Quality objection processing: stainless steel plate is rusty

Case Overview

During the process of using stainless steel, the customer found that some products were rusty, so they raised a quality objection to the stainless steel plate supplies.

Case Study

After on-site inspection, this batch of steel plates has been bent into shape, made of 304/2B, and there are slight rust spots on the surface of the steel plates, which are distributed on the edges of the steel plates. Through laboratory tests, the content of chloride ions and oxygen atoms in the rust spots were abnormal.
Through process analysis, the following conclusions are basically drawn:

  1. Through on-site investigation by the customer, it was found that the steel plate was pushed by two workers by hand when the customer was in Kaiping, and the workers did not wear gloves.
  2. The rust spots contain a large amount of Cl element, and when Cl element exists on the surface of stainless steel, it is prone to corrosion.
  3. Human sweat contains about 0.2~0.3% NaCl, so after a period of time, after the stainless steel surface is contaminated by sweat, rust spots may appear.
  4. In summary, the possible reasons for the rust on the surface of the customer’s product are:
    During the blanking process of the customer in Kaiping, the hand of the worker touched the steel plate. In addition, the weather was very hot in summer and it was easy to sweat, so more sweat was left on the stainless steel plate.
    During the processing of the product, the sweat was not cleaned immediately. After a period of time, the sweat on the steel plate produced rust spots.
    On the other hand, the presence of sweat tends to absorb dust and other particles in the air, and it is easy to form corrosion batteries, leading to corrosion and rust.
Process Result

Customers are advised to wear gloves when processing stainless steel.
In fact, in general, in machining centers, operators wear rubber gloves. One can prevent sweat from contaminating the stainless steel surface, and the other can prevent hands from being scratched by the stainless steel plate.

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