Effect of Temperature on Hydrogen Environment Embrittlement of Carbon Steels at Low Temperatures

Abstract

Hydrogen environment embrittlement (HEE) of carbon steels (SUY, S15C and S35C) was investigated at the temperature range from 300 to 100 K with the strain rate of 4.2 × 10-5 s-1 by using specially designed equipment. The results obtained are as follows. (1) HEE increased with decreasing temperature, reached a maximum at around 200 K, and then decreased rapidly with decreasing temperature. HEE of the materials increased in order of SUY, S15C and S35C at 200 K. The minimum HEE temperature of S35C was higher than that of S15C and SUY. (2) Hydrogen induced cracking on the surface of the specimen enhanced cleavage fracture. It is considered that HEE of the carbon steels from 300 K to the maximum HEE temperature depended on the sensitivity of the cleavage fracture and the behavior below the maximum HEE temperature depended on the diffusion of hydrogen.