process and low production cost.

Description

technical field [0001] This patent relates to steel plates for pressure vessels, in particular to a steel plate for pressure vessels with a tensile strength of 450 MPa and a production method thereof. Background technique [0002] In the field of petrochemical industry, some problems occurred in recent years due to H 2 There are equipment damage or rupture accidents in S, which makes people for H 2 The hydrogen-induced cracking (HIC) performance of pressure vessel steel plates used in S corrosive environments is required. Hydrogen cracking is a common damage form of steel in wet hydrogen sulfide environment, H 2 The hydrogen atoms produced by the reaction between S and the steel surface, the hydrogen atoms diffuse into the steel, may accumulate in the steel inclusions, grain boundaries, dislocations, etc. to form hydrogen gas and initiate cracks. When there is a banded structure in the steel, the cracks are easy Expand along the banded tissue to form larger size cracks. ...

AI Technical Summary

Problems solved by technology

Compared with the continuous casting slab commonly used in modern steel mills, the steel ingot is beneficial to the control of the center segregation of the final steel plate and the band structure in the center, but it has the disadvantages of low production efficiency and low yield, and the ingot is cast in the medium and thick plate. The penetration rate among production enterprises is low, and it cannot become an economical production method for ordinary steel mills

And this patent does not have a clear index for the hydrogen-induced cracking resistance of the steel plate

Images