There can be N number of joints in a bridge girder. Each such joint is listed by fabrication inspection agency, duly mentioning steel plate thickness, weld size, type of welding involved like SAW or FCAW etc., fillet or butt type etc. and also depending upon the position of weld like flat, horizontal, vertical or overhead. To understand this you can watch another video available on the channel by clicking I card popped above.
once all such different joints involved in a girder are listed, now it is decided what amperage, what voltage and what running speed is suitable to achieve each such joint. For each joint, one sheet is prepared containing these details. This sheet is called welding procedure specification sheet or WPSS. For executing welding involved in each WPSS, we need to have qualified welders. The welders are tested against these WPSS sheets through welder qualification test called WQT in short. Once a welder is qualified for a particular WPSS sheet or for a number of WPSS sheets, a certificate is issued in his favour that is called WPQR welding procedure qualification record. It qualifies a particular welder to execute certain number of WPSS sheets for which he has passed the qualification test.
This initial qualification once done can not remain forever. So time to time inspecting agency has to re alidade and renew these qualification records.
Conditions of welder qualification, their initial and subsequent testing, their revalidation etc. are dealt as per instructions issued by RDSO on this matter on 19.06.2023.
Now we will understand these in the form of question and answer.
Question 1- How a welder is considered qualified and approved?
Answer – Qualification of welder is examined by asking him to make a test piece as per an approved WPSS sheet or for a number of WPSS sheets. Once the test results are found satisfactory, the welder is considered initially qualified.
Question 2 – After initial qualification, for how long this certificate remains valid?
Answer– The certificate needs to be revalidated every six months otherwise the certificate becomes invalid.
Question 3– What are the conditions based upon which, successful revalidation of welder is done?
Answer– The conditions based upon which successful revalidation of welder is done every six months are as follows –
a) The welder is working for the same fabricator, same type of steel girder having the same span length and same WPSS under different projects/contracts.
b) The fabricatorr’s quality programme has been verified in accordance with applicable QAP and WPSS as per ISO 3834-2 or ISO 3834-3 or technically equivalent IS 15326 (Part-2 & 3)
c) The fabricator has documented that the welder has produced welds of acceptable quality based on application standards.
Question 4– maximum how many times this revalidation after every six months can be done.
Answer– For maximum three years. After 3 years the welder shall be mandatorily retested.
Question 5-Is WPQR issued against a welder is project specific and for each new project new WPQR is required to be done ?
Ans. – WPQR is not project specific. The same welder can be engaged for other project also. Reapproval is required if any of the following conditions apply –
a) A new welding procedure (WPSS) is involved with change of welding parameters,
b) If a welder remains idle that is Not deployed for welding for a period more than six months due to whatsoever reasons.
c) There is some specific reasons to question the welder’s ability like age or some illness etc.
Question 6- What needs to be done in order to use already qualified and valid welders for the next project involving similar welding?
Answer- Railway has to prepare a list of such welders who are already possessing valid WPQR and whom they want to deploy for the next project. This list along with necessary documents shall be submitted to inspection agency along with WPSS sheets involved in the new girder fabrication project. After scrutiny of the documents, fabrication inspection agency shall permit the names of such welder who can be deployed for the next project without reapproval.
Question 7– Who is supposed to conduct WQT, WPQR and retesting?
Answer– ‘Steel girder fabrication inspection agency’ is supposed to conduct these. In case RDSO is working as fabrication inspection agency, M&C (Metallurgical and Chemical) Directorate of RDSO conducts these tests and issues necessary certificates.
Hope this video has helped you in understanding the RDSO policy with respect to welder qualifications and their renewals. Also it will help you in utilising the already qualified welders for your next projects.
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