The importance of good welding

admin

Just stumbled across this while surfing. This is Dave Wickham, a long time northeastern dirt Sprint Car racer. Dirt Sprint cars get into some pretty hairy looking flips, but nowadays there are "professional" chassis builders who build chassis with an emphasis on safety. Especially for "the fastest cars on dirt". At least you would think...Link somehow not working, sorry.http://web.a-znet.com/~dave1w/maxim_disaster.htmThere we go.Last edited by JeffB; 12-26-2009 at 01:32 PM.
Reply:He's fortunate to be alive! Proof that a good looking weld (it past visual inspection) isn't nesesarily a good weld.
Reply:the guy thatwrote the letter sounds like a scumbag..like that letter had been sent before. and the weld referred toas "glob" style looks cold, not tied in smooth at the toe, agree it doesn't looklike  a tig weld.
Reply:He got into a little back-and-forth with Maxim, who claimed all the welds were perfectly fine and up to spec. I may not be exactly an expert weldor, but isn't a proper weld usually stronger than the surrounding metal?
Reply:i'm noexpert either and expect  they will respond, this is a good question. seems to me if the weld is free of defects, and the same as the parent, and is a bit thicker,( i believe 1/8" over the parent is permissable?) then it is stronger. but the weld by dint of being there has also weakened the area  surrounding it.. haz...i guess like everything else in welding it is not a simple issue.
Reply:Maxim is a leading sprint car chassis builder and and Chuck Merrill is well respected in those circles.   (pun intended...)   Guys like Kinser and Dollansky drive Maxim cars.Failure modes in different wrecks are difficult to compare and the design itself of the chassis has a considerable influence on how much damage is done during a wreck.  One issue is the guy bought a car that was a school car and had been sitting for some time.  Tough to tell what kind of shape it was in and even though the owner says it wasn't it still could have been clipped. Clipped is the term that refers to replacing sections of a chassis, usually the front or rear.  I wouldn't throw Maxim under the bus.
Reply:You guys can correct me if I'm wrong, but I didn't see anything in any of those pictures that looked like a failed weld to me.  From everything I could see it looked like the welds held, but the material around the welds fractured for some reason.  Now, given that this car had been sitting for 2 years, I wonder if that 2 years happened to be out in the open somewhere?  If it had, then it's possible moisture accumulated inside the tubes and caused internal rusting or corrosion in areas that had been altered somewhat by the heat of welding?  Maybe the welding burned off some internal galvanization or something.  I don't know anything about race cars or the alloys used in them but what I see leads me to believe the material was at fault more than the weld.
Reply:Originally Posted by BrentDYou guys can correct me if I'm wrong, but I didn't see anything in any of those pictures that looked like a failed weld to me.  From everything I could see it looked like the welds held, but the material around the welds fractured for some reason.  Now, given that this car had been sitting for 2 years, I wonder if that 2 years happened to be out in the open somewhere?  If it had, then it's possible moisture accumulated inside the tubes and caused internal rusting or corrosion in areas that had been altered somewhat by the heat of welding?  Maybe the welding burned off some internal galvanization or something.  I don't know anything about race cars or the alloys used in them but what I see leads me to believe the material was at fault more than the weld.
Reply:It looks to me like a few things are out of the norm here. Let's start with the rust, there is rust inside the tubes. Water will always find it's way into frames. It does not matter if it is a bicycle frame or a race car frame or anything in between. What is done by any professional frame maker, in my opinion, is to make sure the water has a way out. Even better is to give it a way in AND out with removable plugs. Plugs can then be removed and WD-40 or something akin to it can be applied to prevent rust periodically.Now we move onto the welds. These things are not the prettiest and appear to have undercut. Undercut is the root of most cracks. Combine undercut with rust and you assure yourself of a break when placed under stress.Overall I see that the frame could have been done better, if only by a little. I see more that the lack of care and continued inspections for structural integrity are as much to blame for the failures. Here in a "Blame anyone you can" world, many people seem to forget about their own responsibilities. Any race car should undergo visual inspections of all welds regularly throughout a season.When I weld things for people, I look at what they are doing with the item and give a warranty accordingly. Tow truck drivers are the worst and I only give them 15 day warranties. Race cars get 30 days. If given the chance to inspect the car monthly and paid to make repairs as they come up, I would gladly give a continuing warranty for a whole season.When it all comes down to it, if it is your A$$ on the line, trust no one, see for yourself.Bill LambertArgon WeldingABQ NMSic gorgiamus allos subjectatos nunc
Reply:That clip was pretty rusty and not in good shape.  I don't have a WoO sprint rulebook in front of me but I do know that the WoO Late Model cage rule is minimum 1.5 x 0.095 which is pretty common in many forms of racing.  The clips typically don't have to be made from the same material so a designer will go as light as they can to save weight.  Teh wall thickness depends on the size of the tubing and the purpose for which it is used.  I think you'll mostly find mild steel and not molly on purpose built race car chassis designs though I understand sprinters use 4130 quite a bit.  NASCAR discourages the use of moly favoring something more malleable hence less prone to shattering on high impact.
