Quality Inspection Method for Zhuji Spring Phosphating
2023-04-26
To extend the lifespan of springs, Zhuji spring manufacturers will perform a phosphating treatment on the surface of the finished metal springs. The quality of the surface phosphating treatment affects the quality of the product. How can users conduct quality inspection?
I: Immersion Method
Place the phosphated spring into a 3% sodium chloride solution, set the liquid temperature to 15～25℃, and observe after soaking for 2 hours. If there are no obvious signs of rust, the surface treatment process of the product is relatively good.
Alternatively, in a 5% copper sulfate solution, after soaking for 2 minutes, a yellow substance appears on the surface, which is a compound formed after metal oxidation. This indicates that the phosphating treatment of the spring surface is poor.
II: Dropping Method
Mix copper sulfate and sodium chloride in a 2:1 ratio, evenly mix, and use a tool to drop the solution onto the surface of the spring. After waiting for 5 to 10 minutes, observe whether there is obvious rust on the surface of the spring. If the dropped area is the same as other areas, the quality is better.
Another drop test method is to mix copper sulfate, sodium chloride, and hydrochloric acid in a 2:1:10 ratio and observe after dropping for three minutes whether there is any yellowing on the phosphating surface.
III: Scraping Method
The surface firmness of springs treated with phosphating is relatively good. A thin pin can be used to gently scrape the surface. If obvious scratches appear quickly on the surface, the treatment process is relatively poor.
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