I have a stainless steel question.

[pwade]

I have a stainless steel question. Some small table top gas and charcoal grills are made from stainless steel. I believe they are made from 409 stainless. After use they turn a golden color from the heat.
My question is at approximatly what temperature does the color change occur?

Thank,
Paul

 

[metman]

I will guess at about 425 deg F

Design for RELIABILITY, manufacturability, and maintainability

 

[Metaljon]

Have a read of this article.

http://www.asfabrications.co.uk/technical/steel-information/tempering-colour-chart/

The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change. However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases and classification of stainless steel. The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colours is delayed.

The golden yellow colouration occurs at 230 to 240 deg C or 446 to 465 deg F.

 

[pwade]

Thanks for the info. As a test I ran a couple of pieces through our powder paint oven. It is set at 400 deg F. two small areas near holes colored a little. Now I think I was slightly below the temperature needed for a color change.

Thanks again

 

[EdStainless]

With repeated exposure this color will get darker and duller.
These tinted surface are also much more prone to rusting, so be careful if they are for outdoor use.

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Plymouth Tube

 

[mrfailure]

Coloration occurs on heating from the formation of a thin oxide film on the surface, and is a function of film thickness. Film thickness in turn is mostly a function of temperature. After a short time the film will passivate and not usually grow thicker; thus maximum temperature of exposure can be estimated provided a minimum exposure time to passivate the film.

Aaron Tanzer

http://www.lehightesting.com