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  • 1.  Stainless Steel Discoloration

    Posted 11-06-2023 14:23

    Is there a reliable guide to temperature discoloration of 316 stainless steel in air? A general range of values for failure analysis of parts that have rubbed.



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    John Merrill
    Principal Engineer
    EagleBurgmann
    Matthews NC
    7048407045
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  • 2.  RE: Stainless Steel Discoloration

    Posted 11-07-2023 08:58
    The short answer is NO. Time at temperature is a big factor. There are charts for short times (a few hours). Surface conditions also have a major effect. (I’ve seen distinctly colored hand prints on heat tinted panels - probably due to salts. Organic contamination also has a great effect.)
    At least you’re asking only about one alloy. Differences in alloying content have a strong effect.

    -John Grubb - Sent from my iPhone


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  • 3.  RE: Stainless Steel Discoloration

    Posted 11-08-2023 09:12
    Abbott Furnace Company has a general color chart listing oxidation colors in steel in air, not specific to 316 SS however.
    Download Industrial Furnace Repair Troubleshooting Guides for sintering furnaces, brazing furnaces, steam treat furnaces and oxidation colors from Abbott Furnace Company
    abbottfurnace.com




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  • 4.  RE: Stainless Steel Discoloration

    Posted 11-08-2023 20:04

    The discoloration that appears on the metal surface is mainly result of oxidation. Oxidation will happen at certain temp at certain level of oxygen (see metal to metal oxide equilibria). These are the condition to start the oxide. 



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    Ytzhack Heber
    Metallurgist
    California Brazing
    Newark CA
    (510) 790-2300
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  • 5.  RE: Stainless Steel Discoloration

    Posted 11-07-2023 13:38

    I am not sure where I saw it, but I think it was an AWS source, or class on welding Stainless steels.



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    Patrick Mizik
    ASM Chapter Council Chair & District 11 Rep
    Owner
    Patrick Mizik Engineering, LLC
    pmizik.ks@outlook.com
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  • 6.  RE: Stainless Steel Discoloration

    Posted 11-08-2023 08:17

    The chart you are thinking of is AWS D18.2 "Guide to Weld Discoloration Levels on Inside of Austenitic Stainless Steel Tube".  It relates to the amount of oxygen in the purge gas and resultant heat tint after welding.



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    Peter Ditzel
    Principal Engineer, Materials and Processes
    Parker Hannifin Corporation
    Mentor OH
    (440) 266 2481
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  • 7.  RE: Stainless Steel Discoloration

    Posted 11-08-2023 12:03
    Edited by Jerrod Olivier 11-08-2023 12:04

    This does not apply to your question about 316, but API 579-1/ASME FFS-1, June 2016 has examples of carbon/low alloy steel color change due to exposure to elevated temperatures in Table 11.18(b), Figure 11B.2, and Figure 11B.6.


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    Jerrod Olivier
    Senior Consultant / Partner
    Precision Engineering Solutions, LLC
    New Iberia LA
    (337) 364-0080

    info@prec-engr.com
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