ASTM A995 Gr. 6A is a material designed for high-chlorine media, with a PREN of approximately 41–44. Compared to ASTM A995 Gr. 4A and ASTM A995 Gr. 5A valves, ASTM A995 Gr. 6A valves have the following advantages:

① ASTM A995 Gr. 6A valves contain tungsten, which enhances their resistance to pitting and crevice corrosion;

② The PREN of ASTM A995 Gr. 6A valves is higher than that of ASTM A995 Gr. 4A and ASTM A995 Gr. 5A valves, therefore, ASTM A995 Gr. 6A valves have a higher critical pitting temperature for resistance to high-temperature seawater and high-chlorine brine;

③ ASTM A995 Gr. 6A valves contain Cu, which significantly improves their resistance to corrosion from dilute sulfuric acid, phosphoric acid, and acidic + chloride ion complex media.

Material Selection Tips:

① For mild chloride environments and ambient temperature seawater, ASTM A995 Gr. 4A valves are recommended.

② For high-temperature seawater and simple high-chlorine brine, ASTM A995 Gr. 5A valves are recommended.

③ For environments with coexisting high-chlorine and dilute inorganic acids, requiring higher crevice corrosion resistance, ASTM A995 Gr. 6A valves are recommended.

④ For polar cryogenic conditions, ASTM A995 Gr. 6A-G valves are recommended (with supplementary requirement S52).