Cutting forged steel with O/A

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Today I had my first occasion to torch-cut some forged steel - but I didn't realize that was what it was.  I had this chunk of what I thought was some kind of rolled bar steel, about 14mm thick and 2.5" wide, that had come from the metal scrap yard at our local "transfer station".  It was rusty and scaly in the extreme, but I used the angle grinder with a wire brush-head and got down to some sheen.I guess the bar was something from a tractor chassis or something.  ??Well, it cut a little more predictably and cleaner than cast iron but more ragged than rolled steel.  Tiny blobs were falling off in the kerf, but not nearly as messily as with cast. Is that pretty much the situation always when torch-cutting forged steel?  Or are there any tricks the savvy guys use?  If you did have to cut this kind of material, would you choose a cutting disc on an angle grinder instead of a torch?  Or just save the torch for when very crude cuts don't matter?Thanks.
Reply:It probably wasn't forged steel if it cut badly. Forged steel is still just steel and cuts very nice with the torch. It could have been a blended steel/ iron cross. Foreign tractors use this a lot and have to be welded with rods for cast iron.Also I don't think a torch is for crude cuts. If you make crude cuts with one then you need practice and some one to show you how to set it up for good cutting.
Reply:Originally Posted by BobAlso I don't think a torch is for crude cuts. If you make crude cuts with one then you need practice and some one to show you how to set it up for good cutting.
Reply:Buy the way, cutting cast with OA is not even considered unless its an emergency and then it takes a special process.  Mac.
Reply:Joel BC  Can you be a little more specific about why you described your piece as forged-steel, ie. median seams, compound shape, surface features . . . What, in its character, looked like it was a tractor, or like part.    There are a number of steels that behave this way when cut with OA. Forged maybe a red-herring, but could be important.Please elaberate.Opus
Reply:Originally Posted by OPUS FERROJoel BC  Can you be a little more specific about why you described your piece as forged-steel, ie. median seams, compound shape, surface features . . . What, in its character, looked like it was a tractor, or like part.    There are a number of steels that behave this way when cut with OA. Forged maybe a red-herring, but could be important.Please elaberate.Opus
Reply:Joel BC  -  OA cutting characteristics vary with iron analysis.    Wrought-Iron, essentially pre-steel, behaves as you have described because of slag inclusions in the interstitial grain boundaries.  Wrought-Iron as a raw material faded by the 1920's; but stillsurvives as scrap because it oxides slower than steel.Another poor cutting 'tractor looking scrap' [and common] is  steel with varying % of manganese, alloyed for impact with-out brittleness, ductility, heat treat and other . . . . .   There are other 'tells', but without knowing your exact cuttingproficiency cannot be identified over the phone.Opus
Reply:Do a spark test by observing the pattern, colour and length of sparks from a grinder."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Originally Posted by noriteDo a spark test by observing the pattern, colour and length of sparks from a grinder.
Reply:Google "spark test".  Wiki has an article on it.  Then switch to google images, lots of photos and diagrams to show results."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Originally Posted by Joel_BC. . .I had this chunk of what I thought was some kind of rolled bar steel, about 14mm thick and 2.5" wide, that had come from the metal scrap yard at our local "transfer station".  It was rusty and scaly in the extreme. . .
Reply:denrep  -  Steel, what steel?Either; I understand all of your quotes and comments, or I don't understand all of your quotes and comments.With total respect for post postulation, could you please reiterate the clarification of your premise.Opus.
Reply:Originally Posted by OPUS FERROdenrep  -  Steel, what steel? What steel or which steel? With reply #11, I quoted the word "steel" as used by Joel_BC and I also used the term "steel" myself. If you would kindly specify by the particular use(s) of "steel," or use a quote, I would be happy to try to address "what" steel I was referring to.  Either; I understand all of your quotes and comments, or I don't understand all of your quotes and comments. What of the possibility that you understand some of my quotes and comments?  Or is that possibility addressed with the later?With total respect for post postulation, could you please reiterate the clarification of your premise.  With all due respect, I am unable to respond to the above without some of your own clarification. For example, would not to "reiterate" the clarification of my premise,  indicate that I had previously clarified same, and would be doing it again? If so, considering your second paragraph, apparently clarification was not sufficient. However, having previously clarified that the premise of your own response is in need of clarification, at this point I can only speculate on your concern. For example, when you write "post premise" do you actually mean, "post-premise" as in following a premise? Or possibly with "post premise" do you imply "post" in  the context of "post" being a posted response.Again, if you could kindly clarify by specifying the areas of your concern, I would be glad to reiterate the clarification of premise specifics. Opus
Reply:When denrep breaks out the blue you know he's had a really good bowel movement  -  Opus