- Thread starter moggywelder
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Missed that too. By definition the HAZ* isn't melted during welding, i can't see how mechanical properties can be affected by filler wire chemistry. The PMZ (partially melted zone) which is a narrow region between the fusion zone and the HAZ can be affected by filler chemistry, I posted a link to an AWS study on liquation cracking with AlSi casting alloys back on pg1. Here's another one on the wrought alloy 2219 https://app.aws.org/wj/supplement/WJ_2000_05_s113.pdf
As said the thread is just going round in circles now (need a smiley for beating a dead horse)... physically repairing a wheel is easy enough if the welder knows what they're doing and there's nothing magic or special about the joint prep for repairing a crack just because it's a wheel.
The flavours of filler wire have been covered multiple times and the findings of that MSc thesis agree with what the AWS or Alcotec and various other sources (including me FWIW) have to say. Some people claiming to be 'specialists' disagree but when asked why it falls to pieces, they can't explain why in any meaningful way and we end up with a debate going round in circles like this one is.
The thesis and many people with a vested/financial interest in repairing wheels disagree with just about every other trustworthy source about basic aluminium metallurgy and the effects of heat treatment but often are unable to explain why [/beating a dead horse again]. If a single student thesis found something that's been missed by the rest of the world and cast Al wheels aren't affected by welding then it comes down to the skill of the welder to produce a sound weld free of gross porosity/LOF/inclusions etc. If repaired wheels usually fail through the weld and the thesis is right then, as i see it, a lot of wheel painters simply need to learn how to weld properly. Most welders that can consistantly produce high quality welds on a variety of materials can 1) usually find far more varied/interesting and better paid work than as an employee that spends all day sticking car wheels back together and 2) have gotten to that standard by working in environments where NDT, weld procedures etc are in place and as a result usually understand that there's a lot more to welding than physically fusing bits of metal together [/gross generalisation]
That thesis only looked at a couple of flavours of cast wheel, no mention of flow formed wheels and the 5454 wrought wheel they tested is very different to a 6xxx-T6 forged example. This link dated from 2011 i posted yesterday discusses a wider range of production techniques & Al alloys used (including modified/proprietary flavours)... basically loads of stuff that the thesis didn't investigate http://www.european-aluminium.eu/wp...-Applications-Chassis-Suspension-3-Wheels.pdf Still doesn't cover everything though, no mention of AlSi10Cu which is a flavour used by one of the large and well respected wheel manufacturers OZ Racing who supply several OEMs as well as producing wheels under their own name and for other aftermarket brands. Google OZ racing AlSi10Cu and you'll get a bunch of hits including a pdf about the production of their wheels and a list of the alloys used including AlSi7MgTiSr LP T6 which is different (better mechanical properties) to the AlSi7Mg talked about in the thesis. In short even if that thesis was 100% spot on when it was written it wouldn't apply to some (many?) of the wheels made in the last 10 or 15 years. EN46100 (LM2) is the nearest 'generic' alloy i can find to AlSi10Cu and is classed as non weldable due to it's copper content, more on the weldability of Al castings here http://www.slideshare.net/NFTN/the-weldign-of-aluminium-castings-october-2011
* most of it at least, some sources divide the HAZ into sections including the PMZ
As said the thread is just going round in circles now (need a smiley for beating a dead horse)... physically repairing a wheel is easy enough if the welder knows what they're doing and there's nothing magic or special about the joint prep for repairing a crack just because it's a wheel.
The flavours of filler wire have been covered multiple times and the findings of that MSc thesis agree with what the AWS or Alcotec and various other sources (including me FWIW) have to say. Some people claiming to be 'specialists' disagree but when asked why it falls to pieces, they can't explain why in any meaningful way and we end up with a debate going round in circles like this one is.
The thesis and many people with a vested/financial interest in repairing wheels disagree with just about every other trustworthy source about basic aluminium metallurgy and the effects of heat treatment but often are unable to explain why [/beating a dead horse again]. If a single student thesis found something that's been missed by the rest of the world and cast Al wheels aren't affected by welding then it comes down to the skill of the welder to produce a sound weld free of gross porosity/LOF/inclusions etc. If repaired wheels usually fail through the weld and the thesis is right then, as i see it, a lot of wheel painters simply need to learn how to weld properly. Most welders that can consistantly produce high quality welds on a variety of materials can 1) usually find far more varied/interesting and better paid work than as an employee that spends all day sticking car wheels back together and 2) have gotten to that standard by working in environments where NDT, weld procedures etc are in place and as a result usually understand that there's a lot more to welding than physically fusing bits of metal together [/gross generalisation]
That thesis only looked at a couple of flavours of cast wheel, no mention of flow formed wheels and the 5454 wrought wheel they tested is very different to a 6xxx-T6 forged example. This link dated from 2011 i posted yesterday discusses a wider range of production techniques & Al alloys used (including modified/proprietary flavours)... basically loads of stuff that the thesis didn't investigate http://www.european-aluminium.eu/wp...-Applications-Chassis-Suspension-3-Wheels.pdf Still doesn't cover everything though, no mention of AlSi10Cu which is a flavour used by one of the large and well respected wheel manufacturers OZ Racing who supply several OEMs as well as producing wheels under their own name and for other aftermarket brands. Google OZ racing AlSi10Cu and you'll get a bunch of hits including a pdf about the production of their wheels and a list of the alloys used including AlSi7MgTiSr LP T6 which is different (better mechanical properties) to the AlSi7Mg talked about in the thesis. In short even if that thesis was 100% spot on when it was written it wouldn't apply to some (many?) of the wheels made in the last 10 or 15 years. EN46100 (LM2) is the nearest 'generic' alloy i can find to AlSi10Cu and is classed as non weldable due to it's copper content, more on the weldability of Al castings here http://www.slideshare.net/NFTN/the-weldign-of-aluminium-castings-october-2011
* most of it at least, some sources divide the HAZ into sections including the PMZ
normspanners
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I have repaired straightened many a ally wheel, the old minilites would stand a lot of abuse and have had the same straightened wheels when they have suffered a puncture and done two or three mls on a flat in the forest, have still had another tyre fitted and done a turn, but they where quality wheels to begin with.
