International Specification & Standards of Industrial Steel Pipe Fittings, Flanges KS : KOREAN INDUSTRIAL STANDARDS KS B 1522: Steel Butt Welding Pipe Fittings for Oidinary use and Fuel Gas. KS B 1541: Steel Butt Welding Pipe Fittings KS B 1542: Steel Socket Welding Pipe Fittings. KS B 1543: Steel Plate Butt Welding Pipe Fittings. JIS […]