Electroplating Of China Stud Supplier

    1. Thickness of plating layer of Hexagon Socket Head Bolt
      In the electroplating process of threaded fasteners, whether barrel plating or rack plating is used, the thickness of the plating layer obtained by each fastener in a batch of products is different, that is, the plating layer distribution on the same fastener is also uneven. of. For example, the coating thickness of the thread crest is thicker than the pitch diameter and the bottom of the tooth, and the coating thickness of the two ends of the screw and bolt is thicker than the middle, and it becomes more significant as the length to diameter ratio increases. The same is true for nuts.Due to the shielding effect of the nut electroplating process, the thickness of the electroplating layer on the internal thread is very thin.Only the first buckle at both ends is thicker than the middle part, which is equivalent to the hex wrench surface thickness.
        2, how to describe the plating thickness of a batch of threaded fasteners
        In view of the uneven distribution of the plating thickness of threaded fasteners, the standard quoted four definitions of plating thickness, namely "nominal plating thickness", "batch average thickness", "local thickness" and "effective plating thickness". "Nominal plating thickness" refers to the nominal plating thickness of threaded fasteners and cannot represent the actual plating thickness. The actual plating thickness of threaded fasteners is described by "effective plating thickness". "Effective coating thickness" includes two aspects of "batch average thickness" and "local thickness".
      The plating thickness of threaded fasteners cannot be represented by the plating thickness of a part. Regardless of the threaded fasteners processed by rack plating or barrel plating process, each part in the same batch of parts cannot reach the same plating thickness, but the thickness The change obeys the normal distribution. We assume that the thickness of the coating is evenly distributed on the surface of the batch of parts to calculate the average thickness of the coating. This leads to the concept of "batch average thickness", which can be used to describe the entire batch. The coating thickness of the batch of threaded fasteners. The "batch average thickness" in standard table 1 is a range. The minimum batch average thickness is to ensure the anti-corrosion requirements of the threaded fasteners, and the maximum batch average thickness is to ensure the screwability of the threaded fasteners after plating.

    China Stud Supplier's "local thickness" in the standard actually refers to the minimum local thickness, and the minimum local thickness describes the minimum specified value of the coating thickness that the threaded fastener should reach on the specified local test surface. The data verified by the test shows that the local coating thickness values ​​measured on the specified local test surfaces of screws, bolt heads and screw, bolts, and nuts are all greater than the average thickness of the batch, which is usually the average thickness of the batch. The value meets the requirements, and the minimum local thickness can also meet the requirements. The test results also confirmed that the numerical relationship of "nominal coating thickness", "batch average thickness" and "local thickness" is correct, which constitutes the theoretical basis for the detection and acceptance of the plating thickness of threaded fasteners.