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 inconel.
- Three top tips when welding Inconel are:
- All common welding processes can be used to weld inconel.
- TIG is always preferred process to weld inconel as it has better weld bead control.
- Always take great care in choosing weld consumables as there are so many different nickel based alloy variants that consumables can be better suited to slight differences in parent material composition.
2. What equipment is required?
- Inconel is heavily used in cladding of lesser and cheaper materials usually, so automated welding plant would commonly be used but for this piece we will go with manual TIG welding so any decent water cooled TIG plant is fine.
3. What preparation is key?
- As Nickel alloys are similar to stainless alloys in that cleanliness is of high importance as well as back purging when performing single sided welds to prevent oxidisation (coking). A clean surface at least 2” either side of the weld zone is critical to prevent porosity forming in the weld.
4. Key challenges and how to overcome them:
- One of the biggest problems faced when welding Inconel is hot cracking due to low melting point impurities forming at the centreline during solidification, this can be combatted by additions of manganese and Niobium in the filler wire. Also, as the weld pool of nickel alloy tends to be very viscous a certain level of weaving is required to ensure penetration at the weld toes.
5. Safety considerations
- These considerations of health and safety rarely change when discussing the welding of any steels be they carbon or alloy we will always have inhalation of chemicals and materials alike. Respiratory protection is one of the major issues being raised for welders at the moment so ventilation, extraction and RRP are major considerations.