TWI Frequently asked questions
by Vic Wright
Austenitic flake graphite cast irons may be welded with a nickel iron electrode (AWS A5.15-90: ENiFe-Cl). This may also be used for welding the austenitic nodular cast irons although the choice of filler material is often more critical to obtain the requisite toughness and heat resistance. A Ni-Cu electrode has been used successfully, but a 20%Ni-Fe-Mg electrode has been developed to reduce cracking.
It is advisable to apply both preheat and stress relief in the welding of austenitic cast irons. Preheat of 320-330°C and post-weld stress relief of 600-620°C followed by slow cooling is appropriate.
All cast iron welding requires care. If in doubt, contact an experienced practitioner.
Further information on the above and other welding processes is available in:
Welding of cast irons - a guide to best practice
C.L.M.Cottrell, 'Welding cast irons', published by TWI, Abington, Cambridge, UK, 1986 and available from Woodhead Publishing, Abington, Cambridge, UK. e-mail: sales@woodhead-publishing.com
ISBN 0 85300 176 6
Guide for Welding Iron Castings - ANSI/AWS D11.2-89, American Welding Society, Miami, Florida, USA. e-mail: info@aws.org
ISBN 0 87171 295 4
