... HG21634 elbow Φ45×4 20(used in British series)The material used in socket welding fitting usually are carbon steel, ... alloy steel, stainless steel, low-temperature steel, monel and nickel alloy.The socket ... Elbow, 45°Elbow, Socket weld tee, Socket-welded reducing coupling, Socket-welded full coupling, Socket-welded end cap, Socket-welded half coupling, ...