Resistance of Tubular Materials to Sulphide-Corrosion Cracking

A typical sulphide-corrosion cracking failure of tubing in a sour gas-condensate well is described in detail. A laboratory test procedure is described which allows alloys to be rated as to their resistance to sulphide-corrosion cracking. Using this rating, based on the critical stress to cause cracking in a standard laboratory test, a study has been made of the relative susceptibility to cracking of a large number of heats of commercial tubular alloys (e.g., N-80, J-55, 5 per cent nickel steel, and 9 per cent nickel steel). It has been shown that significant improvement in the resistance to cracking of commercial N-80 tubing can be effected by means of a simple tempering heat-treatment.