At elevated temperatures, dissimilar weld metal cracking is aggravated by the diffusion of carbon out of the weld metal and into the base metal. The temperature at which carbon diffusion becomes a concern is above ________.

Refractory anchors must be resistant to __________ in high temperature services.

If weld repairs are required, the effects of temper embrittlement can be temporarily reversed (de- embrittled) by heating at ______ for 2 hours per inch of thickness and rapidly cooling to room temperature.

__________ is a form of cracking that results when certain molten metals come in contact with specific alloys. Cracking can be very sudden and brittle in nature.

HCL acid corrosion is found in several units, especially _______ and ________, units, hydroprocessing units and catalytic reformer units.