post weld heat treatment A333 2

[paulbrown]

Do you need to PWHT fillet welds in A333 gr6 pipe
for propane duty down to -43degC ?

 

[metengr]

To answer your question, what Code or Piping Standard are you working under - ASME B31.3 or B31.4 Process Piping Standard or other? Also, what is the pipe size/schedule?

Second question - are you sure about fillet welds or are these butt welds with external fillets applied like a branch connection or combination or are you welding attachments to existing piping? Please be specific.

 

[DSB123]

Why are you using fillet welds on Propane duty? Butt welds are a much safer proposition.

 

[paulbrown]

We are working to B31.3, pipe is 3/4" sch. 80 and the reason we are using socket weld fittings is because that is the existing site standard.

 

[metengr]

No PWHT. I checked B31.3, Table 331.1.1, for 3/4" wall thickness and less for P-No 1 base material, no PWHT.

 

[paulbrown]

metengr.
I know B31.3 says no PWHT for P 1 materials but, do environmental conditions change the requirement for PWHT even though is not mandatory.

 

[metengr]

No. ASTM A 333 Grade 6 is basically a medium carbon steel with 0.2-0.3% Mo. This is a weldable grade of steel, considering Section IX treats it like a P-No1, Group - No1 material. For your application, this material should pose no problems without PWHT.

 

[DSB123]

Paulbrown,
metengr answers your question explicitly. It's what I advised Reg anyway!!!

 

[paulbrown]

Thanks Metengr.

DSB123 - We don't usually get to know whether questions have been asked or answers given !!!

 

[stanweld]

Paulbrown,
As metengr has stated, B31.3 does not require PWHT for the low temperature service. Furthermiore, it is not common practice to PWHT with the design described; however, service conditions, as determined by the designer, may dictate otherwise. "In such cases, the designer may specify more stringent requirements in the engineering design, including heat treatment.." (ref. 331.2.2)