Thank you very much Sir Richard for your valuable input.

As far as I understand I have to add this material to CAESARII material database. I have found allowable stress only for temp. 21 and 149 deg.C and yield stress appears to be the same for both temperatures. Is this information sufficient for performing stress analysis or I need to dig deeper into properties if my temperature range for stress check is beyond mentioned above (lower than 21 deg.C)?
And where I can find fittings weight-dimension information for modeling and SIFs for branch connection?

Please kindly advise and thank you in advance

Vikoll