Cooling welded connection

[Willl]

Well then, I guess that's the final word!

I'm guessing not,,,,

Oops, see, i proved myself.

 

[Gary Fowler]

Well I just have to throw my $.02 in here also. Having welded a substantial amount of pressure piping and taken numerous pipe welding test where the test straps(2" wide sections cut from the welder test coupon) were dropped directly into a bucket of water and then bent into a 180 after cooling to room temperature, I have never had a failure of the weld. Quenching like dumping into a bucket of water does not make mild steel welds subject to brittle fracture. I have actually seen fellow welders straps break when he slow cooled them when mine bent perfectly. I dont know if it was the welding or what, be both looked visually the same and same rods, same everything else except the quenching. Tempering where you dunk them and take them out several times will make them harder and possibly break rather than bend.
Cast iron needs a postweld heat treatment to relieve the internal stresses. When I welded them, I would use a rosebud to bring the whole piece up to about 1000 F and then wrap it in insulation till it was cool. Cast steel, I just let air cool.
So I would say that if your weld is sound and no trapped slag, porosity cold lap or lack of fusion between passes, etc. no matter what you did to cool it, it will most likely hold. A bad weld is likely to break regardless of cooling technique used.

 

[bobodu]

I never do it unless it is an ornament or something equally useless (ie."non-critical") Quenching only serves to make a locally tempered area around the weld and within the weld itself and this can be very brittle.
As far as cherry or black heat....I sometimes temper knife blades with just the residual heat from the anvil.

 

[Bennet.man]

I don't know too terribly much about metals, but I would have to agree with Gary. The low carbon content in mild-steel will not have the ill effects from quenching like a high-carbon steel such as cast iron, or knife blades. I have had coupons cut from weld tests using .045 flux-core wire welding, and have always quenched them between weld passes. As long as you have all of the slag cleaned out, and no porosity you shouldn't have any issues (given the assumption that you have a good weld to start with )

 

[sandman2234]

I am not as good of a welder as a lot of folks on this forum, but I did work for 15 years in a plant that made hi tensile steel wire/cable. For 5 of those years, one of my jobs was to test a weld from every operator on shift, every day. Since we had the machine to do it, one of the local testing labs would bring their weld test samples in for us to test. I have watched a lot of guys cooling welds in different ways, but one thing was for sure. Cool the weld too fast and it is going to break prematurely. Maybe not behind a 12 to 30 hp tractor, but it will break sooner than it would have if proper procedures had been followed.
Why would you want to take the chance that it "MIGHT" break if you cool it too rapidly? Are any of us in so big a hurry that we can't do the job correctly?
The best way to test a weld is to run it thru a wire drawing machine. If it isn't done right, I guaruntee it will break when it is being stretched to 30% of it's original size by being pulled thru a tapered die.
David from jax

 

[towmotor]

I've never had a problem arise by doing that, but the truth is that like many people who build things with steel for their own use, I know that the steel/weld will never be "put to the test" in terms of ultimate strength.
If I were welding for someone else (and I have), or working with high carbon/high yield steel, then I would never cool welds or flame cut pieces in water.

 

[weedpharma]

As a rank beginner backyard welder, I often use a handsprayer to cool my welds. This appears to be a compromise between no cooling and drown in a water bucket. No sudden temperature changes just quicker cooling.

Weedpharma

 

[greasemonkeyok]

I'm not an expert welder, and I don't play one on TV. But, 50 years ago a blacksmith taught me to quench cherry red steel in a bucket of water to "take all the temper out." Then you start the process of putting the temper back in the steel by heating in the forge and cooling slowly. Carbon content has big impact on how quenching will affect the molecular structure.

Brittleness is not the only bad thing that can come from quenching. If cooled too rapidly, the weld can develop internal stresses that will cause it to rust more rapidly than the surrounding area. If you stretch a barbed wire fence too tightly, it will rust much faster than the wire stretched straight, but with no tension.

 

[bobodu]

taught me to quench cherry red steel in a bucket of water to "take all the temper out."

That would make the inside soft but the outside would now be hard, but that depends on how long it is submerged. A quick dip wouldn't be bad because the internal heat would migrate outward.
Rapid cooling does not anneal.

 

[rhett]

already said, most projects are not that critical. slow cooling should be allowed for high stress and load points.

example: underwater welding is very limited these days, reason is the weld puddle quenches rapidly causing the weld joint to loose its ductility. another factor is hydrogen contamination which multiplys problems. habitat welding is the prefered method, wet welds are temp patches.

sure i do it, but it does reduce weld quality. components subject to vibration also should cool on their own.

had to add two cents