Development of Structural Damage and Cracking in a Landing Head during Long-Term Operation under North Conditions

Resumo

Abstract—The development of structural damage and cracking in a landing head used in Western Siberia is studied. The landing head is made of 20KhNL steel, which is an analog of T32MoCN8R steel produced in Romania. Crack growth is detected on the outer side of the landing head at the site of intersection of its end face with the ring surface. The experimental results obtained in this work demonstrate that the following two types of structural changes, which involve diffusion-mobile hydrogen, take place in the landing head during operation: the formation of a long chain of pores along the boundaries of the former austenite grains and the formation of ferrite bands, in which cementite particles dissolved.