氮化硅轴承球超低温承载特性试验研究

Load-bearing properties of silicon nitride bearing balls under ultra-low temperature

轴承球的超低温承载特性是其在超低温环境下应用和超低温轴承匹配设计的关键 .模拟轴承零件配副 ,采用两球对压检测其破碎载荷的方法研究了氮化硅 (Si3 N4 )球和 9Cr18钢球在液氮温度下承受静载荷的特性 .结果表明Si3 N4 球在超低温下破碎时的名义接触应力在 2 7～ 2 9GPa ,足够满足滚动轴承应用的需要 .并且同 9Cr18钢球一样 ,Si3 N4 球超低温下承载能力要高于常温承载能力 .以Si3 N4 球和 9Cr18钢球配对承载时 ,虽然Si3 N4 球无明显塑性变形而 9Cr18钢球有较大屈服 ,Si3 N4 球承载能力仍远大于 9Cr18钢球 ,在设计以Si3 N4 球和 9Cr18套圈组成的混合式陶瓷轴承时应考虑对套圈采用适当的表面强化处理 .

According to the mating materials of bearing elements, the static load-bearing properties of silicon nitride balls and 9Cr18 steel balls in liquid nitrogen are measured by ball-to-ball crushing testing. The results show that when the balls are tested under ultra-low temperature, the nominal contact stress of silicon nitride balls of 11.113 mm in diameter is between 27-29 GPa, and it is high enough to meet the demand of cryogenic bearing. The load-bearing capacities of both silicon nitride balls and 9Cr18 balls under ultra-low temperature are higher than under room temperature. When silicon nitride balls are pressed against the 9Cr18 ones, the silicon nitride balls have no plastic deformation. The 9Cr18 balls have great plastic deformation, and the load-bearing properties of silicon nitride balls are much higher than the 9Cr18 ones. So when designing the hybrid ceramic bearings with silicon nitride balls and 9Cr18 rings, the surface of the steel raceways should be properly modified.