Download or read book Hydrogen Attack of Steel. Progress Report, April 1, 1978--March 31, 1979 written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Four normalized carbon steels made in different ways (Si-killed, Al-killed, REM-treated, and electroslag refined) were studied to determine the role of differing fine inclusions on the early stages of hydrogen attack (HA). Hydrogen exposures were made at 450°C (6.5 MPa) and 375°C (7.6 MPa). The first stage of HA is shown to be the development of a closely spaced (1-2 .mu.m) array of small bubbles over the ferrite/pearlite, or occasionally the ferrite/ferrite boundaries. These grew together to form tears, primarily in the rolling plane, leading to more rapid expansion normal to this plane. The planes of separation followed high solute layers in banded steel but only rarely did the fracture surfaces follow inclusions. At 450°C REM-treated steel was attacked the fastest and the Al-killed steel took two to four times as long for attack.