Die springs are widely used in stamping die, metal casting, mold, and other elastic precision machinery, auto and other fields. Die spring materials generally used chrome alloy steel. Chrome alloy spring steel has the characteristic of high temperature resistance, rigidity and long service life. Rectangle die Springs is of small size, good elasticity, high rigidity, high precision, making material has a rectangular shape, surface color coating (plating) to compare different weight, appearance and so on.