Can pipe supports be welded using materials of a lower grade than those of the pipes?
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Here’s the situation: my pipes are made of duplex steel. When choosing elbow supports or dummy pipe supports, the pipes used in those supports are usually made of the same material as the main pipes. But in order to reduce costs, is it possible to use cheaper support pipes such as 304 or 306L to support the pipes?
Generally, materials from the same family can be used as substitutes~~~ Duplex steel consists of austenite and ferrite~. If the corrosion conditions at the site where it is used are severe (such as in coastal areas), there is a possibility of slow electrochemical corrosion occurring at the welds~~~ In an inland atmospheric environment, the corrosion rate is significantly reduced~~~ In my opinion, substitution is possible；
It is sufficient to insert a duplex steel gasket between the two materials.
Well, I asked the people on site, and they all said there should be no problem. In the past, the same pipe material was used, but now EPC projects focus on cost considerations
Use it as a makeshift solution; the properties of austenitic stainless steel are also passable.
A pipe with seams will do; use a wooden block as a spacer in between the pipe clamps
Since you’re using duplex steel, corrosion will definitely be severe; either use pipe clamps or place a duplex steel plate as a barrier – it’s hard to say what will happen regarding electrochemical corrosion
For such operating conditions, we generally recommend to our customers using rubber shims or wooden pads in the bracket chucks
The use of duplex steel is determined by the properties of the process materials; the material of the pipe support has no relation to the process pipes. If electrochemical corrosion is a concern, a PTFE sheet can be placed between the pipes and the pipe supports.