T8钢导柱(如图)淬火要求硬度为Rc58～61度。过去必须通过急冷才能达到此硬度。但用水急冷,变形严重,有时竟达0.3毫米。先水后油进行分级冷却,时间又掌握不准,水冷时间长了,易产生裂纹,短了硬度达不到要求。由于上述原因常出现废品。我们应用了优选法作了试验,就得到了最佳的分级冷却时间。 T8 steel guide column (pictured) quenching required hardness Rc58 ~ 61 degrees. In the past it had to be quenched to achieve this hardness. However, water quench, severe deformation, sometimes as much as 0.3 mm. After the first oil water graded cooling, the time is not allowed to grasp, water cooling for a long time, easy to produce cracks, short hardness does not meet the requirements. Due to the above reasons often appear scrap. We applied the best method of testing, we got the best classification cooling time.