Phosphorous tin bronze is a famous elastic material. It is necessary to control the grain size before cold processing and low temperature annealing after processing. The strength, elastic modulus and fatigue strength of fine grain machined material are higher than that of coarse grain machined material, but the plasticity is lower. The annealing hardening effect can be produced when the cold processed material is annealed at a low temperature of 200~260℃ for 1~2h, which can further improve the strength, plasticity, elastic limit and elastic modulus of the product and increase its elastic stability. There are altogether 4 grades of phosphorous tin bronze included in China's national standard. Tin (Sn) x Qsn6.5-0.1 alloy is mainly used to make elastic elements, especially spring contact plates with good conductivity, wear-resistant parts and antimagnetic elements in instruments and meters. Qsn6.5-0.4 alloy is mainly used in papermaking, chemical industry and food industry manufacturing metal mesh, also used in the manufacture of wear-resistant and spring parts; Qsn7-0.2 alloy is used for friction bearing parts, such as bearings, bushings, turbines, etc., under medium load and sliding speed. It can also be used for making elastic components and other mechanical and electrical parts. Qsn4-0.3 alloy is used for the production of various pipe materials in pressure gauges, as a sensitive element, pressure gauge bronze. The significance of folded tin-phosphor bronze grade Why is the brand qsn6.5-0.1? Maybe many people would like to ask this question. In fact, it is named according to the content of tin-phosphorus bronze, such as Theoretical significance of qsn6.5-0.1: content of Sn (6.5%), zinc (Zn)+ other impurities (0.1%), copper (Cu) as margin The same qsn4-0.3 and qsn7-0.2 are also used in the same understanding to see the content of brand number, but in the actual smelting process, there will always be a certain error range, and each brand number will he a certain range standard according to the national standard: Brand number: qsn6.5-0.1 standard :GB/T 4423-1992 Chemical composition: copper Cu: margin, tin Sn :6.0~7.0, lead Pb:≤0.02, phosphorus P:0.10~0.25, aluminum Al:≤0.002, Iron Fe:≤0.05, silicon Si :≤0.002, antimony Sb :≤0.002, bismuth Bi:≤0.002 note :≤0.1(impurity) Brand number: qsn6.5-0.4 standard :GB/T 13808-1992 Chemical composition :Sn:6.0-7.0, Al:0.002, Zn:0.3, Fe:0.02, Pb:0.02, Ni:0.2, P:0.26-0.40, Cu: residual, impurity :0.1 Brand number: qsn7-0.2 standard :GB/T 2059-2000 Chemical composition: copper Cu: margin, tin Sn :6.0~8.0, lead Pb:≤0.02, phosphorus P:0.10~0.25, Aluminum Al:≤0.01, iron Fe:≤0.05, silicon Si :≤0.02, antimony Sb :≤0.002, bismuth Bi:≤0.002, note :≤0.15(impurity)