Hydrogen Induced Cracking(HIC)

Metal materials play a key role in the manufacture of industrial components and equipment due to specific mechanical properties such as strength, stiffness, toughness, and high-temperature resistance. But for more than 100 years, the effect of hydrogen has been proven to dramatically reduce the fracture toughness of advanced alloys (it has been seen in modern steels that crack growth is expected to be one-tenth of the fracture toughness). Hydrogen induced cracking (HIC) is caused by the penetration of hydrogen atoms into the metal crystal lattice, often in the heat-affected zone (HAZ). The entrapment of hydrogen atoms in the material undermines the mechanical properties of the material. It also creates cavities in the metal that reduce its flexibility and tensile strength and can lead to cracking and eventually fracture.

Hydrogen Induced Cracking(HIC) is found in plain carbon steels and low strength alloy steels (HSLA), with other names such as Cold Cracking, Toe Cracking, and Under Bead, cracking is also known. Indicates the different naming of the crack location and its timing (which can occur up to 72 hours after welding). $brittle fracture$

Pressure vessels serving acidic environments (especially refineries) can be at risk of hydrogen cracking due to the introduction of hydrogen into the material. The risk associated with the specific working conditions and quality of the steel used in the construction of the pressure tank must be properly managed to ensure maximum safety with minimum cost.

Nowadays, the usual management strategy is based on Risk-Based Inspection or RBI, which defines a specific inspection plan followed by the Fitness-for-Service (FFS) method, the ability to continue equipping the service using methods such as check failure mechanics. Is coming.