We make waste water pumps from welded commercial pipe fittings. Marketing is asking us to make them "prettier". We currently wire brush and passivate the welds. Electropolishing will be very expensive because of the sizes. Ø 8-12" Dia pipe fitting assemblies can weigh over 1,000 lbs and be 4' feet high. Any suggestions?
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Finishing a 304 SS welded assembly
- Thread starter capntom62
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- #3
I am not sure if you are asking that question or making a statement.
The details of the assembly would prohibit that level of uniformity. Some details are cast, extruded or rolled and welded pipe. They just need to look professionally made to a non technical person.
The details of the assembly would prohibit that level of uniformity. Some details are cast, extruded or rolled and welded pipe. They just need to look professionally made to a non technical person.
btrueblood
Mechanical
Assuming the welds are structurally sound, what is marketings's beef? Heat tint? Spatter? Want to post a picture of a "bad looking" weld?
I'd avoid wire brushing, just because the usual steel wire can embed bits of wire into the stainless, and you would then fail a passivation test; hopefully you are using a stainless brush. Using an abrasive flap wheel and/or disc sander would be better. Grit blasting might be another alternative.
I'd avoid wire brushing, just because the usual steel wire can embed bits of wire into the stainless, and you would then fail a passivation test; hopefully you are using a stainless brush. Using an abrasive flap wheel and/or disc sander would be better. Grit blasting might be another alternative.
mfgenggear
Aerospace
Op
Look into glass bead peen or blast.
And optional to buff with portable
Using wheels and red rouge, hopefully I spelled it correctly.
Look into glass bead peen or blast.
And optional to buff with portable
Using wheels and red rouge, hopefully I spelled it correctly.
mfgenggear
Aerospace
Blast will remove all the scale, buffing while not necessary will make them pretty.
mfgenggear
Aerospace
Here's the deal gentlemen, manufacture parts can be not be pleasant to the eye but functional. And meet all the standards.
But when parts or assemblies are pleasant to look at. A fascinating act happens. Inspectors, and customers are
More pleased with the results.
On the type of work I do. I would have then bead blast after heat treat. To remove oxides and scales.
If temper etch and bake required and no plating I would require a very light bead blast and buff. To make them shiny.
Or a least pleasant to look at.
The customers upon receiving were very happy. Of course all was to specification , dimensional and on.
Just be mindful of close tolerances.
Some operators try to do to good of a job. And close tolerances will go out of spec.
But when parts or assemblies are pleasant to look at. A fascinating act happens. Inspectors, and customers are
More pleased with the results.
On the type of work I do. I would have then bead blast after heat treat. To remove oxides and scales.
If temper etch and bake required and no plating I would require a very light bead blast and buff. To make them shiny.
Or a least pleasant to look at.
The customers upon receiving were very happy. Of course all was to specification , dimensional and on.
Just be mindful of close tolerances.
Some operators try to do to good of a job. And close tolerances will go out of spec.
EdStainless
Materials
Either blast the whole thing with fine shot or brush finish the whole thing.
High purity piping has a '189' finish just so that it all looks the same.
And passivate after your finishing to remove trace metal that could lead to rust staining.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
High purity piping has a '189' finish just so that it all looks the same.
And passivate after your finishing to remove trace metal that could lead to rust staining.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
capntom62 said:
1) My post does not have the (?) symbol, so it is not a question.
2) The required surface finish must be performed on a sample plate prior to commencing manufacturing, approved by the customer. This sample plate is used for comparison with the production part.
Regards
Train the welders, so that they make more uniform (visualle pleasing) welds?
Use rotating devices, so the welds are made in 1G?
Change weld process (if only for the cap)?
Here's an example of one of our interventions (before/after).
Is it something similar you're looking for?
Use rotating devices, so the welds are made in 1G?
Change weld process (if only for the cap)?
Here's an example of one of our interventions (before/after).
Is it something similar you're looking for?
- Thread starter
- #13
We are leaning towards a portable buffing process. Lots of great responses, and some good questions. "What do they want?" As "mfgenggear" states, non technical people do not know what they are looking at and favor the prettier products. Blasting, electropolishing or coatings cost too much (in their eyes).
mfgenggear
Aerospace
OP
Bkasting is a very effective and efficient method of scale removal.
Did you try quoting to farm it out, or
Quote a large blasting cabinate.
Good air pressure is required.
Purchasing abrasive blast. It's very
Economical.
Bkasting is a very effective and efficient method of scale removal.
Did you try quoting to farm it out, or
Quote a large blasting cabinate.
Good air pressure is required.
Purchasing abrasive blast. It's very
Economical.
- Thread starter
- #15
The assemblies can be quite large, 4' foot cube and weigh 2,000 lbs. A cabinet would be large, with cranes or hoists to move parts around, ventilation system constraints, labor hours to blast. We had one blasted in our parking lot months ago and it took about 4 hrs. I have designed and built a few large ones in my aerospace career. Farming it out has cost, delivery issues and lead time. They want a "quick and cheap" solution. I HATE using that phrase, as I am sure we all do. There is no scale. It is 304 SS cast elbows, extruded or rolled / welded pipe and forged flanges.
EdStainless
Materials
We had a walk-in blasting room that used.
Sometimes we could fit one part and sometimes thousands.
There is no cheap way to get a uniform appearance.
It will take time and money.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
Sometimes we could fit one part and sometimes thousands.
There is no cheap way to get a uniform appearance.
It will take time and money.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
EdStainless
Materials
You need to figure out, do they want pretty welds or do they want the entire part to have a uniform look?
Two very different requirements.
Just remember to chemically passivate after any surface modifications.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
Two very different requirements.
Just remember to chemically passivate after any surface modifications.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
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