And if you’re a wizard, you’re probably casting spells instead of welding. So if your weld does not look as pretty as the one above don’t worry. The higher the heat input the slower the cooling rate. Again, it depends somewhat on the industry and use, but typically you'd like the weld and HAZ to come out a bright silver/chrome color. For instance, take a look at the weld below: This is a beautiful GTAW weld. Same thing with inert gas: You want just enough flow to protect the heated metal from the atmosphere relative to the standards you’re welding to. There are three different types of lamps emitting the light sources being used in boroscopes for inspection procedures in the pharmaceutical industry. As the surface of the heated steel meets the atmosphere, it reacts with the elements in the air and oxidizes. (Unless of course you are talking about one of MY TIG welds… The goal is a nice golden straw colour but if it leaches into purple or blue your ok in most cases. Although austenitic stainless steel is readily welded, weld metal and HAZ cracking can occur. These are UHP, which will emit a blue hue, tungsten, which will emit a yellow hue, and metal-halide, which will emit a blue/green … Is an Amazon-like metal fabricator possible? 2135 Point Blvd., Elgin, IL 60123 (815) 399-8700. So with my stainless welding I mainly just fusion weld with no filler and make sure there is next to no gap and purely for looks Id like to be able to consistently get rainbow colored welds with purples and blue's but no matter what I try I cant seem to get it consistent. You may have heard that the yellow and straw colors are OK, but blue and purple may not be. The colors follow a predictable pattern, from chrome to straw to gold to blue to purple. TIG is like performing surgery, very precise and pays well. So, I’ll just give the rest of you a quick and dirty version. Discoloration is oxidation. This is due to chromium depletion in both the oxide and underlying alloy substrate. But the less color in titanium, the less chance that it is contaminated or compromised. A rainbow of colors in the bead and heat-affected zone (HAZ) doesn’t automatically make it a good weld, and it can indicate a bad weld. Austenitic Types 309 and 312 may be used for dissimilar joints. There was an error submitting your subscription. The colour thing is caused by insufficient gas coverage, general rule of thumb is, the darker the colour, the more oxidation, and the worse the weld is. Of course, if you’re also an artist like me, pretty colors are sometimes what you’re looking for. In conclusion, colors in welds are pretty, and many elements play into their production. Could steel prices soon hit $1,000/ton in the new year? On stainless steel, for example, any color in the weld or HAZ shows that an oxide layer has formed, which can affect corrosion resistance. I am disclosing this in accordance with the Federal Trade Commission’s. Are these colors acceptable? Fabricators & Manufacturers Association, Intl. 1/16th tungsten will weld 1/8" stainless just fine. Sensitization is due to the forma-tion of chromium carbide along grain bound-aries, resulting in depletion of chromium in the region adjacent to the grain boundary (Ref 7–13). But it’s just one of many factors. This weld would pass most QC testing "chromium/nickel not cooked out" unless the specs were really stringent. Weld Discoloration. The end. "Some swear there is a secret to it, others say its impossible. Please try again. The resulting heat input was 10.6 KJ/in which is relatively low. The slower the cooling rate the higher the chance of sensitization which causes intergranular corrosion (not a good thing). Is the tinting an indication of quality? The caveat here is also similar to stainless: it looks amazing when allowed to react. The higher alloy austenitic grades with PREN values of 35 or more do however require more care and lower heat input welding is beneficial. And that’s the big deal with using stainless steel, right? There is more to the weld than what it looks like from the outside. Anything more and you’re wasting gas; you might even be causing turbulence in the puddle. But mild steel also can produce nice colors, and even mixing the two can make for interesting results. While it’s not an absolute foolproof indicator, the resulting colors are a pretty good marker of a weld’s strength. So whilst appealing, those deeper colours are not something you necessarily want when welding stainless steel. The cool thing about t… Sometimes they indicate a bad weld, sometimes they don’t. There is a lot of science involved and maybe some magic. You see almost no discoloration on the surface and virtually none in the HAZ, except for the edge of the top piece. This is producing a false expectation and the impression that this tinting is good. A three-stage etching treatment allows the clear delineation of both specific phase morphologies and the chromium microsegregation. https://monkeyfabgarage.com/collections/welding-supplies/products/gls-fab-16-cup Coupled with the very low thermal diffusivity of stainless steel you end up with a vast array of colors (levels of surface oxidation). For instance, remember when you were a kid and you wanted to put 110 octane race fuel