A precision alloy with abnormal thermal expansion characteristics, also known as controlled expansion alloy, is widely used in the fields of electronics industry, precision measuring tools, precision instruments and low temperature engineering. In addition to a specific thermal expansion coefficient, the expansion alloy also requires good sealing, weldability, corrosion resistance, machinability and ease of machinability according to different uses, and it is not allowed to cause expansion within the operating temperature range. A distinct phase transition. The chemical composition of the expanded alloy must be accurately controlled during the manufacturing process, and its products are generally rods, plates, strips, wires and pipes.