变质试验保持架是滚动轴承的四大零件之一,在使用过程中要承受较大的冲击负荷,并在高速下运转,设计要求:σ_b≥18kgf/cm~2,δ>5％,硬度HB50～80。由于ZL102共晶铝硅合金具有优良的铸造性能,良好的耐蚀、耐热性能,较好的耐磨性及比重小,线膨胀系数低的特点,因此是常用的一种压铸合金。它可以通过变质处理达到我们所要求的机械性能。1.变质方法的选择对铝硅合金的变质处理,通常是用Na或Na盐变质,但用Na变质的有效期在40～50分钟左右,效果保持时间很短。此后为达到变质效果还要再次加入 Metamorphic test cage is one of the four parts of the rolling bearing, in the course of the process to bear a greater impact load, and run at high speed, the design requirements: σ_b ≥ 18kgf / cm ~ 2, δ> 5%, hardness HB50 ~ 80. As the ZL102 eutectic Al-Si alloy with excellent casting performance, good corrosion resistance, heat resistance, good wear resistance and small proportion, low coefficient of linear expansion, it is a commonly used die-casting alloys. It can be metamorphic to achieve the mechanical properties we require. 1. The choice of metamorphism Al-Si alloy modification, usually with Na or Na salt deterioration, but with the deterioration of Na is valid for about 40 to 50 minutes, the effect of holding time is very short. Since then metamorphic effect to be re-joined