（北京華立精細化工公司 北京昌平 102200）
How to Place Your Workpiece during oil Quenching
（Beijing Huali Fine Chemical Co. , Beijing 102200, China）
Abstract: The oil quenching process of different workpieces placed in straight way and other various inclined ways were videoed. This study compared the cooling rate and evenness of the workpieces under different placement ways. The results show that compared with straight sample, inclined sample can be cooled down faster and evenly. During the cooling process, an upside-down heap of gas is observed at the downwards-facing horizontal surface. The existence of the upside-down heap of gas greatly decreased the cooling rate of the downwards-facing horizontal surface, thus led to a great difference in temperature between different areas of the workpiece. This study also presumed the formation mechanism and evolution process of the upside-down heap of gas, and a method for preventing the emergence of it is put forward. The flowing rule of gas inside the vapor blanket and the middle stage properties are the reasons for the above mentioned phenomena and differences. The cooling effect of all above tests revealed two characteristics: (1) significant relative differences in thickness occurred between different parts of a workpiece; and (2) symmetrically shaped workpiece can not receive corresponding symmetrical cooling effect.
Keywords: : quenching， liquid quenchant， fine quenching technique，computer simulation