when i stretch trucks out i just use 70s-6. i overload my truck way to much. its an 08 dodge diesel running about 450hp. my trailer loaded with the backhoe puts my total truck weight at 41000. been using it over a year with no problems. havent had any customer complaints either. i did use a little pre heat
Whew, hope you have a cdl :P
I worked for an auto frame plant from '84-'91. During that time car frames We made had .05% carbon max. [that is very little carbon].
They were MIG welded with no pre or post heat treat at the factory. I don't know for sure what filler wire was used, My guess is 70S-3, shielding gas was CO2.
The only frames made from heat treatable material were for heavy trucks
Ummmm I am sure this post will draw some comments.........
We used 120-18 on double axle tractors and since I have used the same on lighter truck frames.......its not proper or approved but all the extended frames I have built are still on the road since 1994 (i think).....all welding and mods were done behind the spring hangers. Carefull prep and thoughtfull design but all said and done it was 120-18 tying it all together.
Heavy truck frames from Dana were made from 1027M and heat treated. They were tougher than woodpecker lips after heat treatment. You could drill holes in them with cobalt bits, but they were tough. These would have required specific weld procedures and high strength filler.
Car, light truck & medium duty truck frames are redily welded with no special precautions or materials, however proper engineering of the welded joint is always mandatory. 70 KSI filler would be a pretty good match to the parent metal.
to my knowledge auto car frames were never made out of high carbon steel, do to the associated manufacturing difficulties and costs, cheaper just to use a lower grade of material and use more, than try to jump thru the hoops of machining and welding high carbon steel. (with the exception of a few engine components).
Anyways the vast majority were made out of low carbon steels and MIG welded or resistance spot welded with no heat treatment.
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