Reply:Originally Posted by Grimm1 Proof that a good looking weld (it past visual inspection) isn't nesesarily a good weld.
Reply:All due respect to everyone's ability and expertise but the people that built the car aren't neophytes when it comes to sprint car design.  They can hold their own and a bit of everyone elses...    It's not a trophy truck.  It's not made to leave the ground.  Though this one did.  About 25' worth according the owner.  Use of thin tubing is a standard design on the clips of these cars.  And if they wad them up , they go get another one and sell what might be left to someone to replace the clip.  Which may have happened to this car, the guy that wadded it up can't tell if it's been clipped.  It reads to me like a guy took his first really big hit in a car that obviously had some corrosion issues.  And it broke apart.  Maxim sells 400 plus cars a year and if this were a reoccurring issue there would be more than one guy with a nearly five year old post complaining about it.Dave
Reply:This guy has been racing sprints and midgets since the mid 70's. Most recently he runs with the ASCS Patriots and the ESS, both 360 sprint organizations. While Sprint car chassis are not made to leave the ground, it is very common that they do. Looking closer at the pictures, I see the rust ArgonWelding pointed out which I could see weakening the joints. Both sets of rules, ESS and ASCS, only really specify that they be "sprint car frames". The cars are generally just bought from the same manufacturers as the Outlaws.Last edited by JeffB; 12-27-2009 at 10:26 AM.
Reply:Originally Posted by dstevensAll due respect to everyone's ability and expertise but the people that built the car aren't neophytes when it comes to sprint car design.  They can hold their own and a bit of everyone elses...    It's not a trophy truck.  It's not made to leave the ground.  Though this one did.  About 25' worth according the owner.  Use of thin tubing is a standard design on the clips of these cars.  And if they wad them up , they go get another one and sell what might be left to someone to replace the clip.  Which may have happened to this car, the guy that wadded it up can't tell if it's been clipped.  It reads to me like a guy took his first really big hit in a car that obviously had some corrosion issues.  And it broke apart.  Maxim sells 400 plus cars a year and if this were a reoccurring issue there would be more than one guy with a nearly five year old post complaining about it.Dave
Reply:Originally Posted by ZTFab. The welding was about the last thing to blame.
Reply:I would have to agree with ZTFab on the design. With thinner material used for weight reduction you would think the joint would be reinforced. The separation at the weld joint appears to be GMA and lacks penetration. I do not see any reason to diss the Maxim company they are following the specifications and design from engineers and if it only requires a VT inspection that's it. Not sure about the rules for sprint race cars but I would personally buy new and nothing that has been sitting for two years. If my body is going to be in this I would think about more inspections and actually modifying the joints if I could.Weldor/ Certified Inspector
Reply:Originally Posted by Grimm1If the break was break was in the Heat Affected Zone, then the weld is to blame even if the weld bead it's self held. Same if the break was allong any under cut. A weldor is responsible for anything his weld may affect, be it the H.A.Z., stress from distortion, undercut, to much heat on nearby non metal parts in some cases. You have to pay attention to more than just the puddle.
Reply:Just to throw my opinion in the mix for what it's worth.  i agree that a few of these look like they were crack for a while.   i do wonder if it is a 4130 chassis that the welds weren't normalized after welding. Nope they are not the best looking welds I ever seen. Another opinion of mine 4130 chassis are not necessary made to be stronger, the made to be lighter. Tubing is usually thinner than with mild steel to make it lighter. While 4130 is stronger than MS it's just about as flexiable, thus a 4130 chassis flexs more and should be considered a time lifed item. Had the racer been the original buyer of the chassis Maxim might be more concerned. Product suport on old second race car parts is seldom very good.Tough as nails and damn near as smart
Reply:I wonder if those would have even passed a sledge hammer testLast edited by tx-pipeliner; 12-27-2009 at 06:22 PM.
Reply:Sorry ZTFab. I've worked with weldors befor that didn't take the HAZ into account for the material they were working on. They over heated the HAZ, parts started splitting and they tried blaming it on the material. Then the customer had a metalurgist test it. It was splitting (outside of the weld bead) because the HAZ was messing up the base material. Once the weldors started using proper settings the problem was solved.So it leaves the question. Did this chassis break because the material was crap, because the weldor didn't respect the effect of the HAZ, or was it just poor maintenance? After looking the pictures over again, and the fact that some of the breaks were right on the weld, I'm leaning towards a combo of at least poor maintenance, and bad weld procedure. Though the choice of materials didn't really help either.