Or horny carbide. customized chipboard screws steel workpieces with surface decarburization are more likely to form network cracks after quenching. This is because the volume expansion of the surface decarburization layer during quenching and cooling is smaller than that of the undecarburized core, and the surface material is affected by the expansion of the core.
It was pulled apart into a mesh. The quenching cracks on the surface will cause the bolt to break suddenly, and the fracture source of this type of fracture is on the surface. 2. Torque overrun Torque alarm usually occurs in the bolt assembly process where the torque is controlled by the angle method. The failure modes and reasons that cause the fastener torque to exceed the limit are: (1) After the assembly is completed, the final torque of the part is higher than the upper control limit or lower than the lower control limit. The reason is that the assembly torque control range of the parts is unreasonable.
The performance is that the set control range is too small and the control range is shifted upward or downward. (2) The torque reaches the upper limit without preloading to the preset angle. The reason is that the friction coefficient of the part itself exceeds the upper limit, and the friction coefficient of the part matching exceeds the upper limit, and the interference between the parts causes the assembly torque to rise sharply. (3) Normal installation, lower torque limit alarm.
The reason is that the friction coefficient of the part itself exceeds the lower limit or the friction coefficient of the part matching exceeds the lower limit, and the fitting torque when the part is screwed is greater than the initial torque (that is, the screwing torque is too large), which is common in the tightening of the lock nut. 3. Hydrogen embrittlement Fasteners are prone to hydrogen embrittlement, and hydrogen embrittlement is the main cause of fastener fracture.
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