As part of our top tips series, we will be undertaking a Q&A with Paul Flynn – an experienced Supervisor at John Tracey Specialist Welding, each month, focusing on the range of exotic metals the team work with. This week, it is super duplex.
1. Three top tips when welding super duplex are:
2.What equipment is required?
Air/water cooled TIG inverter, oxygen meter, bungs and dams, purge hoses/tape, digital thermometer, project specific tools and consumables.
3. What preparation is key?
Whilst there are a number of preparations to carry out before welding Super Duplex, I would pay special attention to purging. As with carbon inclusion, there are excellent ways and means of removing these contaminants but if your purge is wrong when you begin welding then it is already too late.
4. Key challenges and how to overcome them:
When welding full penetration Super Duplex pipe butts it is very common for the butt to shrink and close in causing great problems rooting. This can easily be countered with the use of the correct amount of bullets/inserts to hold the welded joint firm. There is a delicate balance regarding heat when welding Super Duplex; you should be looking to keep an inter pass temperature between 125-150 to prevent unwanted intermetallic phases.
5. Safety considerations
As with all welding, respiratory health problems are a major issue and as such extraction, ventilation, air-fed systems and a general awareness and respect for the dangers welding as a whole can pose.