At present, the guide screw is quenched by medium frequency induction. In production, axial or network cracks often appear on the arc surface of thread raceway after grinding thread with quenched (tempered) screw rod.

即使在导轨丝杆的过程中，也只有肉眼才能发现裂纹，导致导轨丝杆报废。这不仅给企业造成了直接的经济损失，而且由于各种因素的影响，给企业生产带来了更大的压力。

Even in the process of the guide screw, only the naked eye can find cracks, leading to the scrap of the guide screw. This not only causes direct economic losses to enterprises, but also brings greater pressure to enterprise production due to various factors.

1.导轨丝杆原料不好

1. The material of guide screw is not good

主要原因是ccr15材料网状碳化物的退火组织不合格（含片状珠光体）。通过对裂纹盘条中碳化物的不均匀性和显微组织的分析，发现网状碳化或球化退火组织不良的盘条不合格，约占总数的40%。

The main reason is that the annealed microstructure of network carbide in ccr15 material is unqualified (containing flake pearlite). Through the analysis of the inhomogeneity and microstructure of carbide in cracked wire rod, it is found that the wire rod with poor network carbonization or spheroidizing annealing structure is unqualified, accounting for about 40% of the total.

碳化物的不均匀性导致感应淬火后表面硬度和内应力分布不均，内应力也集中在碳化物集中的部位。螺杆磨削时，由于各零件的内应力大于材料的屈服强度，会产生磨削裂纹。

The inhomogeneity of carbides leads to the uneven distribution of surface hardness and internal stress after induction hardening, and the internal stress is also concentrated in the carbides concentrated position. When the screw is ground, because the internal stress of each part is greater than the yield strength of the material, grinding cracks will occur.

导轨丝杆状珠光体的存在导致感应淬火后螺杆表面晶粒粗大，降低了钢的屈服强度。螺杆抛光时，在内应力超过材料屈服强度的部位会产生磨削裂纹。

The existence of rod-shaped pearlite in guide wire leads to the coarsening of the surface grains of the screw after induction hardening, which reduces the yield strength of the steel. When the screw is polished, grinding cracks will appear at the position where the internal stress exceeds the yield strength of the material.

2.精密导轨丝杆螺杆中频淬火热处理不良

2. Poor intermediate frequency quenching heat treatment of precision guide screw

主要表现为淬火温度高或回火不足。通过分析统计，丝杠磨削裂纹约占丝杠磨削裂纹总数的20%-30%。

It is mainly characterized by high quenching temperature or insufficient tempering. Through analysis and statistics, the grinding cracks of lead screw account for about 20% - 30% of the total number of grinding cracks.