I do not know of any welding standards that accept vibratory stress relief in lieu of thermal stress relief. Having said that, there is no better proof than to qualify the WPS using the procedure proposed for use in production.
I have used it with a level of success on aluminum weldments in preparation for machining. It is easier to hold the required tolerances once the parts had been vibratory stress relieved.
I did not have the same level of success when using the system on high strength low alloy steel.
I have read about vibrating the weld during the welding process. The vibrations agitate the weld pool and "allow" to atoms to align more easily. I have no first hand experience with vibrating during welding. Maybe someone here has actually used the process and can provide some experienced based feedback.
Best regards -Al
I am not familiar with this process myself but I notice a couple of things in Al's reply that cause me to really wonder:
1) What materials are we talking about?
2) What process in being used?
3) What code is being invoked?
4) Are there any PQR's and/or WPS's being referenced that are in question as to applicability?
5) Are there requirements in the Job Specifications to utilize it?
6) Is the job already underway or just being bid and set up?
Have a Great Day, Brent
Al is right. Up to now, no American Code or Standard accept vibratory stress relief in lieu of thermal stress relief, which is the only one they accept. However, you can use vibratory stress relief for a "non code" application, of which there are many examples.
Back in 2004, me and a former pupil of mine at the Engineering School of Mackenzie Presbyterian University in Sao Paulo, Brazil, presented a paper before the Brazilian Welding Conference organized by the Brazilian Welding Association. In the paper, we made a comparison between both methods: thermal and vibratory.
You can download the paper for free and written in English at www.stressreliefengr.com/news.html
Same as you, I've never seen vibratory stress relief being performed during welding, always after the weld is complete. If I were you, I'd carry out a test following your customer instructions; in other words, I'd made a test weld while vibrating it and see what happens.
Giovanni S. Crisi
Sao Paulo - Brazil
Nice article.
I have a friend that did a research project for the company mentioned in the article. The purpose of the research was to determine what the vibratory stress relief did and how to predict the outcome. Their success at meeting the objective of the research was somewhat limited. The process works. It works good on some materials, but on other materials the benefit was not as pronounced. How or why it works was not conclusive.
As I noted, we used it with good success on aluminum weldments that need to be machined and tight tolerances maintained. The same could not be said for high strength steel. Some benefit resulted from the process, but it was not as pronounced as the results when stress relieving softer, more ductile, low strength materials.
I would like an opportunity to see the vibratory method applied to an in-process welding operation. I have heard good thing about the process, but I have no first hand experience with it. To endorse it or to condemn the process without actual experience would be short sighted.
Nothing ventured, nothing gained.
Best regards - Al
Thanks for all the input guys. I will be running these coupons in probably 3 weeks and we will see what happens!
Hey browland,
If the Customer wants to use vibration during welding, give him a quote with and without.
One of the other departments here are looking into the benefits of using this process (about a year ago). I'll try to dig up some info, but I think I remember the company that sells the equipment stated increased toughness due to reduced grain growth.
There shouldn't be any cracking with A36 & 304 (commonly welded). I think something fundamentally is wrong. Vibratory weld process may not address the root cause.
Tyrone
The company that sells the equipment is called Meta-Lax.
www.meta-lax.com
Here's a tidbit from their website:
In addition to stress relieving, the patented Meta-Lax vibrations can be used during welding to prevent distortion, cracking and weld defects, as well as for welding faster.
Tyrone