The Types Of Screw Surface Defects
When using screws, we sometimes see the appearance of some screws are not very good, and some will have cracks. What kind of surface defects do the screws have? Screw surface defects : Crack Cracks are usually caused by excessive stress during forging or other molding processes or heat treatment. Among them are: quenched cracks, forged cracks, forged bursts, shear bursts. Quenching cracks During the heat treatment, quench cracks may occur due to excessive thermal stress and strain. Quenching cracks are usually irregularly intersecting and appear in the direction of fasteners in an irregular direction. Forging cracks Forging cracks may occur during the blanking or forging process and are located on the top of the head of the screw, as well as the raised portion of the pocket head. Forging Burst Forging bursts may occur during forging. Shear burst Shear bursts may occur during forging. If it appears on the circumference of the round head or flange surface of...