What is the acceptance method for non-standard screws

Update:28-03-2019
Summary:

First of all, the non-standard screw is also the evolut […]

First of all, the non-standard screw is also the evolution of the national standard screw. It is also necessary to determine the specific testing items according to the national standard standard for surface defects of screws. Please refer to the corresponding national standards for details. If surface coating and plating affect the identification of surface defects, Give the pick before the inspection.
Secondly, according to the design drawings, the dimensions and materials of the non-standard screws should be inspected. This should pay attention to the inspection of the materials. The raw material manufacturers should provide the material certificate report. Second, high-end products must be SGS material certification, and sent to the relevant laboratory for material composition analysis to confirm whether the composition content meets the requirements of the drawing material.
   The function requires non-destructive inspection. If non-destructive inspection is performed on non-standard screws, if any part of the quenching crack, the bearing surface and the following wrinkles are found, and whether the coating meets the environmental requirements of RoSH.
   Then there is the destructive test, such as non-standard screw hardness grade to do the corresponding hardness impact test; internal hardness, mechanical properties, torque test, etc. This will damage the non-standard screw, but the screw factory with strong quality concept is this A test item must be done.

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