What is abbrevialtion for carbon steel grade wpb wcb wpl6?

Answer 1

weldable made from pipe (WP), with equivalent grade B;

weldable made from casting (WC), with equivalent grade B;

weldable made from pipe, low temperature service, with 60ksi strength (WPL6)

Answer 2

WPB - Carbon steel grade, standard grade for fittings WCB - Carbon steel grade, commonly used for valves and flanges WPL6 - Low temperature carbon steel grade, used for fittings in low temperature applications