Rainbow effect

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Hello everyone!Guys, what do you usually call the effect in the picture below?Any formal term for that in the U.S.? Attached ImagesLast edited by Jack8rkin; 05-14-2012 at 03:23 AM.
Reply:The rainbow you are speaking of is what we call Heat Affected Zone. Or at least thats what we call it in the south.Magicial Magician Of Molten Metal2006 Chevy Dually Welding Truck1975 SA-200 Lincoln Red SealMiller AEAD 200-LELincoln 225 AC/DC tombstoneVictor Contractors Flaming TomahawkProfax Tig RigMore pipe fitting tools to mentionMetabo's
Reply:Thank you.How do you describe the color? I understand the coulour may speak about the tempreature of welding.Overburnt parts will be blue. Right?Could I call it heat-affected zone color?Any other ideas?
Reply:Yes the colour of the oxidation does indicate colour.ColorTemperature                 Deg F              Deg CPale yellow 428                  220Straw         446                  230Golden yellow 469                  243Brown          491                  255Brown dappled with purple  509                  265Purple 531                  277Dark blue  550                  288Bright blue  567                  297Pale blue  610                  321This will give you the idea..  The list above is from this sitehttp://www.primitiveways.com/Steel%2...treatment.html
Reply:Thank you.
Reply:The "rainbow" of colours are what a blacksmith uses to temper carbon steel.  Hi carbon steel would be heated to red hot then quenched in water.  Then the steel is polished and reheated until the desired colour shows then the steel is requenched to stop the process.  This is how chisels were hardened and springs got their temper so they could bend without breaking yet hold their shape.  Lotechman's chart seems to be reasonable as to the temperatures the colours represent."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Thank you. But could we get back to welding?Could I call the color of the heat affected zone the "oxidation color"?Or is it the "color of the heat affected zone"?Maybe you use something else as a term for that in the U.S.?I'm speaking precisely about welding. Not about tempering,Some colors may speak about the excessive oxidation of the near-weld surface. These overoxidized portions of the surface have to be removed. This is why I'm asking about the term that describes the "rainbow" and goes before the word "color", like "rainbow color". But It's not "rainbow" as I see from the above responses.Last edited by Jack8rkin; 05-14-2012 at 01:59 PM.
Reply:The colors are formed from oxidation of the base metal with the oxygen in the air as the metal is heated.Different terms to describe it could be "temper colors" or "heat tint" or "interference colors".  The best laid schemes ... Gang oft agley ...
Reply:This has something to do with heat and metal.  It's called  "case hardening," which is beautiful on guns.  The heat affects the colors in the metal.  Unless I'm wrong, I believe that "Case Hardening" however is created at lower temps than true "arc" type welding methods. Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
Reply:Originally Posted by SuperArcThis has something to do with heat and metal.  It's called  "case hardening," which is beautiful on guns.  The heat affects the colors in the metal.  Unless I'm wrong, I believe that "Case Hardening" however is created at lower temps than true "arc" type welding methods.
Reply:Originally Posted by MoonRiseNope.Although "color case hardening" can give all sorts of "heat tint colors", that is a specific process whereby extra carbon is infused into the surface of the lower carbon content base steel in order to end up with a surface layer of much higher carbon content steel (aka a 'skin' of high-carbon steel on top of the lower-carbon base material).You may end up with the heat tint colors when doing color case-hardening (that is one of the generally desired results there), it is a semi by-product of the process when heating the steel and getting some partial surface oxidation of the hot steel.What is causing the various rainbow colors is the heat-induced partial oxidation of the metal. How and why the heating occured is not the 'why' of the colors.  So, heating with a torch to preheat the metal, or heating the metal to heat treat it, or heating the metal because you welded it all are the how and why of the heat.  And then the hot metal reacts with the oxygen in the air and you can get various "heat tint colors".