Hydrogen Blistering

Subsurface voids produced in a metal by hydrogen absorption in (usually) low strength alloys with resulting surface bulges.

Hydrogen Induced Cracking (HIC)

A form of hydrogen blistering in which stepwise internal cracks are created that can affect the integrity of the metal.

Hydrogen Ion (pH)

Refers to acidity or alkalinity of water or soil. An ion is a charged atom or group of atoms in solution or in a gas. Solutions contain equivalent numbers of positive and negative ions.

Hydrogen Stress Cracking

A cracking process that results from the presence of hydrogen in a metal in combination with tensile stress. It occurs most frequently with high strength alloys.

Hydrogen Sulfide

An odorous gas sometimes found in sewer systems. Recognizable by a rotten egg odor. Chemical formula is H2S.