Thread: Welding on chasis

Originally Posted by justinc

As a general rule, NO welding is permitted on the web(Vertical plane) of any chassis, only the flange(Horizontal plane) UNLESS certain shapes are adhered to, IE staggered weld lines, NO sharp corners, and preferrably with the addition of a stiffener plate, plug welded. Under no circumstances are tempered chassis to be welded, (IE truck prime mover and some trailers)

I can't see a problem if all these are kept in mind, and your overhead stick welding skills are sound...

JC

The NSW guidelines are the opposite to this. You can weld on the sides of the chassis, but not the top and bottom plates. The top and bottom is where the forces pass through, with the sides maintaining the seperation between the two. If anybody other than the manufacturer welds the top and bottom plates then you should't be able to get it approved.

NSW RTA VSI06 Pg4
http://www.rta.nsw.gov.au/registrati...s_nov_2007.pdf

Interestingly though I dont think there is any reference to this in the VSB14 documents - but for cracking reasons I really would make a significant effort to not weld the top and bottom plates and keep everything on the sides.

Originally Posted by djam1

Justin Im sure you are right in saying this but if it were adhered to there wouldnt be any Prime Movers left in the Territory.
I know a bloke that made a living out of this sort of thing I have even seen him repair one of our Unimogs that we broke in halves lol

Its only a coupld of bits of box and a hangy off bracket, just stitch them on already

Originally Posted by Slunnie

The NSW guidelines are the opposite to this. You can weld on the sides of the chassis, but not the top and bottom plates. The top and bottom is where the forces pass through, with the sides maintaining the seperation between the two. If anybody other than the manufacturer welds the top and bottom plates then you should't be able to get it approved.

NSW RTA VSI06 Pg4
http://www.rta.nsw.gov.au/registrati...s_nov_2007.pdf

Interestingly though I dont think there is any reference to this in the VSB14 documents - but for cracking reasons I really would make a significant effort to not weld the top and bottom plates and keep everything on the sides.

Thanks Simon, I am now really worried about approaching senility, having just gone back and seen what I wrote!! Talk about not proof reading, you're right it should read the exact opposite

Maybe its approaching holiday time again.....

JC

Originally Posted by justinc

Thanks Simon, I am now really worried about approaching senility, having just gone back and seen what I wrote!! Talk about not proof reading, you're right it should read the exact opposite

Maybe its approaching holiday time again.....

JC

lol! I'm king of not proofing and think the same at the start of term!

Originally Posted by djam1

Justin Im sure you are right in saying this but if it were adhered to there wouldnt be any Prime Movers left in the Territory.
I know a bloke that made a living out of this sort of thing I have even seen him repair one of our Unimogs that we broke in halves lol

djam1,

I agree I have also seen it (and done it )before, but it isn't really good practice. I remember seeing a big DO NOT WELD sticker on a new truck chassis again the other day, but I wonder if that will stay there for long..

Also, done in a particular way it is quite strong and therefore reasonably safe, but I dare say the insurance company would have a field day if anything happened after such a repair job

JC

I wonder if they are heat treated to help prevent fatigue in the chassis... i guess once its cracked then it wouldn't be a problem in that spot any more.

Guy across the roads prime mover has just clocked over 2million km's! Kenworth... it still looks brand new to me!

Originally Posted by Chucaro

The weld undercut is a good indication of penetration. Oh well, that is what I have learned when I done my ticket with CIG back in the early 70's

Undercut does show the weld to have penetration, but insufficient deposition at the edges, resulting, as stated above, in reduced thickness of the parent material and thus a weak point. Say you have a 6mm plate that you are fillet welding, and you leave a .5mm undercut along the edge of the weld- your material is now only 5.5mm thick along the edge of the weld and that is where it will fail. Proper technique will give good penetration as well as proper deposition right across the weld. I don't much care when or where someone done their ticket, I would not welcome them introducing weak points into my chassis.

Originally Posted by POD

Undercut does show the weld to have penetration, but insufficient deposition at the edges, resulting, as stated above, in reduced thickness of the parent material and thus a weak point. Say you have a 6mm plate that you are fillet welding, and you leave a .5mm undercut along the edge of the weld- your material is now only 5.5mm thick along the edge of the weld and that is where it will fail. Proper technique will give good penetration as well as proper deposition right across the weld. I don't much care when or where someone done their ticket, I would not welcome them introducing weak points into my chassis.

If the first run have done in a way to produce the undercut and ensure satisfactory penetration the cover run is done to cover the undercut and blend the coats, therefore there is not reduced thickeness in the meterial.
Perhaps techniques have changed since 1973 but my work passed the necessary test back then and I never have a high pressure pipe leaking or an structural member fail..
It is your priviledge to believe that your knowledge is above the experts who teach welding and doing structural and high pressure welding every day. I go by what these experte have teach me