Corrosion-resistant steel for high-Nb crude oil cargo ship cabin base plate

Abstract

The invention discloses corrosion-resistant steel for a high-Nb crude oil cargo ship cabin base plate. The corrosion-resistant steel is used in a crude oil cargo ship cabin base corrosion environment and can reduce local corrosion on a base plate. The corrosion-resistant steel comprises one or two of 0.04-0.2% of Nb, 0.01-0.2% of C, 0.05-2% of Mn, 0.05-1% of Si, less than 0.01% of P, less than 0.01% of S, 0.01-0.6% of Ni, 0.05-0.8% of Cu, 0.01-0.5% of W, less than 0.2% of Cr, 0.002-0.4% of Mo and 0.01-0.5% of W, and the balance Fe and unavoidable impurities. The corrosion-resistant steel can be prepared by simple processes, and can form an oxide protection film on the steel surface thereby improving local corrosion resistance and corrosion resistance in a seawater spittle environment and a seawater dipping environment.

Description

technical field [0001] The invention relates to a corrosion-resistant steel for cargo tanks of crude oil tankers, especially when used as a steel material for the bottom plate of the cargo ship, which can reduce local corrosion at the bottom plate. Background technique [0002] There are a lot of chloride ions in the sewage at the bottom of the tanker's cabin, and the residual crude oil on the bottom plate forms a protective film on the surface to protect the bottom plate from corrosion. There is some sludge on the oil film, which contains a large amount of elemental sulfur. It is found through experiments that the anti-corrosion effect of the oil film is the same as that of the coating. The pitting corrosion of the bottom plate occurs at the damaged parts of the oil film, and these damaged parts come from the flushing of crude oil. Where the oil film is damaged, the bottom plate is exposed to a severe corrosive environment, forming a corroded primary battery. The damaged...

AI Technical Summary

Problems solved by technology

[0007] The anti-corrosion measures currently used are mainly coating and electrochemical anti-corrosion. However, due to the large coating area of ​​crude oil tankers and the need to re-coat once in about 10 years, the cost is very high. In addition, in the environment of the cargo tank bottom plate , the applied thick coating promotes the corrosion of the damaged part of the coating film

In addition, regular inspections are carried out on the floor, and parts with deep pitting corrosion are repaired by overlay welding, but the problem is that the maintenance cost is too high

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