Joshw Posted July 24, 2020 Share Posted July 24, 2020 I know the difference between mild steel and high carbon steel during a spark test means high carbon steel puts off sparks that fork and look like fireworks while the mild steel tends to have much duller less impressive sparks. My question to all the way more experienced blacksmiths on here is... has anyone found a good rule of thumb for identifying different high carbon steels from spark tests? I use almost exclusively salvaged metal in my forge and I know different metals prefer different heat treats. I know springs from cars are spring steel, tire irons are tool steel etc. but a lot of what I use is scrap from a metal fabrication shop and I have no idea what most of it is. Any tips for identifying scrap metals would be most appreciated. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 24, 2020 Share Posted July 24, 2020 Nope. If you become familiar enough with the steel you collect you can make a good guess but spark testing is at best an approximation and zero indication of other alloying metals. Sorry, you'll have to do it the way anybody using salvage does it. Spark test to rough sort then make test coupons and determine the best heat treatment for the steel and project. Smiths have been doing that since the dawn of the iron age. Even the spark test, low carbon steel or iron won't make a spark when struck with flint. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Glenn Posted July 24, 2020 Share Posted July 24, 2020 BP0020 Spark Testing Quote Link to comment Share on other sites More sharing options...
Frazer Posted July 24, 2020 Share Posted July 24, 2020 If you get an XRF scanner you could identify anything you want! Might have to break open your piggy bank though... I'd go with Frosty's suggestion first Quote Link to comment Share on other sites More sharing options...
dickb Posted July 24, 2020 Share Posted July 24, 2020 I get a lot of cut offs/drops/ etc from a machine shop They know exactly what kind of steel it is. It's usually color coded or marked with a magic marker. You can ask them. Might not work if you are dumpster diving Quote Link to comment Share on other sites More sharing options...
anvil Posted July 24, 2020 Share Posted July 24, 2020 Spark testing works as a comparative means of testing. Get some known samples of steel from your source. Mount them on a board and lable them. Then when you get an unknown piece of steel, test the unknown pattern against your known samples. Quote Link to comment Share on other sites More sharing options...
pnut Posted July 24, 2020 Share Posted July 24, 2020 Every time I get a piece of known steel I cut off an couple inches and label it for future comparative testing against mystery steels. Pnut Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 24, 2020 Share Posted July 24, 2020 If you can get a group of smiths together and everybody buys 1 3' piece of different steels and cuts it into samples and trades it can help to get your sample set grown faster. Note: STAMP the alloy into the steel; it's amazing how fast markers and paint can disappear in a busy shop. Also; be very careful about colour coding as different shops or suppliers use different codes! Quote Link to comment Share on other sites More sharing options...
anvil Posted July 24, 2020 Share Posted July 24, 2020 Excellent ideas! I should of thought of that long ago. Sometimes being a recluse has its drawbacks. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 24, 2020 Share Posted July 24, 2020 Perhaps we should engineer a sample trade at Quad-State 2021? Quote Link to comment Share on other sites More sharing options...
JHCC Posted July 24, 2020 Share Posted July 24, 2020 Works for me. I've got 1080, 4140, and H-13. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 24, 2020 Share Posted July 24, 2020 We need to decide on flat or sq or rod and how long of pieces. I was thinking of buying some new 5160 and perhaps 1020. I have a large amount of A-36 but it's variability makes it hard to have a definitive sample. I actually have a lot of oddball stuff but in sizes hard to work with; like 2345, it was part of a discarded sample library from a welding school and each chunk is stamped with the alloy. They are sort of like short lengths of 2x4's in steel. I mainly snagged the higher C alloys as I was more focused on blades back then... Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 24, 2020 Share Posted July 24, 2020 If you use strip stock, say 1/8" x 3/4" x 2" it's easy to hold at the grinder, hang from a drilled hole and read the stamped ID. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 24, 2020 Share Posted July 24, 2020 I think I'd like the samples a bit longer to allow for frequent use at the grinder...Hmm a garden rake would make a nice sample rack too. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 24, 2020 Share Posted July 24, 2020 Quote Link to comment Share on other sites More sharing options...
pnut Posted July 25, 2020 Share Posted July 25, 2020 21 hours ago, ThomasPowers said: STAMP the alloy into the steel; it's amazing how fast markers and paint can disappear in a busy shop Very true. I had to put them in Manila envelopes because the paint marker was wearing off. I don't have stamps but I have an electric engraver. Same result. That's actually something I can do today. Pnut Quote Link to comment Share on other sites More sharing options...
