Material selection for steel in low temperature service?

[pacesetter]

Hello,

I have a various structures that are being certified to ABS for underwater vehicles. Most of the structure is specified as A572 GR 50 or A516 GR 70 plate or W flange. However, I need some square tube. Will I have to go to stainless steel to get CVN's of 25 ft-lbs at -20F. Or, is there some type of steel that I can consider?

Thanks a bunch!

 

[metengr]

pacesetter;
Have you reviewed the ABS rules? If not, go to the web site below and sign up (for free) to obtain information regarding materials of construction under ABS rules.

http://www.eagle.org/absdownloads/index.cfm

 

[pacesetter]

Yes, this structure is part of the handling system. Section 11.1 of Appendix 4 only states that the materials are to be suitable for intended conditions.

 

[metengr]

There are structural steel shapes under ASTM Specifications that can be used for moderate to low temperature service. I don't have the information handy. However, you can access the web site below and perform a search function to locate applicable material specifications;

http://www.astm.org/cgi-bin/SoftCart.exe/index.shtml?L+mystore+gyhm8818