Letter 24099

Red rust on 316 Stainless steel BBQ stands

+++

Hello,
I recently designed a BBQ stand. I got a chap to manufacture it for me here in Hong Kong & asked him for 316 SS. I was going to be putting this thing outdoors in a very humid environment.
The stand is finished & looks great.

Two weeks after completion & usage I was cleaning the BBQ & saw RUST (Brown RUST?) I was researching 316 SS & I thought it corroded , but RUSTED?

Please could anyone help me in doing a home test to see if this chap has ripped me off! I put a magnet next to it & it is SLIGHTLY magnetic, but only slightly...This seems strange.

Thanks for your time.

Richard Clausen
pilot - Hong Kong, SAR, Hong Kong

Firstly, rusting is corrosion. It is the oxidation of one of the metals (iron) in stainless steel. Secondly, virtually all stainless steels will corrode under the correct conditions and one of the best ways of doing it is to heat it up to high temperatures and let it react with a damp atmosphere. Thirdly, 300 series stainless steels are slightly magnetic and will become more so when they have been cold worked, like when the BBQ was fabricated. I very much doubt you have been ripped off as the stainless steel is behaving exactly as I would expect it to! Just out of interest, why did you specify 316 stainless steel? It is one of the most common grades of stainless and is regarded as a workhorse in the stainless world, but its corrosion resistance at elevated temperatures is not great. Remember, when it is used in cooking utensils, the steel will only reach temperatures of a few hundred degrees Celsius as ovens don't go much higher and when boiling water, it will be limited to little more than 100C. These are not the conditions found in the fabric of a full blown BBQ.

Trevor Crichton R&D practical scientist - UK