The cause of rust between processes caused by pre-coating treatment.

The problem of rust return between the pre-coating process of work parts has become the most important concern of our customers. After the work piece is rusted, it directly affects the quality of the pre-treatment film, which in turn affects the coating effect. Therefore, how to do a good job of rust prevention between processes is one of the key work of pre-coating treatment

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(with acid washing process) phosphorus-free pre-treatment process typical process flow:
pre-skimming - main degreasing - washing 1 - (acid washing) - washing 2 - (washing 3) - silane / terracotta treatment - washing 4 - washing 5 - leaching - electrophoresis / spray powder / paint
The reasons for the rusting between processes are mainly as follows:
1, the main degreasing after washing 1 overflow water too large
cause analysis: work parts before entering the silane / pottery tank, if the overflow water is too large, may lead to slot pH weak acidity, resulting in workware rust.
measures: adjust the flow rate of overflowing water appropriately, control the pH of the tank fluid, and add rust inhibitor appropriately.
2, there is acid washing process of the pre-treatment process, washing 2 is not sufficient
cause analysis: the work piece before entering the silane / pottery tank, if the washing 2 is not sufficient, the acid left on the surface of the work piece will cause the work piece rust.
: Add rust inhibitors appropriately.
, workshop temperature is too high
cause analysis: summer workshop temperature is too high, will cause the water temperature of the sink to rise, more than 35 degrees C, the surface of the work piece will appear rust.
Responsive measures: keep the workshop ventilated and dry, the temperature remains within 35 degrees C
, appropriately increase the flow rate of water spillage in the sink, reduce the water temperature, appropriately add rust inhibitor

: Add rust inhibitors appropriately.
, draining time is too long
cause analysis: long draining time leads to long-term exposure to wet air, resulting in work parts rust.
Response measures: increase the blow-drying device in the drainage area, or reduce the length of time the work parts stay in the drainage area, add a small amount of rust inhibitor
6, emergency stop line
cause analysis: emergency stop line, the work parts exposed to the air for a long time, resulting in rust.
: The surface rust of the work piece is manually polished and reprocessed when production resumes.
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