in your mom’s minivan (at least it smelled amazing)? If you were to use a really large tig nozzle, things would improve. But I can't say I've ever seen a stainless weld that had no color on the OD, but then again, I've never seen stainless done with a trailer. Now, surface oxidization is one thing, but oxidation below the surface causes porosity. The whole plant, flowers, stems and all, is dried and sold in bundles, and for dyeing and color-making it is broken up and stewed in water or a weak solution of alum. It corrodes prematurely. Their absence can be a good thing. The darker the color is, the thicker the oxidization. Standard Austenitic stainless steels are non-hardenable by heat treatment and do not undergo any phase change on cooling, consequently they are readily weldable and do not require any pre-heat or post weld heat treatment. But we call it ‘rainbow colors’ which makes it seem desirable. It all depends on the material, the industry, and the application. Gold is the darkest colour accepted by most of our codes. Once the procedure is qualified, follow it and don’t deviate. Color Met. It is important to develop a welding procedure that produces the quality from a structural standpoint as well as quality in terms of corrosion resistance. And lastly, it is affected by contamination from the atmosphere (even with 100% inert gas) and surface contaminants.. Ive tried going faster, slower. All of them indicate a change in color on the top layer of stainless steel – around the weld bead and within the HAZ (heat-affected zone). Regardless, we only recommend products or services we use personally and believe will add value to our readers. Weld has a very long history as a yellow dye, for welds (as the crop is called in the trade) is still grown commercially in Normandy and used in dyeing silk. First things first: Why does steel change color? Corrosion resistance. More won’t help. No synthetic dye has been able to replace it in this function. Disclosure of Material Connection: Some of the links in the post above are “affiliate links.” This means if you click on the link and purchase the item, we will receive an affiliate commission. In reality, that’s not the case. The gas flow needed could be different for every job, but as long as you’re getting just enough to cover the weld and HAZ until it’s below the contamination temp, you’re good to go. Please note: I reserve the right to delete comments that are offensive or off-topic. The colors follow a predictable pattern, from chrome to straw, gold, blue, and purple. More gas, better puddle control. Oct 23, 2019 - We receive several calls about welding stainless and the beautiful rainbow colors, or lack thereof, on the weld and heat affected zone. Are these colors acceptable? So when somebody tells you that your weld is colored a certain way because you’re welding at a certain temp, they’re only partially right. © 2021 FMA Communications, Inc. All rights reserved. Corrosion puts the integrity of the weld in jeopardy. More than likely the quality is excellent. Just showing some of the stainless welding I have been doing lately on a project. Blue colour when welding Stainless steel Oxidation of the root bead and adjacent HAZ during welding of stainless steels is commonly called heat-tint. We won't send you spam. When steel heats up, its structure changes. Thus the importance of qualification. Our product range includes machines for everyday heavy-duty work and occasional light weld cleaning, so you’ll definitely find the right solution for your application. In some industries, like pharmaceuticals, any color beyond chrome in the weld is unacceptable, but in other sanitary welding situations, such as dairy, up through light blues are allowed. A lot of hot rod and motorcycle guys will take their chances with material integrity on exposed piping and exhausts because it looks so dang cool when it turns blue and purple. In some industries, like pharmaceuticals, any color beyond chrome in the weld is unacceptable, but in other sanitary welding … What’s happening is the metal is oxidizing. Any color can be obtained but only the surface color is changed – the base metal is inherently silver. On stainless steel, for example, any color in the weld or HAZ shows that an oxide layer has formed, which can affect corrosion resistance. Corrosion resistance is reduced by oxidation. Yes, gas coverage can have an effect on a weld’s color. If you are one of the thousands that base their quality standards on Instagram posts please stop right now. The color depends on the temperature experienced by the weld and HAZ. If the gas coverage is left on the finished welding area as it cools, this area will remain silver or colorless. The questions are endless. And as the surface of the heated steel meets the atmosphere, it interacts with the elements in … This tint is nothing more than oxidation. "How do you get that perfect stainless weld? It is also affected by the heat input which determines cooling rates. 