Paul TIKI Posted December 17, 2020 Share Posted December 17, 2020 So from a practical scrap hound point of view and not for precise identification, would some of you curmudgeons weigh in on a testing sequence shown by John from Black Bear Forge in one of his videos (I admit, I'm Hooked) He does a spark test first and show to compare against test coupons but he stresses that the spark test is useful but it is also somewhat subjective. Then he does a file check, followed by a heating the test piece to critical temp and then letting it air cool. Then he file checks it again. If it is hard to file you might have air hardening. He also puts it in a vise and give it a whack to see if it got tougher. Then he repeats with oil, and then water.. I know this is not super precise but do you guys think this would be pretty useful way for a beginning smith to be able to categorize the scraps they have harvested? Do any of you curmudgeons have a different process for dealing with scrap that doesn't get into to more precise comparisons? And if I missed it in another part of the forums could you point me the right way please? Thanks again! Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 17, 2020 Share Posted December 17, 2020 Generally you don't find the weirder alloys in the scrap stream as they are not common and are expensive enough to be scraped as themselves to the metal makers themselves. You do sometimes run into them. My local scrapyard has some jet engines in it; of course there is an ongoing lawsuit over them... So as I am interested in blades; I generally will do a heat, water quench and break test as easiest. If it shatters in quenching or is very hard (file test); I will repeat with a warm oil quench as that is what I prefer to use with blades. Quote Link to comment Share on other sites More sharing options...
Paul TIKI Posted December 18, 2020 Share Posted December 18, 2020 so, same tests in reverse order. that makes a certain amount of sense. I need to learn more about heat treating. See if you can get the bearings out of the jet engines. Anything that can stand up to those rpm has got to be tough. I have seen the results of a bearing failure, not up close, but it was a subject of a safety thing at my employers a few years ago. imagin being the guy in the cockpit running up the engine on a jet that is vlose to certification. suddenly boom and a 3 foot long hunk of glowing red shrapnel punches through the wing barely missing the fuel cells and lines. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 18, 2020 Share Posted December 18, 2020 Well evidently they were scrapped when they should have been returned. The scrapyard owner would be happy to sell them back; but at a lot higher price than he buys at! Currently they are fenced off waiting for the lawsuit to wend it's way through. I doubt I could effectively forge or heat treat bearings of such alloys! Now if I can find some more buggy springs... Quote Link to comment Share on other sites More sharing options...
Paul TIKI Posted December 18, 2020 Share Posted December 18, 2020 I can imagine. 10 years ago even small jet engines the sort of which drive turboprops cost several hundred thousand. Aircraft companies don't even make their own anymore. Most come from Pratt & Whitney, GE, Honeywell and even Rolls Royce. Lots of titanium and titanium coated parts in there. I remember seeing some large bolts in our inventories for those things. 1 inch thick and 8 inches long, solid titanium. More than a hundred bucks a piece at our cost IIRC. I do know that a big part of the cost comes with the little piece of paper from the poobahs at the FAA. Quote Link to comment Share on other sites More sharing options...
Chris Williams Posted December 31, 2020 Share Posted December 31, 2020 On 12/17/2020 at 10:46 PM, Paul TIKI said: See if you can get the bearings out of the jet engines. Anything that can stand up to those rpm has got to be tough. I have seen the results of a bearing failure, not up close, but it was a subject of a safety thing at my employers a few years ago. imagin being the guy in the cockpit running up the engine on a jet that is vlose to certification. suddenly boom and a 3 foot long hunk of glowing red shrapnel punches through the wing barely missing the fuel cells and lines. Most engine bearings that I encountered were 52100. There were some other alloys used, but nothing particularly exotic. It doesn't have to be a big piece of shrapnel to ruin your day, either. I've seen crashes from smaller shrapnel (such as a single thrown turbine blade) cutting fuel lines as well as from shrapnel hitting a remaining good engine. Bigger chunks from a fragmenting disk have tremendous energy, and are even more destructive. Even though I know the odds of an event are miniscule, I don't like sitting in the plane of rotation of the turbines or compressors. Quote Link to comment Share on other sites More sharing options...
Paul TIKI Posted December 31, 2020 Share Posted December 31, 2020 On the plus side to my story, they sussed out the problem, fixed it and there are no incidents that I know about since then. I know there is a lot of titanuim for things like wing mounts and engine mounts but I really don't know about it's use in the moving parts area. I'm not a mechanic, but I have had a lot of opportunity to look around in the stock rooms when I was working on an inventory control and reduction project in the flight test area. The fun part there was arguing with old engineers who thought that we should keep expensive parts because they were expensive, even though the aircraft they were for had undergone 2 significant re-designs for that part (like going from 4 prop blades to 6). Or that we needed to keep the water ballast system for a really old aircraft in spite of the fact that the seals were all bad and it had become a home for spiders and other critters. My favorite was the Rolls Royce engine. It was at least one generation out of use and had been badly scavenged. I think we ended up donating it to a local tech school just to get the dang thing off the books. Quote Link to comment Share on other sites More sharing options...
Chris Williams Posted December 31, 2020 Share Posted December 31, 2020 It's good to hear that they fixed the issue. I saw several design features that had been incrementally worked on (with improvements and otherwise) for years or even decades without adequate resolution. I was typically working with stuff that was one or more generation old, and the rotating compressor parts were typically titanium alloys. I don't know what is in the current generation engines. I haven't worked with aircraft in years now. I guess that keeping expensive parts might make sense if you have a cost+ contract or you make a percentage on the parts. I was always on the using end and didn't appreciate the expensive parts made from Unobtanium. Quote Link to comment Share on other sites More sharing options...
evfreek Posted December 31, 2020 Share Posted December 31, 2020 I use separate tags made out of aluminum and stamp those. The links are copper. Kind of like a blacksmith's keychain. Quote Link to comment Share on other sites More sharing options...
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