Aaron J. Cergol Posted July 22, 2011 Share Posted July 22, 2011 Hi all, simply put, what is the difference between A36 ad 1018 mild? I have a railing job to do-just some basic twisted spindles and scrolls, and I see that A36 is substantially cheaper and I'm wondering if it will work for light forging operations. Also, what about forge welding? Aaron Quote Link to comment Share on other sites More sharing options...
Ric Furrer Posted July 22, 2011 Share Posted July 22, 2011 Aaron, A36 is not an alloy designation, but rather signifies its minimum shear PSI 1018 is a chemical designation....about 18 points carbon and no other alloy additions of any note (the first number is the alloy group and the second number..in this case zero... is the percentage of that alloy group). The diffidence is one can be anything that meets the PSI min..the other is a specific something. In general you will have no issues using A36 for architectural use, but keep in mind that you should not quench your electric welds. Also, do not quench any other part of the project unless you are OK with the potential..potential I say..of that part getting hard. I have had some A36 which was tool steel of rather high alloy, but met the PSI minimum. Some can not be drilled or sawed unless annealed, but most is just fine and you will not see any issues. Ric Quote Link to comment Share on other sites More sharing options...
MattBower Posted July 22, 2011 Share Posted July 22, 2011 A36 is a performance standard with a fairly loose allowable range for chemistry. The composition standard for 1018 is tighter. In practice, I've been told that 1018 is commonly sold as A36 (since it meets the standard), and I have experienced that myself. A36 at the minimum allowable strength for that grade will be substantially weaker than 1018. Of course a lot of A36 probably exceeds the minimum by a good bit. Some people have said they've experienced problems forge welding some batches of A36. The explanation I've seen for this is that the permissible chemistry for A36 allows for inclusion of some elements that could cause welding problems. A lot of A36 will forge weld just fine; it's just the occasional batch or even individual piece that seems to cause problems. Quote Link to comment Share on other sites More sharing options...
MattBower Posted July 22, 2011 Share Posted July 22, 2011 A36 is actually the name of an ASTM standard for structural carbon steel. (No doubt they chose "36" due to the minimum yield strength requirement.) It does have a chemical composition component, which includes a maximum carbon range of 0.25%-0.29%, although I don't really know how to square that with the reliable reports of very hard A36. Anyway, here's the standard: http://www.burwill.com/download/product/A36.pdf Quote Link to comment Share on other sites More sharing options...
Frank Turley Posted July 22, 2011 Share Posted July 22, 2011 I don't think that I've forged 1018 in years, if ever. We used to get 1020 off the racks, but nowadays most everything at my steel supplier is A36. With A36, you'll notice that on 3/4" and under, manganese is not added as an alloy. It is added on 3/4" up to impart strength. So on pieces 3/4" and less, the carbon content is supposed to not exceed 0.26%. The difference between 1018 and 0.26% is 0.08% carbon. That's not too big a deal for our kind of work. However, when you reach 0.30%, you're into a medium carbon steel which can be hardened. Nearly all my work is of A36, and I forge weld it without trouble. I don't use excessively large sparking heats when welding, and that seems to help. Lots of my welding heats emanate no sparks. http://www.turleyforge.com Quote Link to comment Share on other sites More sharing options...
John McPherson Posted July 22, 2011 Share Posted July 22, 2011 The problem is not the specs for A36, the problem is unscrupulous vendors who will sell you whatever they have on the shelf and *tell* you that it is A36, or whatever you asked for. Always state up front that you need the "certs" (certified mill report with chemical analysis of each heat number, or batch) for each lot of steel that you purchase. That is a traceability requirement for ISO standards, so honest merchants will have the driver hand it to you upon delivery. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 22, 2011 Share Posted July 22, 2011 A36 is generally a tad harder under the hammer and so not as good for very "florid" ornamental work where "pure iron" might be just the thing. However it's what mostly gets used these days. As mentioned don't quench---normalization is far better. With A36 I like to not have a quench tank handy just to make sure. And by the way 30 points is not some magic number, it's just one chosen for convenience to mark the change from mild to medium so as you go up from 00 towards 30 points of carbon stuff gets increasingly "medium-like". Now the eutectic concentration does represent a change! Quote Link to comment Share on other sites More sharing options...
Aaron J. Cergol Posted July 23, 2011 Author Share Posted July 23, 2011 Well this is excellent news! Thanks all for the help and input. This saves me an awful lot of money. and also, duly noted-do not quench. So just to clarify, the consistency may vary from piece to piece due to the lot having different Shear PSI ratings? If that's all I have to worry about that's no real concern. I read some more and it seems to fall into the 1010-1035 range for carbon, is this correct? Ric-thanks for the info. Long time no talk, I had shot you an email a while back, then my email was hacked. Let's stay in touch, I'd love to come out to your place again and help you with anything if you need it. Also you're more than welcome to my shop in Milwaukee. We can make some hammers! Aaron Quote Link to comment Share on other sites More sharing options...
pkrankow Posted July 23, 2011 Share Posted July 23, 2011 You may have part or all of a bar go to cottage cheese on you as you work it hot. This may be "corrected" by working it cooler, which may be impractical. When you get a stick like this, it is best to put it aside for cold worked items and consider it a loss, however you will not identify it until it acts poorly at heat. This is often causes by excess sulfur and phosphorous in the iron, and it may be limited to a small section of a bar. Cutting away the failed section and trying again is always an option. Phil Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.