I used to heat them,with a heating rose, rub soap on when that went black you could knock them back into shape, let them cool and they would be fine.
The old minilites where a magnesium alloy.
I used to heat them,with a heating rose, rub soap on when that went black you could knock them back into shape, let them cool and they would be fine.
The old minilites where a magnesium alloy.
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Chris deleted his own post for some reason, it wasn't removed by one of us.
doubleboost
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I had a set on My Cooper S lol happy days
C
Chris Stevens
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I have been repairing alloy wheels as a sideline for about 15 years now, most recently for one of the biggest refurbishment franchises in the country. Never had any sort of real problems with this, and few if any returns.
Interestingly it seems to me that today, first hand experience of actually doing something appears to count for very little, and there is an awful lot of reliance on text book technical data, rather than actual experience.
Not sure whether this is that great an idea, as should all motorists choose to believe wheel repair is either problematic or unsafe, then I would guess the current £730 million per year spent in the area of vehicle damage related to pothole impacts, would increase substantially, and make motoring even more costly?
This is my last post on the subject of wheel repair, as I have no wish to contradict the technical reasons posted which suggest wheel repair is unsafe, which I am sure are perfectly valid and worthy of serious consideration.
Interestingly it seems to me that today, first hand experience of actually doing something appears to count for very little, and there is an awful lot of reliance on text book technical data, rather than actual experience.
Not sure whether this is that great an idea, as should all motorists choose to believe wheel repair is either problematic or unsafe, then I would guess the current £730 million per year spent in the area of vehicle damage related to pothole impacts, would increase substantially, and make motoring even more costly?
This is my last post on the subject of wheel repair, as I have no wish to contradict the technical reasons posted which suggest wheel repair is unsafe, which I am sure are perfectly valid and worthy of serious consideration.
daleyd
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Things like these.....What are O&G exotic valves?
That's a valve body for an undersea wellhead about to go in a furnace for heat treatment. Some fancy welding (buttering?) goes on inside the hole you can see, which I won't even pretend to know anything about!
Richard.
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Sorry to keep dragging this out but quick Q. Would the higher Si content in a 4047 help further with regard to liquidation/cold cracking. I've no intentions of welding one but I do love a bit metallurgical info.
Heading into areas of metallurgy that make my head hurt but AIUI, yes but sometimes at the expense of other properties. If i was welding an AlSi7whatever casting i'd reach for 4043 wire. If i was welding bits of a wrought alloy to it i might reach for 4047 as the weldpool will freeze at a slightly lower temp/over a wider temp range* and (very crudely) with everything remaining 'mushy' for a bit longer it's more likely to be able to resist the shrinkage stresses and microscopic liquation cracks are less likely to occur/more likely to be backfilled/healed by the remaining liquid portion of the solidifying weld. Kinda a similar deal to solidification cracking but less severe/obvious
In the real world the composition of the casting is usually guessed and on a probability basis 4043 is usually the first choice
* 4047 has a narrow freezing range but obviously is dilulted by the parent material changing things some
ETA, the buttering of the valves is probably an inconel overlay? Cheaper than making the entire thing from the stuff
Maker
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Is the oil/gas very hot or does inconel have other desirable properties for exotic valves?
Are they named that because they're made of exotic materials?
Richard.
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do I have this right.
the lower solidification temp over a longer period of time meaning the 12% Si filler stays elastic and cools at a slower rate. Which I guess yes better for solidification cracking. I would guess though the trade of is mechanicals.
Richard.
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Inconel is very corrosion resistant also at high temperatures.
Richard.
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Inconel although a lot of people think high perfomance GP exhaust is more commonly used in cladding. It's not particularly hard or tough but it's very high nickel content make it a super corrosion resistant material. Boiler tubes take a good lump of the stuff regularly along with gas/oil, chemical ind etc. as HR said you find these items are clad in it rather than made out of it. It's seriously pricey gear. A 15kg spool can be knocking on the door of £500.
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By spool, are you implying it can be mig welded or is it used in a CWF on a tig welder (Or SAW)? I would have thought this kind of material would only be tigged.
Yeah. Eutectic alloys like 4047 typically shrink less as they solidify too although in a weld obviously dilution effects things some. The classic example is a 6xxx series where various 4xxx or 5xxx series fillers can be used to dilute the magnesium silicide that makes the parent material more prone to solidification cracking and of the usual suspects 4043 is more forgiving to use but both weaker and less ductile than 5356. The AlSiMg casting alloys are fairly similar to 6xxx series with the obvious exception of having a chunk more Si in them so you don't really want to add more Mg leaving several 4xxx series wires of which 4043 is usually the best choice overall
What Runnach and Richard said. Corrosion resistance, especially at elevated temps is a big part of it. Not my area but as far as spools of the stuff goes don't forget TIG can be used with a seperate wire feed, automated hot wire TIG for example although i believe some of the fancy synergic MIGs are also used for cladding these days?
Richard.
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Yes it's used very heavily in mig form and one of very few that will run in mixed gas as well as pure argon. (It's nicer in pure)
I've not heard of it been used in subarc but it might be the case. I believe some producers are going about a flux cored inconel wire for joining out of positional work.
As above it's very nice to tig weld manually also.
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How does hot wire feed work?
