1. It may be a hardware screw wire problem, that is to say, the quality of the screw wire is not good, there are more impurities, and the hardness is not enough. In this regard, you can replace the good screw wire, or you can harden the screw. Make the hardness within the specified index. After hardening, in order to prevent the screw hydrogen embrittlement.
You can ask the electroplating factory to remove hydrogen from the screw after hardening the screw and when you get it to the electroplating factory.
2. It may also be a technical problem in the production process.
The opposite side of the hexagon socket of the hexagon socket screw is too large. The reason is: the quality of the punch is not good, the dimensions of the three sides are not the same, the hexagonal edges are not clear, the taper is too large, the upper limit of the R angle reduces the limited depth, the punching pin taper is wrong, and the taper length is small and large.
When forming a two-stroke forming, the opposite side of the upper part of the inner hexagon is bigger. The lubricating oil is too thick and the exhaust is improper, causing the inner hexagon to hold its breath when forming, and the opposite side of the hexagon is too big.
