Testing the resistance of welds in low-alloy steels to hydrogen-induced stress corrosion cracking

The susceptibility to sulphide stress cracking of low alloy steels

“…At this temperature, the diffusion rate of carbon was so high that the cooperative growth of ferrite and cementite could take place by transporting carbon atoms from ferrite into cementite, resulting in a ferrite-pearlite microstructure. The banded microstructure for steel A is a preferential site for HIC [12]. On the other hand, chromium and molybdenum in steel B suppressed carbon diffusion by lowering the temperature transformation and promoting the formation of bainite/martensite microstructure (Fig.…”

“…Concerning effects of hydrogen trapping on embrittlement, Pressouyre [10] suggests that a greater density of sulphide inclusions in steel can be beneficial in circumstances where the content of hydrogen at potential cracking sites is lowered by uniform distribution of hydrogen over an increased number of sulphides or by delayed arrival of hydrogen to the craking sites. In contrast, a number of studies on HIC and blistering in line-pipe steels have shown [11,12] that an increase in sulphur content is detrimental because cracks are usually nucleated at elongated sulphides, and more cracks are developed in high sulphur than in low sulphur steels.…”

Влияние Металлургических Факторов На Коррозионное Растрескивание Под Напряжением Различных Сталей В Агрессивной Хлоридно-Сульфидной Среде

“…На рис. 1-5 в полулогарифмических координатах представлены зависимости времени до разрушения от величины растягивающего напряжения, нормированного на условный предел текучести для сталей разного класса при их испытании в растворе NACE при 25 • C (стандарт MR-01-75, 5%NaCl, pH = 3.5, H 2 S до насыщения) [13][14][15][16][17][18][19][20]. Из приведенных данных видно, что для всех типов сталей кривые коррозионного растрескивания под напряжением состоят из двух участков.…”