Letter 37062

SS 431 corrosion resistance  

+++++

What are the steps to follow to get atleast 200 hrs of No corrosion in a Salt Spay test ( BS EN 248 ) done on a SS431 matl rods used as a plunger in water solenoid valves.

1) Do we need to heat treat, temper, centerless ground and electro polish.

Please advise.

Thanking You and Best Regards,

RAGHU
INOVA INDIA - TN, INDIA

Heat treat and temper have to do with hardness. Centerless grinding is a choice of finishing methods. Electro polish can go a long way to improving the salt spray test results. 431 does have 1.25 to 2.5 % nickel, so it has a chance at passing a 200 hour test, but I have doubts. After EP, it is only going to take one fingerprint or being touched by a steel tool, such as a micrometer to have it fail.
I certainly could be wrong. You will have to make the parts and test them to see if it will pass on a repeated basis.

James Watts
- Navarre, Florida

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