Introduction
The AWS Global Welding Engineer developed the Category program in response to a request from plant integrity engineers to address specific knowledge, skills and Qualifications for welders working FiFO at Santos. The CAT training and qualification system has 10-parts related to Welding and Plant Maintenance in Oil and Gas
facilities.
welder qualifications
All welder qualifications require the welder to be competent. Competence is a factor of knowledge and skills, to which we include welder qualifications in accordance with ASME or AS. These are Welding Procedure based training and qualification programs specifically to address plant integrity and reliability.
The concept and design of the CAT programs has been developed by the AWS Team over 15-years to mitigate plant operational risks, improve reliability and reduce repair rates.
Over the years numbers of welders completing the Cat programs has waned as changes in field engineers and contractors have occurred. It remains that the integrity of pipelines and plant is reliant on knowledgeable and qualified welding personnel performing critical welding services for plant. Its cheaper to train and qualify welders before they fly into site.
The lead integrity engineers acknowledged the Cat programs as a key improvement to the asset integrity and reliability of the plant. As such sanctioned a series of CAT programs each designed and developed to meet demand incorporating welding procedures in accordance with the plant specifications.
The CAT concept has been varied and applied to other industry sectors including defence to train welders for specific projects or industry sectors based on the Welding Procedure applications.
CAT-1
The Cat-1 program is based on the welding of small-bore fittings.
The AWS Welding Engineer for Santos implemented GTAW with S2 class wire for service down to minus 45 C to replace the practice of using cellulosic electrodes in the welding of fittings.
Back in the day cellulosic electrodes were commonly used on plant pipe systems leading to poor profile stress raisers, high hydrogen deposits, fusion defects, dross inside the pipe and fittings resulting in pump set plant failures.
CAT-1 includes 2-hour theory module on relevant topics including the correct assembly and weld profile completed to the weld margin and a smooth transition to the carrier pipe in accordance with B31.3.
The welder completes face to face theory and an assessment. Following this program the welder moves into the welding facility and needs to complete an assembly which includes WeldOlet, 50NB butt weld
and SOW joints.
The butt weld is subject to RT, the WeldOlet and SOW are subject to macro. This combination of non-destructive and destructive testing has revealed fusion defects in WeldOlet and SOW joints caused by pushing excessive rod into the puddle, a skill error which would otherwise have been overlooked.
CAT-1 remains a core skill and qualification for welders in the Cooper Basin.
CAT-2
The aim of the Cat-2 program design is to ensure the integrity of welded low
temperature service CMn Steel pipe systems. Santos has experienced a cold box failure.
There is a distinct gap in the TAFE training of welding personnel when it comes to the welding of low temperature service materials. Therefore, appropriate application training is imperative for welders and supervisors involved in the welding of notch tough materials. It is our experience that the consequence of brittle failure is a mystery to most.
Cat-2 theory discusses the low temperature specifications, ductile to brittle
transformation, the correct Welding Procedures, the correct run placement
technique, and the selection of the correct welding filler metals for low temperature service.
Cat 2- includes the GTAW welding of a 50NB pipe butt weld and the GTAW / SMAW welding of a 150NB pipe butt weld.
CAT-2 remains a core skill and qualification for welders in the Cooper Basin as it introduces SMAW 6G Pipe qualification.
CAT-2 focuses on CMn steel; however, CAT-4 discusses low temperature service for Austenitic stainless steels.
Want to know more?
If the AWS CAT Programs are of interest to your organisation, please contact us to discuss how we can assist.