The materials of tension spring include musical instrument metal string and stainless steel wire
Instrument wire: the wire conforms to astm-a228 or AMS 5112. When the temperature is higher than 121 degrees Celsius (250 degrees Fahrenheit), it is not recommended to use the tension spring made of the wire
Stainless steel wire: type 302 of stainless steel conforms to astm-a313 or AMS 5688. The spring is tempered (only physical and chemical treatment). When the temperature is higher than 260 ℃ (500 Fahrenheit), it is not recommended to use the tension spring made of musical instrument string wire wire. The stainless steel model 302 is slightly magnetic. There will be a little residual nickel on the surface of stainless steel, which is a normal phenomenon, It will not affect the performance of the product
Other metal materials: hard drawn steel, Inconel, oil tempered steel wire, Monel, chromium vanadium steel, beryllium copper, chromium silicon steel, Elgiloy, phosphor bronze, galvanized piano steel wire, etc