Seamless and welded tubes

[aida2011]

Hi all,

I was told by a friend that:

1) Only seamless tube is allowed for superheaters, regardless of temperature. According to him, all types of welded tubes are not allowed for superheaters. I know carbon steel ERW SA178 is used for medium and low-pressure boiler, but I also noticed some ERW low alloy tubes have some creep resistant properties, such as SA-250 T22 (1Cr-0.5Mo,) so it's possible to be used for superheaters.

2) The maximum allowable pressure to use the welded tube is 60 bar, because of more than that, there's a risk of seam tearing.

Thanks for your help.

Aida

 

[metengr]

You have been told nonsense. Seamless or welded tubing are permitted in boiler construction with the appropriate knockdown (weld reduction) factors as stipulated by the code of construction.

Example
SA-178, Electric‐Resistance‐Welded Carbon Steel and
Carbon-Manganese Steel Boiler and Superheater Tubes

SA-250, Electric‐Resistance‐Welded Ferritic Alloy‐Steel
Boiler and Superheater Tubes