Measure appearance and dimensions from a controlled drawing
Head diameter and height, shank diameter and length, layer thickness, concentricity, radius and surface condition are some of the basic controls. Measuring instrument, accuracy, reading location and sampling program should be known.
Creases, cracks, deep scratches, contamination, abnormal discoloration, and deformation can affect assembly or switching and must have clear acceptance criteria.
Match the alloy identity with the order requirement
The chemical composition should be compared with the ordered grade. In composite structures, the composite report alone does not indicate the location and distribution of phases or the quality of the layer bond.
The certificate of the alloy, the batch number and its connection with the delivered product make it possible to trace the test result.
Choose physical and mechanical properties purposefully
Density, hardness, tensile strength, elongation and specific resistance are some of the tests that can be used; But not all of them are necessary for every piece and every order.
The acceptance range should be extracted from the alloy specification, production method and final application, and the test method should be recorded along with the result.
See interphase and microstructure
Transverse and longitudinal sections can reveal layer continuity, porosity, cracks, alloy displacement and microstructure uniformity. Section direction and magnification should be recorded in the report.
The imaging result is comparable when the sample preparation and viewing area are the same each time.
Complete the lab result with system performance
Acceptance of alloy and dimensions alone does not guarantee the electrical life of the assembly. Contact resistance, temperature rise, weldability, erosion and number of cycles should be evaluated under representative conditions.
Determine the test criteria and conditions before starting so that the result can be used for production decision.
Practical summary
Any alloy, geometry, or corrective action decisions must be verified by controlled drawing and representative testing on the final assembly.
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