ASTM A178 standard referes to electric-resistance-welded tubes with minimum-wall-thickness. Materials are carbon steel and carbon-manganese steel, ASTM A178 pipe and tube is to be used in boiler tubes, boiler flues, superheater flues and safe ends. Steel Grades A (low-carbon steel), C (medium-carbon steel), or D (carbon-manganese steel). Manufacturing processes must include heat treatment, welding after cooling. Crush test shall be performed if required by customer.