在建造船舶以及其它产品中,经常要加工一些形状复杂的曲面,共中,单向曲面可以用冷工加工,双向曲面则必须用火工加工。以前,用火工加工时,先把钢板在炉灶内烧红,然后取出,由人工用大锤敲成一定的形状(只有批量很大的才做模子在水压机上压出),劳动强度很大,生产率也很低(从平的钢板加工成曲面往往要烧几次,敲几百下大锤)。 In the construction of ships and other products, often to process some complex shape of the surface, a total of one-way surface can be used cold work, two-way surface must be used to deal with the fire. In the past, when working with a fireman, the steel plate was burned red in a stove and then removed, and then manually shaped into a shape by a sledgehammer (only a large number of molds were pressed on a hydraulic press). The labor intensity was large , Productivity is also very low (often flat to the surface from flat steel to burn several times, knocking hundreds of sledgehammer).