Plastic steel doors and windows were developed in the late 1950s by West Germany and began production in 1959. The original plastic-steel doors and windows were all simple and rough. With the worldwide energy crisis in 1972, the plastic steel doors and windows with better energy-saving effects in the early 1970s were used extensively, which also promoted the improvement of profile production technology. The performance is improving day by day, from the original single-cavity profile to three-cavity and four-cavity profiles, which also promoted the development of steel doors and windows in Europe and Asia. According to incomplete statistics, the use of plastic steel doors and windows in Germany has accounted for 52% of the door and window market, Austria is 48%, Switzerland, Britain, France, Italy and other developed countries also have 10-20%; American steel doors and windows in the late seventies Starting from the beginning, the annual growth rate of usage is over 15%. At present, Japan uses plastic steel doors and windows in Japan, Korea, Taiwan, Singapore, and Thailand.