Dissimilar metals

admin

For a logsplitter knife.Used two 1/2 inch grader blade cutting edge welded together for the knife.T welded to a 10 inch I beam.Backed up with a 1 inch thick CRS gussett.Used lincoln 225 buzzbox, 5/32 6013 on 180 amp.That puppy only made it thru 7 1/2 facecords of knarly hickory; before breaking loose. The gussett held!gunna try to attach picts of the mess, and respectifully request any help, comments, flaming or whatever from the experts.Thanks in advance... if you could advise me how to succeed in sticking this fast for a few more cords. Attached Images
Reply:Originally Posted by ronkoFor a logsplitter knife.Used two 1/2 inch grader blade cutting edge welded together for the knife.T welded to a 10 inch I beam.Backed up with a 1 inch thick CRS gussett.Used lincoln 225 buzzbox, 5/32 6013 on 180 amp.That puppy only made it thru 7 1/2 facecords of knarly hickory; before breaking loose. The gussett held!gunna try to attach picts of the mess, and respectifully request any help, comments, flaming or whatever from the experts.Thanks in advance... if you could advise me how to succeed in sticking this fast for a few more cords.
Reply:ronko, my first thought is that your 6013 filler metal is a bit under strengthed for that grader blade. I would want to match tensile strengths. I'm not sure what the tensile is but would start at a E9018. Unless you can find out what it is.
Reply:Find a hardness tester and check the hardness, that will tell the Tensil of the material.  JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:Thanks Go1Can get 7018 AC no prob.Have access to ox/ac torch.  For preheating such a big piece, would it help to have a helper run the rosebud to cherry red for say 2 inches,  jump out and go to the other side, while i apply the root pass on that 2 inches, then swap sides and do another 2 inches.  Can't really picture keeping the whole 6 inches cherry and getting it welded at the same time. Preheat subsequent passes?Keep hot or let cool between passes?Last edited by ronko; 05-16-2008 at 04:34 PM.
Reply:Thanks qaqcme thinks i already figgered the 6013 was some of the prob, although it did hold the gussett OK to the structural I beam.
Reply:Sorry, weldgault, no way to test the hardness.  Harder than the shades of he## but not quite as hard as my head.
Reply:Originally Posted by ronkoThanks Go1Can get 7018 AC no prob.Have access to ox/ac torch.  For preheating such a big piece, would it help to have a helper run the rosebud to cherry red for say 2 inches,  jump out and go to the other side, while i apply the root pass on that 2 inches, then swap sides and do another 2 inches.  Can't really picture keeping the whole 6 inches cherry and getting it welded at the same time. Preheat subsequent passes?Keep hot or let cool between passes?
Reply:Gonna be hard ta bury this logsplitter inna sand,  but might hafta, if can't get this knife stuck back on there.  Do have a small asbestos (shhhh) blanket what came from a firetruck.  Also, since i'm burning my son's gas, can cool slooowly.How do i tell 600 degrees? Always wanted an excuse ta get an infrared thermometer.Do they go this high?
Reply:mine goes up to 2000f. the only issue that these seem to have is the when used on lighter metals like SS or AL the accuracy is out the window. Other than that they are great. My model only cost $80. A cheaper option is to get a temp stick from your local welding supply shop. Your blanket sounds like it will work fine.
Reply:Ronko, try Enco (I think use-enco.com). I have seen IR thermometers for less than $80.00. You can also go to your LWS and buy a Templestick in that range. Would it be possible to do a clip test on that hardened cutting blade to see if it is weldable using the process you've outlined?Yeah, yeah, I know you are a weldor too. But, are you a good one?
Reply:Nothing wrong with an asbestos blanket, just don't sit there and sniff it. As long as you don't inhale it shouldn't be a problem.
Reply:OK OK, thanks all.Gonna give ya'all a bigger view of the prob at hand.  Gonna post a pict of the entire setup, I Beam, gussett and knife assy.Disregard the date stamp and "other" distracting edifices left about my garage. Attached Images
Reply:You see the weld itself is fine, it is still stuck to the I-beam just fine.  The failure is in the heat affected zone HAZ of the hardened steel cutting edge.  This material is obviously highly hardenable, so the welding has created hard and brittle untempered martensite along the fusion line, and any little undercut, lack of fusion, or notch along the weld acts as a stress riser making it easy for brittle fracture to initiate.As others have said, you need preheat and slow cooling to prevent the brittle HAZ.  And as said, low hydrogen rod, 7018 is a good idea, but it must be new un-opened rod, or properly stored in a oven, otherwise it's no better or maybe worse than 6013.  Low hydrogen, low moisture rod is good for this application because it prevents hydrogen induced cracking, cold cracking, in high strength steel HAZ.6013 is made to operate with moderated moisture in the coating, it actually helps for the protective gas around the arc.  But 7018 is ment to be dry, so when exposed to air for too long it really picks up alot of moisture, maybe more than 6013?Preheat, weld with 7018, make the weld toe line very smooth, do not leave any stress risers, grind and blend if nessesary, slow cool.
Reply:IronkenDunno what a clip test is, but probably was NOT meant to be welded:  cuz, as you can see, it has square bolt holes made into it.  I cut two opposite ends of the grader blade off to get the two square bolt holes to line up. Intentions were to make another "T" knift in the future, to split logs 4 ways.  Some of the previous picts you can see, the blade actually shattered, rather than bent.       Wondered,  mebbe can't be welded (to hot rolled steel) at all?
