Sulfide Corrosion Cracking Of High Strength Bolting Material

The sulfide corrosion cracking behavior of Type 4140 bolts was studied in H2S-H2O systems at temperatures of 20 to 120 C and at pressures of 1 to 17 atmospheres. The susceptibility to cracking increased with increasing bolt hardness, increasing applied stress, increasing amounts of plastic deformation, and decreasing test temperature. Other bolting materials such as Inconel, Inconel-X, K-Monel, and annealed Type 316 stainless steel were completely resistant to sulfide corrosion cracking. The use of protective metallic coatings and the addition of corrosion inhibitors to the test system were evaluated as means of preventing the sulfide corrosion cracking of Type 4140 bolts. The sulfide corrosion cracking of Type 4140 bolts is believed to be best explained on the basis of hydrogen embrittlement. 3.2.2