Re-sulphurized or 'free-machining' steels would create exactly the centerline crackig behavior and porosity that you're seeing.
Knowing nothing else, this is where I'd bet that your problem lies.
David Benson
Benson's Mobile Welding & Fabrication
www.bensonmobilewelding.com
We could use some more information on the weldment in order to recommend corrective measures.
What is the thickness of the tube and plate?
What welding process, machine, filler metal, shielding gas(if any), and parameters(volts/amps/wire feed speed), pre-heat(if any)?
What is the position or...
Clparks,
I operate a small, currently part-time, business. I'm a one-man operation. I handle equipment repair and small fabrication work. I tend to shy away from actually designing anything. I require the customer to assume liability for any new fabrication, and I really prefer that they...
With an interference fit you can bet that at least some of the manganese phosphate is removed during assembly. In my experience iron and manganese phosphates are good for preventing rust in storage, and as a carrier for a rust preventative oil, or as a base for paint. But for long term...
Steve2007,
Are the repairs cracking, or are the repairs holding and cracks occuring elsewhere on the part?
Finding the root cause may(likely will) suggest refinements that could be made to the repair procedure. Finish your RCA and provide your findings along with a photo of the failure...
Mechanical design calcs aren't my strong suit. But, did you consider that the shear strength in the HAZ of the base metal will be closer to that of the 6061-O material; about 12KSI? This is about half the shear strength shown on your calc sheet...
What's the bevel angle and what process are...
Not enough information to even attempt answering the question.
What's the base material? Welding process parameters?
Just for starters...
David Benson
Benson's Mobile Welding & Fabrication
www.bensonmobilewelding.com
Bestwrench,
The prevailing opinions seem to be that most of the spots are polishing artifacts. While some of them may well be, I'll stay with my suggestion that there are several varieties of carbides visible. The nominal chemistry you mentioned is typical of tool steels. Ignoring the water...
Bestwrench,
I don't think the spots are artifacts of the sample polishing. And they're not water spots, which was the first thing that popped into my mind after reading your post, but before I looked at the attachement.
They look like some kind of inclusion or structure in the steel. The...
There are coatings that a good heat treatment shop can apply to a part to block the carburization process. Conceivably, you could shield the areas to be welded with one of these coatings, case harden the parts, and then weld them together afterwards.
Without knowing anything more about the...
A couple thoughts.
I've seen joints such as you describe in the field. I don't know if your end use application is the same as what I've seen....
I would not count on getting a full penetration weld with the joint configuration you sketched out. Even with the radius of the rod allowing...
I've worked with both MSI Labs, in Dayton, OH.
Metallurgical Services, Inc.
http://www.millerconsolidated.com/met-lab/index.html
Metallurgical Solutions, Inc.
http://www.msilab.com/index.htm
The first is a larger, "corporate" lab.
The second is a smaller, but fully equipped operation...
Ah,
How large are the weldments? What is the joint geometry? What process is being used to make the welds(GTAW, SMAW, GMAW, FCAW-G?)
How many welders are working simultaneously?(if this is a large vessel)
Need to know many more details before anyone can formulate an answer to your question...
I've set up X-ray spectrometers in several steel mills over the years. (I used to work for Philips) The mills I worked with used Wavelength Dispersive X-ray Fluorescence Spectrometry (WD-XRF) or Optical Emmission Spectrometry (OES) for quality control. Elements lighter than Na are handled by...
Check this article:
http://www.cartech.com/techarticles.aspx?id=1450
"Ralph’s is usually best for the precipitation hardenable stainless steels; however, Vilella’s reagent will work fine if a light etch is preferred. Etching time will vary because the alloy in the aged condition will react...
A fishing hook from 3/4" stainless rod?! Dare I ask what you're trying to catch? Killer whales? It's not April 1st, so I'll assume this isn't a spoof.
Anyway, 304 is an austenitic stainless steel, so it shouldn't lose any strength from the heating. Bending it could would work harden it, and...
In my experience, sensitization of stainless steels is a function of time/temperature and carbon content. If your ss304 cladding is a low carbon grade, and or sufficiently alloyed with Titanium and/or Niobium, then sensitization problems should be minimal.
304 is fairly high in Chromium, so...
Couple thoughts,
I agree with israelkk in that the hardness for these precipitation hardened stainless steels can vary widely. Having worked with 17-4PH in the past, my experience has been that the final properties can vary greatly, depending on the processing methods.
For example, if...
Mr168,
I understand and sympathize with the 'political' issues you face in dealing with your heat treater. I've been in similar circumstances myself (I think).
So, sounds like power supplies and filler metal are not a part of the problem.
I'm curious now about this sand blasting you...
