There are three factors that contribute to hydrogen-induced cracking(HIC). These factors are:

• Threshold level of hydrogen
• Susceptible microstructure
• Restraint level

In order to assess the resistance of pipe and pressure vessel steel to hydrogen induced cracking, standard tests shall be carried out in accordance with NACE TM0284.Steel specimens shall be immersed in a test solution at 25±3 ° C [77±5 ° C].

There are two standard test solutions: solution A- a sodium chloride, acetic acid (NaCl, CH3COOH) saturated H2S at ambient temperature and pressure;Solution B – a saturated H2S synthetic seawater solution at ambient temperature and pressure.The test lasted 96 hours.After the test, the specimen was removed from the test solution and the cracks were measured.Three main parameters need to be calculated to evaluate the HIC resistance of the steel: crack sensitivity ratio (CSR), crack length ratio (CLR) and crack thickness ratio (CTR).

Haihao Group supplies a variety of HIC-resistant steels for piping industry. These steels includes API 5L Grade X60, X65, X70; ASTM A516 Grade 60, 65, 70; ASTM A420 Gr. WPL6; ASTM A333 Gr.6; ASTM A860 WPHY60, WPHY65, WPHY70; ASTM A694 Gr. F60, F65, F70, etc.