... third part inspection certification: ISO Heat Exchanger Tubes Shijiazhuang pairun is manufacturer and distributor of high quality heat exchanger tubing with ... , 316L, 317, 321, 347Ferritic StainlessA-268 TP 409, 430, 439,A-268 TP 409, 430, 439TitaniumB-338 Grades 2, 7, 12, 16B-338HastelloyB ...