Kerry D Posted April 6, 2012 Share Posted April 6, 2012 I have a couple of questions about cutting steel found in ag applications. First off, is there a general rule about the kind of steel found in swather knife sections (a.k.a. sickle sections), or would I be better off asking the parts person when I buy the part if he or she knows what kind of steel the sections are made of? Secondly, as I am a hobbyist and mostly got into this as a way to get use out of the scrap steel we have around, I like to use worn parts to make things. So when I saw the straw chopper blades from the combine had to be replaced I thought I'd try to find something useful to do with them. Then I found out that they're likely T9 steel and, looking at the AISI sheet on T9, I feel that T9 is beyond my forging skill level at this point. The question now is what can I do with this stuff, or is it best to go to the scrapper? Here's a link to the spec sheet I found if you're wondering what the heck I'm talking about: http://www.steel0.com/AISI_T9.htm Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 6, 2012 Share Posted April 6, 2012 I doubt those parts are anything more than 1085 carbon steel. It is rare for anything but really heavy equipment to use the more exotic chromium steels. That being said, I'd like to try some of that stuff. The best thing for you to do, at least for starts is get some sample pieces and do spark test with it. There are charts available to help identify steels by there spark. They aren't real accurate but will help get you started. Get some sample pieces that you know what it is and compare the sparks. Forge out a small piece, heat to nonmagnetic and quench in water. Put it in a vice and break it (wear safety glasses) and inspect he break. If it doesn't break it isn't knife material, and if the broke steel has a grainy texture take note. You want it to look like satin. I like playing metal detective, it's fun, but you want a lot of the stuff as it may take you a while to work out how to harden and temper it. I Quote Link to comment Share on other sites More sharing options...
Kerry D Posted April 7, 2012 Author Share Posted April 7, 2012 I'm only going on what the parts man told me was made of, so you might be right but I'd hope he knows what he's talking about. I can try to forge it, but if it is T9 then I won't be able to work it as per spec, my fire control isn't good enough to soak at those temps consistently. But, like you said, I'll likely have as much as I want so that if it is actually something I can work with then I'll likely have a steady supply. edit: I posted this assuming that you were talking about the chopper blades, but if you were referring to the knife sections then that's about what I expected, something in the 1060 to 1080 range, forge weldable and reasonably nice to work with. Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 7, 2012 Share Posted April 7, 2012 T-9 looks like it is as much fun to forge and 52100. Play around with the lower carbon stuff and get aquanted with how it feels under the hammer. With a little experience you'll get to where you can tell how good the steel is for a knife just by shaping it. Generally, the easier it works the lower quality for knives. I wouldn't mind getting some of that T-9 and experimenting with it. I just love taking junk and giving it new life. Quote Link to comment Share on other sites More sharing options...
Kerry D Posted April 7, 2012 Author Share Posted April 7, 2012 Well, if you're interested, and the parts man is right, these are the straw chopper blades off of a John Deere 9600 combine. There's a boat load of them so if you know any JD dealers or combine specialized mechanics you can likely get as many as you want. I'm a bit far from you to ship 'em ;) Quote Link to comment Share on other sites More sharing options...
Chuck_Steak Posted April 8, 2012 Share Posted April 8, 2012 I do chemistries at work on the strip material that is used to produce the the triangle blades for a sickle bar. The blades are 1038 carbon steel and the are heat treated to around 40 HRC. Quote Link to comment Share on other sites More sharing options...
MOblacksmith0530 Posted April 8, 2012 Share Posted April 8, 2012 WOW, on ths sicle bar teeth, I would have put them a lot higher in carbon content than that, Do you know why they use the 1038 and why so soft? Sorry to hijack the thread but am real curious on this one. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted April 8, 2012 Share Posted April 8, 2012 I would get some and mess with it, if it is free. You may find the material is different that it is believed to be. Phil Quote Link to comment Share on other sites More sharing options...
Chuck_Steak Posted April 9, 2012 Share Posted April 9, 2012 MO, I think the hardness and material is just a compromise to get good toughness and the cheapest material. I don't know the specifics for the material choices, as we are a third party lab. The blades are still relatively tough (we also do some CVN's of the blade materials) but have the hardness and wear resistance for good performance in the field. You could probably make a better blade out of a higher carbon or high nickel alloy steel or a virtually indestructible blade out of a tool steel, but for a replaceable component, the 1038 works satisfactorily and it keeps the price down on a large scale production. Quote Link to comment Share on other sites More sharing options...