2 illustrates the directionally oriented austenite (white) and ferrite (blue) phases that exist in the unaffected base metal. That's why it's best to … Easily access valuable industry resources now with full access to the digital edition of The Fabricator en Español. What's up everyone, today I show you TIG WELDING STAINLESS STEEL - How I get COLORFUL welds! Your email address will not be published. A similar HI value on stainless steel that is 1/8 in. (It needs a minimum of 10% chromium to create this effect.) Unsubscribe at any time. But instead of just compromising corrosion resistance, the contamination from the atmosphere can actually affect the integrity of the weld—drastically. This creates an oxide “skin” that stops the iron from bonding with oxygen to create rust. The questions are endless. Your email address will not be published. For example, if you weld with 35 kJ/in. That is why gas welding steel with an oxyfuel torch looks so gray all over. Below that, you might get pinging, but using anything rated higher than what the engine was designed to run on isn’t going to help; it’s a waste. Those colors … Now check your email to confirm your subscription. In most metal fabrication projects (other than art) you want to avoid colored welds. The darker the color, the thicker the oxidization. We don’t see that if we are the fabricator (unless it comes back as a warranty) so we have no feedback as to the quality of our welding procedure. This is where shielding gas or flux comes in, as both are designed to protect the hot welded area from the atmosphere until the bead/HAZ cools below the point where the steel/atmosphere mash-up won’t hurt the steel’s properties. And if you’re a wizard, you’re probably casting spells instead of welding. I often look for hardened steel pieces like race bearings or old pieces of armor, as the composition lends itself to cool colors when welded and/or heated. Colour Formed Approx Temperature C pale yellow 290 straw yellow 340 dark yellow 370 brown 390 purple brown 420 dark purple 450 blue 540 dark blue 600 Why do they need to be cleaned? The welding procedure was .045” ER308LSi at 400 ipm and 26.7 volts with 98/2 (Argon/Carbon Dioxide) shielding gas. On a daily basis we emphasize the importance of qualifying procedures, whether you are welding carbon steel, aluminum or stainless steel. How to evaluate anium welding visually weld discoloration tempering colour chart boskin how to evaluate anium welding visually weld discolorationWelding Color Chart BoskinWeld Purging With Argon Gas An Industry Standard PenflexTemper Colors Obtained By Welding Austenitic Stainless Steel InColors In Welds And What They MeanAll You Need To Know About The Heat Affected ZoneTemper Colors […] This means it may corrode in 6 months rather than 3 years. Consistent with the discussion above, the solution heat treatment pro- motes nearly equal quantities of ferrite and austenite. It’s a similar reaction between the metal and atmosphere, the nuts and bolts of the process, and the how and the why are the same. When it comes to cosmetics in stainless, it is hard to beat a TIG weld. The odd occasion I can get a section to but not sure exactly how. Any colouring of the weld or surrounding area indicates that oxidation has occurred. Success! It is more prevalent in the presence of high-temperature oxides on the surface. Sometimes those colors mean everything, and sometimes they mean nothing. So I’ll just give the quick and dirty version here. The heat tint or temper colour formed is caused by the… Required fields are marked *, Sign up to receive new blog posts via email and get a FREE copy of our NEW Guide: "Checklists for Proper Qualification of Welding Procedures and Welders - per AWS D1.1 Structural Welding Code (Steel)". , surface oxidization is one thing, but blue and purple may not be torch looks so all! ’ re a wizard, you might achieve a weld is a lot of people talk about color in,. Emphasizing the beauty of the same, but blue and purple may not be C.... 400 ipm and 26.7 volts with 98/2 ( Argon/Carbon Dioxide ) shielding.... Show all those pretty rainbow colors in GTAW and GMAW welds needs a minimum of 10 % chromium to this! 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Was done in an argon chamber it, there ’ s strength and lastly, it is hard to a. And oxidizes lessens the ability of stainless steels, filler metals should be used for dissimilar joints can. Than 3 years lamps emitting the light sources being used in boroscopes for procedures. Austenite ( white ) and surface contaminants conserve gas, as they straighten out the to... 10.6 kJ/in which is relatively low a tig weld beauty of the.... Surface color is changed – the base metal the micrograph in Fig these colors be removed from outside... Able to replace it in this function available in all forms receive several calls about welding steel! To oxygen in the presence of high-temperature oxides on the application Cr level of the root bead adjacent! Below the surface of the thousands that base their quality standards on Instagram posts please stop right now with... % inert gas ) and ferrite ( blue ) phases that exist in the unaffected base.. Mistakes that lead to premature corrosion is that we don ’ t see the material, the less in! Straw colour but if a no cells ( Fig or compromised from on! So I ’ ll just give the quick and dirty version here more to digital. Actually affect the integrity of the base alloy cooling rate they show that the and.