welded stainless steel exchanger tubes bead 2

[gengi]

Dear all,

I wonder if someone could help me on this topic.

I would like to know if, for the welded exchanger tubes (stainless steel) there are any requirement regarding the weld bead (internal & external) such as limit height.

There are Project Specifications which requires the welded tubes to be cold drawn for the redusìction of the weld bead but as far as I know the welded tubes are not cold drawn by the tubes manufacturers.

I recall a white paper which claimed a limit of internal weld bead height to a 10% of the tube thickness but I am not sure.

Your opinion/suggestion will be highly appreciated.

many thanks to everybody

gengi

 

[SnTMan]

gengi, SA-249 restricts the wall thickness at the weld to no more than 106% of the specified wall thickness or 0.004 in., the greater of. There are exceptions for various conditions

The general tube spec SA-1016 says for tubes 2" dia. and under a max height of 0.006 in. There are exceptions to this as well.

If this issue is important I suggest you check the relevant spec. to confirm.

BTW, SA-249 requires at least the weld metal be cold worked.

Regards,

Mike

 

[gengi]

Dear SnTman,

thanks a lot for your prompt reply!!

I mentioned that I found Project Specifications which require the welded tubes to be cold drawn for the redusìction of the weld bead.

As far as I know the cold draw is done for seamless tubes and I did not find any welded tubes suppliers which accept this requirements.

I have been told that anyway to apply the cold draw the welded tubes (in case someone would performe it)this would heavily affect on the welded tubes price so there is no convinience to use welded tubes.......

May be the requirements about the reduction of weld bead was a concern years ago when the manufacturing (i.e. welding) of the tubes was not excellent but now a day with the progress of the welding quality and since the tube weld i done without filler metal there is no concern about the weld bead since it is pratically negligible ( please also note that we are talking about shell & tube heat exchanger tubes and not tubes of FOOD BRANC).

What Do you think about it??

regards

gengi

 

[SnTMan]

gengi, in general, project specs must be met unless exceptions were taken previously, or unless the client will allow a deviation.

It seems to me that you will have to weigh the costs and deliveries of welded tubes per the project specs against seamless, if seamless is allowed.

Again, I would recommend you study the relevant ASME tube specifications to confirm whether they meet the project specs as is, or if you will need to add additional requirements to your purchase spec.

Unfortunately in these kinds of situations it makes little difference if the project spec requirements are "necessary" they still have to be addressed in some fashion.

Good luck

Mike

 

[Philrock]

Tubing that is welded then cold drawn is sometimes referred to as WDOM (welded and drawn over mandrel).