Boiler steel pipes have two open ends with hollow section, which are classified into seamless steel pipe and welded steel pipe. We use the size, for example diameter, length and wall thickness to show the specification of boiler pipe. Boiler steel pipe has a big size range, from the tiny pipe with very small diameter to large pipe with several meters diameter. Steel pipe can be applied to pipeline, thermal equipment, mechanical industry, petroleum exploration, chemical industry, etc.

Classifications of steel pipe: steel pipes are classified into seamless steel pipe and welded steel pipe. There are circular pipe and special section pipe based on section configuration. Round tubes are widely used, but there are also other tubes with shapes of square, rectangle, semicircle, hexagon, equilateral, triangle and octangle.

Those steel pipe which needs to bear force coming from liquid are required to take hydraulic test in order to check the pressure-resistant ability and quality. If the pipes don't leak, soak, swell under a certain pressure, they will be qualified. Some of the steel pipes need to have flanging test, expanding test and flattening test according to buyers' requirement.