HIC Resistant Steel Plate – ASME SA516 HIC/ ASTM A516 HIC

Hydrogen Induced Cracking (HIC) damage occurs when atomic hydrogen, generated by corrosive processes in wet H₂S (sour) environments, diffuses into steel. It can recombine into molecular hydrogen at inclusions or imperfections, creating immense internal pressure that causes stepwise cracking within the plate. This can lead to catastrophic failure of critical assets such as pressure vessels, pipelines and heat exchangers.

HIC testing is a standardised laboratory procedure that evaluates a steel plate’s resistance to Hydrogen Induced Cracking. Test coupons are exposed to a saturated H₂S solution for a set duration (typically 96 hours). After exposure, they are examined to measure crack sensitivity ratios (CLR, CTR, CSR). Passing this test certifies the material as HIC resistant.

The primary difference is the governing body and designation:

• ASTM A516 is the material specification set by ASTM International, defining the chemical, mechanical and manufacturing requirements for pressure vessel plates.
• ASME SA516 is the ASME (American Society of Mechanical Engineers) code designation that adopts and incorporates the ASTM A516 specification for use in ASME Boiler and Pressure Vessel Code construction. For practical purposes, the chemistry and mechanics are identical, but an SA prefix is often required for coded pressure equipment.

No, but they are closely linked. ASTM develops technical material specifications (such as A516). ASME develops design, fabrication and inspection codes for equipment (such as the Boiler & Pressure Vessel Code). ASME often adopts ASTM specifications, prefixing them with ‘S’ (e.g. SA516) for use in their codes. You must specify the correct designation for your application.

SA 516 steel is a carbon steel specification for pressure vessel plates, designated for use in ASME code construction. It is known for its excellent notch toughness and is commonly used in welded boilers and pressure vessels. Grades 60, 65 and 70 denote minimum yield strength (ksi). When combined with  HIC testing and controlled manufacturing process, it becomes SA516 HIC resistant steel.