... diameter: 6-830mm 304 bright annealing seamless steel tube1: 201, TP304, 304L, 316L, TP316L, 316Ti, 317, 317L, 321 etc. 2. Technical standinox ... are authenticated by ISO9001: 2000. The main materials are 201, 304, 304L, 321, 316, 316L, 317, 310s and so on. The specification ... , heat-exchanger, pressure containers, water resources and electricity industry etc.1 304 bright annealing seamless steel tube