300 Series SS, 400 Series SS and duplex SS are subject to pitting and localized corrosion under insulation. In addition, __________ are also subject to SCC if chlorides are present, while _________ are less susceptible.

Hydrochloric acid corrosion is a general and localized corrosion and is very aggressive to most common materials of construction. Damage in refineries is often associated with dew point corrosion in which vapors containing _______ and hydrogen chloride condense from the overhead stream of a distillation, fractionation, or stripping tower.

Ammonium chloride salts are hydroscopic and readily absorb water. A ________ amount of water can lead to very aggressive ammonium chloride corrosion.

Corrosion in boiler feedwater and condensate return systems is usually the result of dissolved gases, oxygen and ________.

Metallic components form a surface __________ when exposed to sulfur compounds. This may react with air (oxygen) and moisture to form sulfur acids (polythionic acid).