Junksmith Posted April 9, 2012 Share Posted April 9, 2012 Free steel is free steel. No law says you have to make a $400 hunting knife out of it. If it's workable then it's good for practice and projects that aren't material specific. Garden tools maybe? Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 9, 2012 Share Posted April 9, 2012 I wonder, do they hard face or make them so they can be hard facing rod? Quote Link to comment Share on other sites More sharing options...
Toreus Posted April 10, 2012 Share Posted April 10, 2012 The one's I've worked on have been carburized. I'm always surprised at how shallow the hard layer is- IIRC the last ones I saw were carburized to about 0.5-0.6mm Quote Link to comment Share on other sites More sharing options...
Chuck_Steak Posted April 11, 2012 Share Posted April 11, 2012 None of the sickle teeth i've worked with have been carburized or hard faced. Many of the combine or big chopper blades i've seen, however, have been either carburized or have had a thermal spray hard facing. Slightly off topic but.... The hard facing is kind of interesting because it makes the blade self sharpening. The hard facing is generally a tungsten carbide in a cobalt or nickel matrix so it is really really wear resistant. The thermal spray will be applied to the flat cutting edge. The bevel is made in the blade steel and the steel is left without a hard face or case hardening. This results in the blade material wearing away along the bevel, but the hard facing stays intact. So the small layer of hard facing effectively acts as a sharper edge, maintaining the cutting edge. So with regards to how this pertains to forging...If the blade has a slightly rough layer on the flat side adjacent to the cutting edge, its probably a thermal spray and may forge funny. (chip, fall off, etc). Doesn't seem like it would be a big deal tho. Might make an odd welded billet though. Quote Link to comment Share on other sites More sharing options...
Kerry D Posted June 9, 2012 Author Share Posted June 9, 2012 Wow, I got busy with my real work and lost track of this thread, but thank you all (especially Chuck_Steak) so much for the great information! I was actually looking to repair a dandelion digger that has worn away with use, so med carbon steel will work at least as well as high carbon steel. Now the challenge will be to find one that has lived out its usefulness on the haybine and is still in good enough shape to use as a part. Quote Link to comment Share on other sites More sharing options...
Cowboy Todd Posted December 21, 2021 Share Posted December 21, 2021 Looks like I'm 9 years late on this, but if I'm still reading this, others may, too. I just forge welded 6 sickle bar mower sections together to make about a 3/4" triangle of steel. It was very easy to weld. Then the easy stopped. I've never gotten anything so hot and beat it so hard for so long to have so little to show for my work. I was swinging a 4 pound cross peen and I can put some back into it and it took me over 3 hours to get it from 3/4" to maybe 3/8" and increased the length by half. It became practically futile after a while, but my ego kicked in, so it IS gonna be something sooner or later, but I think I'll take a break and throw some pressing anvils on my wood splitter first and make a hydraulic press. It is definitely not 1038. After reading the sheet on the T9 I'd say it sounds a lot more like that. If I ever do get a knife made, it will be utterly indestructible! Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 21, 2021 Share Posted December 21, 2021 By sections do you mean blade pieces? How old were they? The older ones are more likely to be a plain HC steel and not some weird modern alloy. I assume you have already done the quench and break test to see if they would make a decent blade. It's a good sign when a billet becomes harder to forge---it means it's welded well and my even have equalized carbon content! We've been welding up some drive chain lately and there comes a time where a friend on the 8# sledge is a big help squeezing all the cavities out. Don't forget to preheat your dies before working HC. (Press on a thick chunk of hot A-36 a bit; even better if you can work the A-36 into a project you are making so you don't waste time, fuel.) Remember winter and HC steels are NOT friends! BTW "indestructible" knives are usually not real good ones; just indestructible... Note that if it's all one alloy the patterning will be subtle at best. I'd stack the blades up with pieces of large bandsaw blade between them to get some Ni highlights. A nice shear will cut the bandsaw blades into the same shape as the cutter blades. Quote Link to comment Share on other sites More sharing options...
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