Breaking the mould

Sheffield Forgemasters International (SFIL) has developed a new vast ingot mould to make forgings for some of the world’s largest steel mills.

The company is re-engineering its moulds to create ingots which will be forged into the largest steel rolls for Siemens VAI, to work in the steel-plate producing mills of India and east Asia.

The new mould will enable Forgemasters to create steel rolls which will produce sheets of steel up to 4.5m wide – more than one metre wider than generally produced - to feed the ship-building industries in economically developing regions.

Dr Martin Kearney, technical director for the engineering arm of SFIL, said: ‘Forged rolls of certain sizes make up a very high demand market because there are relatively few companies across the globe able to produce such castings and forgings.

‘The new ingot size means we will be producing a finished roll weighing approximately 170 tonnes. To do this, the ingot we work from needs to be closer to 300 tonnes.

‘The benefits of these large roll sizes are that the steel sheets they produce are wider. This saves massive amounts of welding time on large-scale constructions, but more importantly, constructions using less welding require less inspection for material fatigue along those joints.

‘Siemens VAI has worked very closely with us on this project to create an optimum size of ingot for forging the rolls.’

SFIL has used the skills of its subsidiary design and project management company, Vulcan SFM to work out the process for making ingots of this size.

Paul Mockford, Design Director at Vulcan SFM, said: ‘There is much more to consider when increasing the size of a casting mould than adjusting the diameter or length of the mould. We use Finite Element Analysis at all stages of the process to ensure that the finished castings are of high integrity.

‘Factors such as the vacuum time for the molten steel, the pouring rate and the cooling temperature and duration of solidification for the cast steel are vitally important to prevent structural defects forming in the ingot.’

The two-year development of ingot sizes has taken Forgemasters’ stock production from 2.7m in diameter, to 2.9m before creating a mould for ingots of 3.3m diameter.
Forgemasters aim to cast the first of the new 300 tonne ingots in October.