Up to 70 jobs could go at leading Sheffield-based manufacturing company Firth Rixson.
Around 50 jobs are under threat at its Meadowhall plant, where Firth Rixson is making a major investment in a new forging press.
A further 20 jobs are threatened at Firth Rixson’s River Don works on Milford Street.
Redundancy consultations are due to start on Monday.
The firm declined to comment, but it is understood to have told workers that jobs must go because of a decline in orders from leading customers.
Workers at the Meadowhall site have been told the order book is more than a third down on the £63 million worth that had been budgeted for.
The firm says, in a letter to Meadowhall staff, it has been trying to reduce the impact of the downturn by not using temporary workers, extending shutdowns and cutting hours in some departments.
It adds: “While the company’s goal has always been and will remain to retain skills and experience, it has now however become necessary to consider a reduction of our workforce in order to reduce costs further.”
The company said it will seek ways to avoid or limit job cuts, but is inviting staff to volunteer for redundancy.
One worker from the Meadowhall site said: “We had a briefing a week-and-a-half ago, and there was no mention of redundancies. They’re a good firm to work for but you can’t help feeling they were keeping us in the dark.”
The Meadowhall plant makes nickel, titanium and steel alloy forgings for the off-road automotive, aerospace, power and defence sectors.
The River Don site makes forgings from stainless and carbon steels, nickel superalloys and titanium alloys for the aerospace, mining and commercial sectors.