On the Hydrogen Embrittlement of a Quenched Plain Carbon Steel

Abstract

To investigate the hydrogen embrittlement of a quenched plain carbon steel, the specimens of 0·3% carbon steel were annealed at 700°C, and quenched in a martemper oil and in water.
Then, tensile tests of the specimens were carried out right after the specimens were made to absorb hydrogen through electrolysis. The volume of hydrogen which the quenched and annealed specimens absorbed was measured and the internal friction of the specimens before and after absorbing hydrogen was measured by a transversal vibrating method.
The experimental results were as follows: -
(1) The degrees of the hydrogen embrittlement of the specimens quenched in water, quenched in a martemper oil and annealed at 700°C after hot rolling, were 7·2 38·5 and 42·8% respectively, where the degree of hydrogen embrittlement was shown by { (∈₀-∈) /∈₀} ×100, and ∈0 was the reduction of area before hydrogen absorption, ∈ was the minimum value of reduction of area owing to the increasing of the volume of absorbed hydrogen in the steel.
(2) The hydrogen evolution at the room temperature was almost finished in two hours and both elongation and reduction of area recovered.
(3) Both internal frictions at the room temperature of the sample after and before hydrogen absorption were the same.