Stress Removal After Welding

More info! This is by no means anywhere close enough information to make a suggestion.

Drawings, materials, part description, stresses anything!

What is it?

Consider whether the item, or the weld, is large enough to withstand the stresses it encounters.

Send at least a few pictures before and after break down

your question suggests you selected the correct materials to begin with and the welds were quality ones....as well as suggesting the engineering and original design should have held up in the application they were used in......which is far too many assumptions for anyone to help you. reformulate your question with plenty more background information while you're warming up the X-ray machine

The life of the part is dependent on many things. Some of which are the material it's made of, the temper, forces applied, the material its wearing against abrasiveness.

Since none of that information is given.

The only suggestion I can recommend to increase the life. Is leave the part out. It won't wear at all or break.

Post weld heat treatment, and some classes on metalurgy and mechanical engineering!

Lately I've been using a single barrel Bourbon and some nice Jazz to relieve stress.

Hmmmmm. That would work.

They might consider pouring the bourbon directly on the hot weld.

Agreed.

That a component needed to be repaired in the first place suggests a loading underestimation from the onset.

If it was fit for purpose in the first place then it wouldn't need to be repaired.

It could just be too flimsy to be fixed...

Your answer is the most likely culprit and is a practical answer for an operator seeking knowledge. Good answer TCM, and thx. Honestly, I was down the road of materials and engineering, like most of the others, thinking we did not have enough info to be helpful.

I grew up around ours and friends farm equipment plus went on to doing regular repair work on construction and related heavy equipment so I have became very familiar with this sort or repeating cracking issues.

To me the symptoms are a very common thing that is almost always related to a part being underbuilt, over worked or having a less identifiable secondary defect in a related structural or supporting component.

If lack of proper or complete maintenance allows for metal fatigue and stress cracking to set into a part unfortunately all the welding and rewelding again and again in the world will not fix it.

One can weld many things: ferro and non- ferro metals, plastics, fibers. The only common spec. is that you change the molecular (and/or crystalline) structure with applying heat and foreign material(s).

Depending on the material(s) used other standards have to be used. This is called technology.

You have to check hardness of material where you want to perform repair work.

Material of construction decides the heat treatment and other welding process.

So please check MOC

Naman,

What exactly are you welding?

Someone else suggested a photo. It was a very good suggestion.

I agree with Anonymous, further imho you should check heat deformation and therefore if your part can stand the heat and the stresses.

You need a qualified weld procedure (WPS). That would give you the correct rod, preheat, inerpass temperature, and possibly the need for PWHT. Some materials are difficult to weld successfully. There are some free lance welding engineer that would for a price be glad to help you.

I have seen several weldment drawings that state "STRESS RELIEVE PER AWS D1.1/D1.1M (2004) OR LATER". Perhaps this procedure would help solve your problems.

I suggest that you send at least three of the failed parts off to a reputable testing laboratory and have them analyzed for cause of failure.

Once you get the results back you may want to hire a compenet metalurgist to decipher the test result and to investigate the process and identify the "root-cause" of the failure.

It may be that welding of the part(s) is causing them to be brittle and all you may need to do is anneal the welds with controlled heating equipment before placing the part(s) in service.

I'm not a welding engineer, so this is a guess. Does it break again at the SAME location, or beside the original break. Perhaps you need to heat it in an oven before welding, the let it cool slowly (couple of days!) after welding. I think shot peening will handle surface stresses. Is this part cast iron? I understand cast iron is terrible to weld. Are you using groove welding so the whole thickness is welded? Like others have said; more info needed.

The answer is here.

If you told us the type of material you were welding sooner you could have been on your way a long time ago. I Googled "en8 steel welding" and this was at the top of list. Google is a tool that you need to learn to use.

One often overlooked cause of stress is the heat generated from the continuous weld and its location causing stress. Some welds must be done so that the material expands/stress' the least amount possible. When the placement of adjacent welds is done in a continuous line the metal overheats and stresses are included into the material. One method of reducing this possibility is to do each subsequent weld in a different location on the weld line. Some are: alternate ends, alternate sides, run a weld a rod long and then go to another location, weld there, return adjacent to the first and weld. This is sort of a "leap frog" effect with changes in location and direction. A perfect example of this is to stick weld 2 pieces of flat stock together. start at one end and weld until you get to the other end. When done the flat stock will be curved to the face of the stock with the weld. Do this again but run one stick of weld on end "a". Next go to the opposite end "b" and run a stick of weld. Run a stick of weld in the center. Go back to end "a" and near the previous weld run another stick of weld. Continue doing this until the two flat stocks are welded together. This will be a continuous weld but will not be distorted as the other was due to the ability of the metal to dissipate the heat generated by the welding in alternate places. The first generated heat but was unable to dissipate it since there was welding being done next to it.

This is often used to prevent cracks or stress breakage in cast iron when welding with Ni (Nickel) rod. Cast iron is extremely sensitive to heat distortion while welding and often requires torch or oven preheating along with this method. NI rod is good but not perfect for this application.

Give this a thought.

Good Luck, Old Salt

After welding bury the welded part into some lime powder to completely cool down, this should solve what you are talking about.

This is one of the best and easiest technics for welding stress relief.

Lime powder...

err, how to do?

First of all, welding is not just welding, it is a science. Without knowing what the material is, you may require preheat as well a post heat. The only way to find this out is to know what your material is - what are the constituent elements and their percentages. Once you have established what you are going to be welding, you can find, online somewhere I am sure, a pre/post heat weld calculator(I'm old fashioned, I still use the manual wheel one).

Also, once you have found the material spec that you are welding, you will have to find out what kind of filler rod you should be using. Suggest you contact your local welding supply store for that as they are supposed to be the experts.