Seamless steel pipe is a hollow tubular product made from round steel or billet through piercing, hot rolling, or cold drawing processes, with no longitudinal weld seam, offering better pressure-bearing capacity and structural consistency than welded pipes. It is primarily used in medium-to-high pressure or high-temperature applications such as petroleum, chemical, boiler, power station, hydraulic systems, and mechanical structures, with common materials including carbon steel, alloy steel, and others.