为减少一些较长刀杆的淬火变形,过去只是在冷却方面想办法,虽能减少变形,但仍不够理想。以图1镗刀杆为例,因该刀杆除键槽外还有七个通孔,孔壁又薄,在热校直时最容易在孔处压断。后来,只好不进行热校直,但给回火后校直带来很大困难,劳动强度大,校直效率低。最近,我们处理一批45Cr刀杆,根据这种材料和形状(一面有键槽)以及在硝盐中冷却的变形规律(带键槽一侧四进,见 In order to reduce the quenching deformation of some longer arbor, in the past only think of ways to reduce the deformation, but it is still not ideal. Take the boring bar as an example in FIG. 1, because the boring bar has seven through holes in addition to the key slot, the wall of the hole is thin, and the hole is most likely to be crushed in the thermal straightening. Later, had no heat straightening, but after the tempering straighten bring great difficulties, labor-intensive, straightening efficiency is low. Recently, we deal with a group of 45Cr arbor, according to this material and shape (with keyway on one side) and the deformation of cooling in the nitrate salt (keyway side four, see