Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
(OP)
Hi...
Good to see you all once again,
I have a query on vessel fabrication.
1. We are fabricating a stainless steel vessel in our shop. During the fabrication time our shop people separating all carbon steel plates near by the SS Vessel during the welding time. is it really effect the CS material...?
Is there any particular reason behind it.
2. If above is true, Why the SS vessel external attachments are directly welding with CS material.
3. Can we directly weld stainless steel and carbon steel. is there any corrosion reason behind it.
Please clarify the above 3 statements
.
Thanks in advance,
Ramesh Kumar

Good to see you all once again,
I have a query on vessel fabrication.
1. We are fabricating a stainless steel vessel in our shop. During the fabrication time our shop people separating all carbon steel plates near by the SS Vessel during the welding time. is it really effect the CS material...?

Is there any particular reason behind it.
2. If above is true, Why the SS vessel external attachments are directly welding with CS material.

3. Can we directly weld stainless steel and carbon steel. is there any corrosion reason behind it.

Please clarify the above 3 statements
.Thanks in advance,
Ramesh Kumar





RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
The grinding residue/dust from manufacture of CS components in the proximity of SS components would contaminate the surfaces of the SS components causing localized break down of the oxide layer. When I worked for a factory which manufactured both CS and SS vessels, there were dedicated areas cordoned off for SS vessel manufacturing. Strict rules were in place which prohibited even stepping-/walking on unprotected SS plates for the risk of boots/shoes contaminated with dust from the CS section or contaminated with oils/greases.
One of the first steps in manufacturing SS vessels in our factory was to "wrap" st/st plates with a protective film which was only removed prior to delivery of the completed vessel.
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
Ref your questions 2 & 3, it can be done but it is a poor practice. Best practice is to weld CS attachments to SS pads.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
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P.E. Metallurgy, Plymouth Tube
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
Regards
r6155
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
Separation must be done to avoid contamination of the stainless steel with carbon steel. It is good practice to keep these materials separate.
They are not directly welded using carbon steel. Typically a 309 or Inconel filler metal is used.
Only with a suitable filler metal made for dissimilar metal welding.
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
This is why it not uncommon to see serious rust staining and pitting on SS decorative and architectural items, because fabricators and installers were not well versed in proper practice.
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P.E. Metallurgy, Plymouth Tube
RE: Why SS and CS material can not mix up in vessel fabrication time.......?[ponder]
Regards
r6155