how do these welds look? Options

[babubabu]

please comment.

http://ghettoracer.com/files/welding-sample-1.jpg

http://ghettoracer.com/files/welding-sample-2.jpg

http://ghettoracer.com/files/welding-sample-3.jpg

thanks.

[Technic Al]

Is it an exhaust system
Stainless
Tig without a filler wire

I always find it difficult from a photo because there are no landmarks to judge sizes.

If it is what I think it is, ie an exhaust, it looks nice but will it be strong ?. I prefer to see reinforcement so that the weld is convex rather than concave. I think the tube to flange wont last long in service, the heat and vibration will see to it.

Hope i'm heading in the right direction, if not, can you post some details.

[babubabu]

[bobthewelder]

Hello babubabu!...how are you?.....Me thinks this is a 4/8 cylinder jobby? The TIG welds look like you are on the right track but there are a few ways to improve them: 1st JPG looks like a 2 into 1 collector (assuming) "looks like you are using a pulse?? if so then the speed is to slow and weld is too cold! bump up the amps a bit (huge assumption that the gauge is around 1.2 poss 1.6mm) and increase the pulse rate and you will get rid of the shrinkage "pips" that you can see on every single tack( for want of a better word) I know that you are purging because i can see how well your gas cover is on the tight part......this will definately improve things, also mate try not to be so brutal with the tacking up of the collector it seems to be quite hot at the swagged end! and make sure to keep the purge behind this area as well.(I know it has to be bashed around to make it round but any lack of fusion here will result in failure under load.) 2nd JPG looks like the primaries to collector lap fillet joint....All you need to do is increase the amps because the welds are to cold again..dont worry about excess penatration! you can always turn up the pressure of your backing gas, this will allow you to put down a flatter fillet without the danger of restricting exhaust gas flow with excess pen from your weld..
3rd JPG is your primary flange joint fillet and again it looks to cold: When you weld these you will find that your tack up should be as tight as possible on the face. When the joint has been tapped in tight, weld the outside face complete (fuse it in without filler nice and neatly with enough heat to allow the weld to be flat...your flange will be at least 5mm thick (I hope) so there is no danger of any stray penatration falling in.....then weld the fillet with a backing purge, same rules apply with bumping the gas back pressure to avoid excess penatration. You must play around with the pulse until your settings are just right and you will love the results.....Goog luck BTW.. /'-)

[tonyp]

"Fish Scale" never heard pulse welding called that before, if thats what its is. But it does look like filler is used but at too big an interval on drawing 2, plus there is a stop start on the far pipe which doesn't look very good but there is no stress on an exhaust so this would be no problem, the 3rd one is a good weld but would look better with filler wire.

[Backpurge]

Hi Babubabu
Agree with most of the guys comments above, it looks as if either the pulse frequency is too slow or the travel speed is too high, the overlaps should be a lot closer together and the welds would definitely benefit from a bit more reinforcement.

Cheers Bob

[Technic Al]

[rottenroot]

It's an exhaust, not a swiss watch !!!
Fit for purpose.....don't agree guys ??
The welding isn't fantastic but seen a lot worse + the companies producing these hang their hat on the "Guaranteed for life banner". If it falls off / fractures, etc you go back to where it came and get a new shiney one ;o)

what a laaarrffff
rgds

[Technic Al]

[babubabu]

thanks everyone for the feedbacks. i really appreciate you taking the time. the flange for this piece is just mildsteel since it is a final prototype for fitment check. in production run we are using stainless 304 lostwax casted flanges.

typically the next grade use for stainless seems to be 321. i haven't read/heard much about use of 410 in usa/asia. is that commonly used in uk?

this header is for naturally aspirated engines so exhaust temp won't be all that high.

[roger rough cap]

can't really give a comment on the welding but the photo's look nice

[boilerman]

i don't know if engloid comes to this site ....but this is the addy of his site with pics of proper welds....enjoy
http://mywebpages.comcast.net/engloid/workpics/workpics.html

[Halfloaf]

is that a d16 flange?

[Engloid]

As an American Welding Society, Certified Welding Inspector....

I'd reject every weld there.

The dimple in the middle of each spot is called a "fisheye." It is actually a microscopic hole that can protrude all the way through the weld.

If they want to weld in a method like this, they should overlap each spot such that this hole is remelted by the next pulse, and therefore eleminated.

Bu pulsing like this, they are letting the part get very cool between pulses, and keeping the overall heat affected zone smaller...but they are sacrificing strength and penetration.

Keep in mind that they do these overseas for a reason....cause they're CHEAP!! They save a lot of money by not using filler metal. This money alone is likely enough to by far cover the cost of backing their warranty on the parts that fail...and that's if they even come through with the goods when the part fails.

[gecko4]

mig over man its going under your car haha

[squirmy rooter]

engloid here here spot on mate

[smoke232323]

the man that said use 410 grade is spot on its high temprature steel and will sertainly cope with the expansion better plus a bit if filler wouldn't hurt

[Engloid]

I'll add more to this about filler metals...

Typically, anywhere that a weldment will see physical stress, including heat, filler metal should be used.

the reason is that metal is a compound that consists of many things. When you weld, everybody knows that certain gasses, metals, and vapors are released into the air. Also, some elements will tend to rise to the surface. Either of these reduces the amount of that element in the metal after the weld. Filler metals are typically made such that they have higher percentages of these elements that will be released into the air or will rise to the surface. By not using filler metal, your weld can be weaker than the base material.

In some industries like food process or pharmaceutical piping. filler metal may not be used.. but remember that this is usually thin tube that only has to hold itself up in the air.