Size Effect of Micro-bending Spring-Back for C5210 Phosphor Bronze Sheet

Micro-bending tests were conducted by RG-2000 micro-computer control electronic universal testing machine. The influence of thickness, grain size, bending radius of C5210 phosphor bronze sheet on micro-bending spring-back was researched. Results show that the thickness, grain size, bending radius of C5210 phosphor bronze sheet had a significant effect on the spring-back and that showed an obvious size effect. The spring-back amount decreased as sheet thickness increased, and thickness affected the spring-back amount obviously. The spring-back amount decreased with increasing of grain size, when the grain size was larger than 40 μm, the amount of spring-back decreased slowly. The spring-back amount increased as the bending radius increased, and the trend of increase was more obvious when the thickness of sheet was smaller.