• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

Can you weld "too" hot?

RobVG

Senior Member
Joined
Jun 20, 2009
Messages
1,028
Location
Seattle WA
Occupation
17 excavators and a stewpot of other stuff
I recently had a weld fail, which never happens to me :)

I don't think I got enough penetration. If your not undercutting and the bead shape is good, does it hurt to turn it up? Talking 3/8.
 

Jonas302

Senior Member
Joined
Jan 4, 2015
Messages
1,197
Location
mn
Sometimes welds fail because they were never engineered to hold the forces that are applied other times its just bad weld:)
 

FSERVICE

Senior Member
Joined
Apr 2, 2009
Messages
635
Location
indiana
did the weld break or the metal next to the weld? what material was you welding? what rods/wire? really need a little more info before anyone can give a good informed answer tho,,
 

Catpower

Well-Known Member
Joined
Sep 22, 2006
Messages
52
Location
Prince George BC
Occupation
Electrician, equipment operator
3/8" rod is huge! Generally you will want your decimal equivalent as in 0.375 or 375 amps. Some machines weld hot/ cold. When I was at one job you could tell about 15 minutes before breaks you would have to turn your settings down.The best I have done is 5/32" 7018. They say that you will get Carbon migration to the sides of your puddle. I have only had two welds crack one was the wrong rod needed 11018 worked beautifully. The other didn't have much weld on the old chain and the other link is still holding, 30 years later.
 

Dualie

Senior Member
Joined
Feb 23, 2007
Messages
1,371
Location
Nor Cal
Yes, to high an interpass temperature can weaken the metal in the Heat affected zone next to the weld. Then when the weld pool cools it can induce cracking next to the weld.
 

dixon700

Well-Known Member
Joined
May 11, 2014
Messages
210
Location
pa
Occupation
heavy truck mechanic
3/8" rod is huge! Generally you will want your decimal equivalent as in 0.375 or 375 amps. Some machines weld hot/ cold. When I was at one job you could tell about 15 minutes before breaks you would have to turn your settings down.The best I have done is 5/32" 7018. They say that you will get Carbon migration to the sides of your puddle. I have only had two welds crack one was the wrong rod needed 11018 worked beautifully. The other didn't have much weld on the old chain and the other link is still holding, 30 years later.

I believe he was talking about 3/8"material not rods..
 

RobVG

Senior Member
Joined
Jun 20, 2009
Messages
1,028
Location
Seattle WA
Occupation
17 excavators and a stewpot of other stuff
Mig welding. .045 co2 flux core.

Mild steel, grade 80, T-1, AR400. 1/8 up to 1".

I haven't been able to find a good voltage/material thickness chart, just used trial and error over the years. I've been playing around with lower voltages recently, guess I got my answer.

The piece was a KW s-cam bracket which holds the springbrake can. I've welded 3 over the years and they're still holding. I replace the ones on the steer axles.

I was just wondering if there are some general changes in weld properties at different voltages, penetration being one.

PS, the break happened at the edge of the weld.
 
Last edited:

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
Get the recommended settings for the wire you're using, usually available off the web from the wire manufacturer. Usually a pretty narrow range on voltage for a given wire size. I generally use a mix like 75/25 rather than straight Co2, you get a more fluid puddle and slower cooling. My typical error is trying to go too wide in a single pass which lessens penetration in the root of the weld. I'm currently running Lincoln Ultracore 71A85 and love it.
 
Top