Global economic recovery. According to Zhihu's inquiry, the reason for the sharp rise of 1997 steel price is the global economic recovery. Iron and steel, that is, iron-carbon alloy, is a binary alloy composed of iron and carbon. The reason why iron and steel materials are widely used lies in the wide range of available components, from industrial pure iron containing almost no carbon to cast iron containing about 4% carbon, in which the phase structure and microstructure of the alloy have changed greatly.