JIS G3461 Japanese Industrial Standard specifies the carbon steel tubes, hereinafter refered to as the "tubes", used for excahnging heat on the inside and outside of the tube, such as water tubes, smoke tubes, superheater tubes, air preheater tubes, etc. of the boiler, and heat exchanger tubes, condenser tubes, catalyser tubes, etc. used in chemical and petroleum inudstries.JIS G3461 standard main steel grade:STB510,STB410 and so on.