Boiler tube are widely used in power-generating, heating and ventilation industry. Boiler tubes are a part of tubing components of utility and industrial boilers.
Boiler tube in power-generation are used only for utility boilers to generate steam for electricity production. Utility boilers is the boilers with high pressure and high temperature, designed for pulverized coal, oil or natural gas — focusing on emission control more cost effectively than industrial boilers. Usually giant in size, produce 3 500 000lb of steam per hour, operate at a steady rate close to the maximum capacity, continuously to meet constant demand for steam (leading to lower operating costs when compared to industrial boilers). Boiler tubes are used in reheaters and superheaters of a power plant boiler. During the last years operating temperatures and pressures of boiler tubes are increasing up to 700°C and 300 bar and higher, thus leading to dominating role of supercritical and ultra-supercritical technologies of boiler tube production.
Boilers for industrial applications produce steam or hot water for process applications for various industries — biomass firing (fluidized bed boilers), heating, pulp and paper industry (recovery boilers), recovery boilers, various chemical processes. Boilers are used for different combustion systems (conventional coal, oil and gas). Small in size. Most industrial boilers range in size from 10,000 pounds of steam per hour to 1,200,000.
The most popular steel grades, that are used for boiler tubes production are 321H, 304H, 347H, 347HFG. Austenitic boiler tubes are used in boilers superheaters with high specified temperature and supercritical pressure.
There are two methods of boiler tubes manufacturing: cold finished and hot finished. Boiler tubes are mainly heavy-wall tubes (to sustain high pressure), of fixed length, the diameter range of Boiler tube is varying from 30.0 mm to 80.0 mm.