Attach the two materials with compression fittings, threaded fittings or by welding.

Are you using a mandrel for bending?

Spring coil bending?

You could fill the pipe with sand, cap, and bend. then remove sand.

Fill the pipe with water, freeze the water and bend.

Thanks Guys,

other than fittings (flange, threaded fitting), is there any method to combine this material?? i cannot use fittings due to spacing problem.

Welding.

Use brass bushing between the stainless and the copper. Lyn suggested sand bending, this would be my choice also. A trap for young players with sand bending is the sand not compacting all the way through, and the smaller the diameter the harder it is to achieve this. Just take it nice and slow, but make certain the sand is very dry. If the sand has any moisture content and you try to re-anneal, you will get a blow out. Don't forget to clean the pipe inside and out after the bending is finished.

Good luck on this project

"Use brass bushing between the stainless and the copper"

What copper?????????

Exactly!!!

CS is not short for copper stuff...carbon or cast steel more like it.

Yup..Cs stands for carbon steel...not copper..sorry..

Weld or braze to join.

Depending on how much the walls thin when stretched during the bend will determine whether your material still fits the bill.

How tight are your bends? Bend a bit of it, cut through the bend and measure the wall thickness.

the pipe will be bend to form hexical shape (like spring)..my consideration is about the safety factor because the water is in very high pressure.

Project Requirement:

"If material compatibility is not possible (like carbon steel to Duplex stainless steel with the presence of conducting medium for example), then the connection shall be provided with a suitable flange isolating kit made from non-conducting material".

i CANNOT USE FLANGE DUE TO SPACING PROBLEM. THERE IS ONLY SMALL GAP EXISTED.

the pipe will be bend to form hexical shape (like spring)..

Do you mean it crumples on the inside of the bend or that whole tube is corrugated and therefore inherently flexible or that the final shape is that of a coil and the bends are not a tight radius?

Please describe what and where the joints are. Are you connecting ss tube to cs tube for the fluid path or what? If it is a simple tubing joint then the non conducting material statement makes sense otherwise....

Why not to change the 1/2" pipe to stainless steel pipe ? ! ?

Do you produce many sample coolers?

-If only one / several units - the price difference versus work perform and quality acchieved per full assembly cost - is not relevant

What possible benefit would changing to SS have?

None that I can see.

Quite simple benefit:

No corrosion , no special fittings , better looking (cleaner) device , stronger material

- I am sure there is more !! Please add....

Some photo, sketches, drawings, URLs et al would come in handy at this stage of the guess-fest.