Some Studies on the Sulphide Corrosion Cracking of Chromium-Molybdenum steels (Report 2)

Abstract

We have concluded already in Report 1 that embrittlement of 2 1/4% Cr-1% Mo steel caused by immersion in 0.5% acetic acid solution saturated with hydrogen sulphide can be regarded as the hydrogen embrittlement.
This report describes the influence of corrosive environment, i.e., temperature of 0.5% acetic acid and hydrogen sulphide concentration, and heat treatment on hydrogen sulphide corrosion.
In this research, we shall also try to clarify the effect of test specimen diameter on absorbed hydrogen and embrittlement.
The conclusions of this report are follows.
1. In the case of the immersion test, the volume of absorbed hydrogen is greatly dependent on the hydrogen sulphide concentration used and solution temperature more sensitive to corrosion loss.
2. The volume of absorbed hydrogen decreases with diameter of test specimen and the embrittlement caused by immersion is not related with the diameter.
3. The effect of heat treatment on the absorbed hydrogen and others, involve complex problems, so that we suppose the relation between the volume of absorbed hydrogen and corrosion loss or the mechanical properties is non-existent.