Reply:If you are going to set up for welding that with E7018AC as suggested, (which I agree with), clean and grind within 2" of the weld zone, but preheat as much as 2' around and do so evenly. If you have a weed burner and propane tank, they work like a charm. When it is warmed up several hundred degrees or better, make several small passes cleaning inbetween each pass, then give it a dose of post heat, again with the weed burner. A rose bud on the oxy-acetylene torch is ok to substitute for the weed burner, just slower. Do not quench the hot steel with anything! Allow it to cool very slowly.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:You have the holes why not use them? After you reweld the piece add some side plates and bolt thru the holes to transfer more of the stress. How big are the pieces you are trying to split? The gusset looks short as a backer. If you are splitting large dia. logs I can see at lot of force being applied to the base welds.If you plan on making an X later you might just want to scrap the grader blade and pick up some other steel to make the wedge. I doubt you really need super hard steel for this aplication.
Reply:Thanks DSWThe knife is 14 inches tall and 5 1/2 wide.  I was planning on using the bolt holes to bolt ( and unbolt) the horizontal knife.   I may get logs as big as 30 inches or traditionally under 16 or so, which is just right for splitting 4 ways simultaneously.I'm beginning to wonder if i do really need such hard steel.   These were easily obtainable (neighbor) so i used them.  What kinda steel would i buy.   Regular flat HRS?   I think TSC or Northern sells knives for this application.Mebbe i'll just sharpen the gussett.  It's 9 inches tall.Last edited by ronko; 05-16-2008 at 06:51 PM.
Reply:Can you weld it flat? If so use 7024 as it has the most stretch of any mild steel electrode. It also cools slower so that should help. Asbestos will only hurt you if you inhale particles. Don't hit it with your grinder or run it through a shredder and you should be fine. I usually wrap stuff like this in a fire blanket to help slow cooling.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:I agree  with everyone  have welded many cutting edges  on  weed burner and e7018     this  is acool site  lots to learn
Reply:Why use a cutting edge? You aren't splitting rocks.
Reply:Thanks ya'all for the advise. Gonna try to stick 'er on there again with more preparation this time around.  V groove deeper trying to remove as much of the old as possible.General concensus is preheating before, during and after letting it cool very slowly by wrapping with a fireblanket.Use 7018.Also gonna try to jack up each side to 45 degrees so that can lay this T Weld in there better. Probably have it ground ready & waitin' for my son to help with the torch. Remind me to post picts back to let ya know how it worked out.
Reply:If you don't have a temp stick/probe you caan get an idea of the temp by the color of the metal. Darkk blue/purple should be close. Try a search of the site here there is probably a good description of heat and the color it makes. or do a google search.
Reply:Thanks AllShe's coolin' right now wrapped up in a thick asbestos blanket.Bought some 5/32 - 7018 and practiced yesterday sticking the two knives together to themselves.  Preheated with ox/acy till sharp edges glowed cherry (probably too much) and layed the 7018 in there, then hit it again with ox/acy to maintain temp. Wrapped that up and left to cool overnite.  This morning son helped me with the torch and a borrowed IR thermo to stick that hard blade onto the IBeam.  Thermo range was 425 F, so he'd heat it till went out of range, I'd hit it with 7018, then he'd heat it between passes while keeping previous welds warm.  Was not as pretty or as scientific as you'd like, but may have better chances of sucess than the first time.  Got some undercutting this time, so had to make and extra pass for that.  I'm getting pretty good at grinding;...some day mebbe i'll get better at welding.
Reply:These are not dissimular metals. That would be like steel to stainless etc.,.The second photo tells the story. Lack of penetration. The area to be welded must have a good fit up and be clean ground metal.The 6013 is a general purpose rod.The 7018 is a x-ray quality strutural rod.I agree about the use of 7024.You need to go have this welded by a shop with a 1/16 inch diameter wire feed 400 AMP machine. A structural iron shop.That small welder is just not enough for this job. Hope you do not get hurt if that thing lets go!!Originally Posted by Donald BranscomThese are not dissimular metals. That would be like steel to stainless etc.,.The second photo tells the story. Lack of penetration.
Reply:I agree PULSER.Sorry if i seemed police like. Sorry.There are a lot of issues here.I was taught not to try to weld HARDENED metal to un hardened metal.The hardened metal first would have to be annealed,then welded then heat treated. Also that is why you usually see hardened blades always bolted onto most heavy equipment. The best way for this log splitter to work is if the blade bolted (grade 8 bolts) onto the main frame so that the blade could be removed for sharpening.There are stickers on modern tractor trailer rig frames that, are hardened steel; that WARN against welding on the hardened steel frame.There are 3 types of steel that can be heat treated. AIR hardened, OIL hardened,and WATER hardened, The blade that he is using needs to have a determination as to what type it is. Reverse engineering so to speak.To me , from the photos shown, I just do not like the whole weldment. The sizes and thicknesses in respect to each other and the size (height) of the blade. If i was designing this, i would look at other log splitters and gather infoLike sizes and thicknesses,heights, and hydraulic components etc., then start building my log splitter.I would make that blade BOLT ONTO a steel weldment.
Reply:Originally Posted by daddyWhy use a cutting edge? You aren't splitting rocks.