Glosary corrosion

Threshold stress for stress-corrosion-cracking. The critical gross section stress at the onset of stress-corrosion cracking under specified conditions.

An accumulation of deposits. This term includes accumulation and growth of marine organisms on a submerged metal surface and also includes the accumulation of deposits (usually inorganic) on heat exchanger tubing.

The region of an anodic polarization curve, noble to and; above the passive potential range, in which there is a significant increase in current density (increased metal dissolution) as the potential becomes more positive (noble).

A group of coating or welding processes in which finely divided metallic or nonmetallic materials are deposited in a molten or semimolten condition to form a coating. The coating material may be in the form of powder, ceramic rod, wire, or molten material ...

A molecule usually an organic compound, having the ability to join with a number of identical molecules to form a polymer.

A method of fracture analysis that can determine the stress (or load) required to induce fracture instability in a structure containing a cracklike flaw of known size and shape. See also fracture mechanics and stress-intensity factor.

A stress that causes two parts of an elastic body. on either side of a typical stress plane, to pull apart. Contrast with compressive stress.

See intergranular cracking.

Stresses that remain within a body as a result of plastic deformation.

Localized corrosion of a metal surface, confined to a point or small area, that takes the form of cavities or pits.

The stress condition in linear elastic fracture mechanics in which there is zero strain in a direction normal to both the axis of applied tensile stress and the direction of crack growth (that is, parallel to the crack front); most nearly achieved in load ...

Also called solidification crackinghot cracking of weldments is caused by the segregation at grain boundaries of low-melting constituents in the weld metal. This can resultin grain-boundary tearing under thermal contraction stresses. Hot cracking can be m ...

(1) That section of pipeline extending from the ocean floor up the platform. Also, the vertical tube in a steam generator convection bank that circulates water and steam upward. (2) A reservoir of molten metal connected to a casting to provide additional ...

See biological corrosion.

Accelerated deterioration of metals in carbonaceous gases at elevated temperatures to form a dustlike corrosion product; a unique form of high temperature corrosion which forms a dust-like corrosion product and sometimes develops hemispherical pits on a s ...

Any aquatic organism with a sessile adult stage that attaches to and fouls underwater structures of ships.

Having an amenity for oil. See also hydrophilic and hydrophobic.

Heat treatment carried out in steel to reduce internal stresses.

Also called postweld heat treatment cracking, stress-relief cracking occurs when susceptible alloys are suhjected to thermal stress relief after welding to reduce residual stresses and improve toughness. Stress-relief cracking occurs only in metals that c ...