Metal finishing Q&As since 1989

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Yellowing of stainless steel (304 grade)

We are manufacturing portable oven which has the stainless steel (304 grade) exterior. During baking of chicken (1 hr and 15 min) the exposed stainless steel becomes yellow. Which doesn't go even after cleaning.

Please advise on how to avoid this problem

Narayanasamy
- Pondicherry, Pondicherry, India
2003

Dear Mr Narayanasamy,

Please send at least two whole baked chickens to us for proper evaluation. Whilst you're at it, please also bake two legs of lamb (preferably with pepper and garlic seasoning) and observe if the yellow colour also comes whilst baking lamb. On receipt of the baked samples, we shall suggest remedial action.

Thanking you in anticipation of your immediate action,

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

2003

Mr Narayanaswamy,

I am sure the feeding of the poor will get you points. However please passivate your 304 in a proprietary SS passivate available in Chennai. It will help in keeping the SS from yellowing. The same gentleman that you sent all the lamb and chicken to has the right idea of sourcing such materials.

Regards,

Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
2003

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You don't say how hot the oven becomes, so it could be that you are beginning to oxidise the stainless steel. It may be possible to reduce the cooking temperature, but be careful you don't start giving people food poisoning! Alternatively, you may wish to try electropolishing the stainless steel as this can sometimes stop unwanted staining

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2003