Article Source: http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3778832 Weima Wall-Hung Boiler Repair Discussion: Characteristics of High-Pressure Valves. High-pressure valves must withstand very high pressure and temperature. Their characteristic is the absence of flanges, as they are directly welded onto pipelines and equipment, which greatly reduces the chance of leakage but also creates certain difficulties for valve maintenance work. The materials used in high-pressure valves are the same as those used in boiler pressure-bearing components; valves used in steam pipelines and steam systems are made of heat-resistant alloy steel, while valves used in feedwater pipelines and water-cooled wall systems are made of high-quality carbon steel.