How would you qualify a welder for low temperature service?

selection of pipe material for low temprature service.

1.Requirement Code Eg-ASME SECIX,API1104,AWS D1.1.

2.PWPS,DIA,THICKNESS,POSITION,PROGRESS,F.NO,NDT.

1st preparing pWPS then DT & NDT as the Results are accepyalble & comply all Essential/Supplymentary/Non Essential Variables According to ASME IX (Latest) QW-200 or Related Code & standard , WPS prepared.

2nd aplly for WQT or performance Qualification as same results are accepted on the behalf of sound weld comply with  Essential/Supplymentary/Non Essential Variables according to ASME IX QW-300 , welders is Approved.

3rd as the Question is Welder Qualification for Low temprature service there is Supplementary Variable is Impact Test  required as Destructive Testing.

To qualify a Welder Manufacturer/Contractor shall have approved PQR & WPS in place as per Test Code ASME Sec IX.

We are qualifying as pe r ASME sec IX, for LTCS we are doing additional bend test also.

Welder shall be qualified as per Test Code mandated by main construction Code

To qualify a Welder, Manufacturer shall have approved WPS in place as per Test Code. 

All Essential welding variables required by Test Code shall be complied.

Low temperature service (Impact Test requirements) are non essential varibales for Welder Test. So Welder qualified on materials (Low/ Medium/ High) is qualified for all materials (low, medium & High Temp service).

Each manufacture or contractor must shall be required to prapare procedure qualification record which is defined as follows ;

PQRs (Procedure Qualifiecation Record)

PWPS ( Pre Welding Prosedure Specification)

So the most important thing is to make a qualified welder test is a Welding engineer must know how many degrees of ambient temperatures are allowed in cold areas. For europe region which allowed for welder in test with temperature below -29 degree celcius, with tensile temperature test.