The materials used for butt-welded pipe caps include carbon steel, stainless steel, alloy steel, low-temperature steel, high-performance steel, and malleable cast iron. Carbon steel materials include ASTM/ASME A234 WPB and WPC. Alloy steel materials include ASTM/ASME A234 WP1, WP12, WP11, WP22, WP5, WP91, and WP911.
Stainless steel materials must conform to ASTM A403 standards. Commonly used grades include 304, 304L, 304H, 316, 316L, 310S, 317, 347, and 904L, as well as duplex stainless steels such as S32205 and S31803. Low-temperature steel materials include ASTM/ASME A402 WPL3 and WPL6. High-performance steel materials include ASTM/ASME A860 WPHY 42, 46, 52, 60, 65, and 70. Malleable cast iron materials include KTH330-08.