EFFECT OF HIGH PRESSURE HYDROGEN ENVIRONMENT ON FATIGUE CRACK GROWTH RATE PROPERTIES OF STRUCTURAL STEEL USED FOR CYLINDERS

Paper deals with evaluation of effect of high pressure hydrogen environment with actual pressure of hydrogen up to 30 MPa on fatigue crack growth rate properties of structural steel used for cylinders production. 34CrNiMo6 grade steel was used for experimental programme. A unique new testing equipment (hydrogen autoclave) was built in MATERIAL & METALLURGICAL RESEARCH, Ltd. to study degradation mechanism of high pressure hydrogen environment on mechanical properties including fracture mechanics properties of structural materials. There is comparison of results of crack growth rate in the air and high pressure hydrogen presented in the paper. Potential method was used for crack growth monitoring in the hydrogen autoclave due to cycling. Effect of hydrogen is presented on fractography examination, change in fracture morphology was found on fracture surfaces of tested specimens due to presence of high pressure hydrogen.