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Up Topic Welding Industry / Technical Discussions / ASTM A513 for Handrail Applications???
- - By swnorris (****) Date 04-21-2004 20:49
Due to the continuing increases in steel prices, early last month I purchased a truck load of 1 1/4" (1.66 o.d.) pipe produced in Mexico at .89/ft, which is due in on 4/22. I specified ASTM A500 Grade B, and since I was a little apprehensive about such a purchase, I was adamant with the sales office in Texas that I would indeed receive A500B pipe. The shipping document and mill test report were faxed to me today and they indicate that the material will be grade ASTM A513, which I am not familiar with nor thrilled about. I know that the minimum yield stress for A500B is 42 ksi (as opposed to 30 and 40 ksi for the two heat numbers on the MTR), and the minimum tensile stress for A500B is 58 ksi (as opposed to 49 and 55 ksi for the two heat numbers). This is just one of my concerns. Another would be is this A513 suitable for bending and galvanizing? Still a couple other concerns are that although this is for a handrail application, we are bound by contract documents to produce welds in accordance to D1.1. In D1.1, A513 is not a prequalified base metal, so I would have to go through the procedure qualification process, etc. The A513 pipe would have to also be able to withstand a 200# load per foot to meet the OSHA specification, which would require further testing. A500B is a cold formed pipe, and I found out by researching the ASTM site that A513 is ERW. I'm guessing that this doesn't have any bearing on anything, but my question is provided we can get everything approved, what would be the best mig wire and shielding gas to use? We are currently using .035 wire and 98% argon and 2% oxygen. I also found in researching the A513 spec. that it could be manufactured from a variety of grades that may be either carbon steel or an alloy steel, which makes me wonder if there any weldability or ductility issues that I need to be concerned with. I've got a call in to the sales office in Texas, I just thought I'd bounce this off you guys while I'm waiting on a return call.
Parent - - By GRoberts (***) Date 04-21-2004 21:37
I looked up A513 here, and the tube can come in many grades, from 1008 to 4140 & 8630. Your MTR should give you the chemical analysis though. The specification provides no mechanical property requirements. Weldability and bendability will mostly depend on the grade you were supplied, and the quality of the weld. You are correct though in that A500 tube can be ERW also, and normally is unless seamless is specified. A513 steel can be made by any melting/refining process, so you may have rimmed, or some other type of non-killed steel. If that is the case, use a highly deoxidized wire, such as ER70S-6, or a flux cored wire designed for welding over rust/scale. If your CMTR has Al, Ti, or Zr in it, you should be ok that way though. If you post the chemical composition from the cert, more information about your pipe could be provided.
Parent - - By swnorris (****) Date 04-22-2004 12:19
Thanks for the information, GRoberts. There are actually three heat numbers on the MTR. The heat analysis is as follows:
C% = 0.0900, 0.0500, 0.0890; Mn% = 0.3510, 1.1200, 0.3450; P% = 0.0069, 0.0130, 0.0099; S% = 0.0060, 0.0040. I don't know if this would help you, but the hardness is 50 HRB for all heats, and the elongation is either 20 or 21%. Incidently, we are using ER40S-6 mig wire, .035 diameter, with 98/2 shielding gas. Thanks again for your help.
Parent - By jwright650 (*****) Date 04-22-2004 14:13
Hi swnorris,
I was curious why the Manganese (Mn) levels you listed were varying?, possible typo on the MTR?
In particular, the middle figure in relation to the other two.(.3, *1.1*, .3)
John Wright
Parent - - By GRoberts (***) Date 04-22-2004 15:51
It looks like your first & third heat could conform to either grades 1008, or 1010. If the Mn number is correct for the 2nd heat at 1.12, then it does not conform to any of the grades. The lowest grade that allows 1.12 Mn is 1024, but it has a minimum carbon of .18%. Except for the wierdness of the Mn on heat#2, they look like they should be pretty weldable as the P & S are low, and hardenablity is not a concern at all. As for bendability, as long as the ERW weld holds together, it looks soft & ductile. The 50 HRB seems a bit fishy though. For a 55 ksi heat, HRB should be around 64. 50 HRB corresponds to about 40ksi tensile strenght, which is very low even for mild steel.
Parent - - By swnorris (****) Date 04-22-2004 17:14
jwright650/GRoberts,
I've got a call in to the sales office to verify the Mn percentage. If the Mn percentage is correct, GRoberts says that it would not conform to any grades, so I would obviously need to reject the bundles with that heat number. Out of curiosity, what other problems would that pose? He also says that the lowest grade that allows 1.12 Mn is 1024, but it has a minimum C content of .18%. My particular heat has a C content of .0500. Also he says that the 50 HRB for a 55 ksi heat should be around 64 ksi, as 50 HRB corresponds to about 40 ksi tensile, which is very low for mild steel. Could ya'll please comment on some of the problems this could create, so that I can pass it on to the boss, in case he gets an idea to keep material from the heat in question? You guys help is greatly appreciated, and thanks.
Parent - By GRoberts (***) Date 04-22-2004 19:51
I think your main problems would be:

Since a couple of things on the certs seem in question, does the material really meet the requirements that they say they do? Only further testing would determine whether the certs are correct or not. Basically, did you really get what they say you got?

Is the material strong enough to meet the design requirements? The handrail, I'm sure was not designed around the A513 spec. pipe that has no mechanical property requirements. If you can verify the strength of the pipe, you may be able to get an engineer to accept it, however, with the lesser strength, the allowable span between posts may have to be shortened up.
Up Topic Welding Industry / Technical Discussions / ASTM A513 for Handrail Applications???

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