Cold Service Carbon steel 1

[daveb9]

We are manufacturing carbon steel valves for -30°C (-22F)servce I am looking for a steel specification for tube and bar that will operate at these temperatures with a minimum of pre and post weld heat treatment.

At present we intend to make most the valve from SA516-70N.

Dave

 

[deanc]

See SecVIII Div1,UG-20 and UCS-66.

 

[arto]

search on "low temperature" under "technical pages" @

http://www.nidi.org/

for nickel steels for cold service

 

[TomEun]

1. Preheating

When the PWHT is not required, the DBTT (ductile-Brittle Transition Temperature) of welds may be decreased because it can reduce the residual stress. However ASME BPV codes do not mention the mitigation of impact test exemption curve due to the preheating because it is difficult to prove the quality of the final product by the preheating.

2. PWHT (per UCS-56)

ASME Section VIII Div.1, UCS-68(c) permits the mitigation of impact test exemption curve due to PWHT (when it is not otherwise a requirement of this division).

3. Normalizing

ASME Section VIII Div.1, Fig. UCS-66 permits the mitigation (more than PWHT’s) of impact test exemption curve due to normalizing.

Thomas Eun

 

[jsummerfield]

As a valve purchaser I would rather that the line were a stainless specification. I am not found of the charpy modification restrictions.

John

 

[bvi]

Since you are manufacturing valves, you should not be going to the Pressure Vessel Code for information. You should go to the relevant piping codes (for the systems you want to put your valves in). For example, ASME B31.3.