BAE Systems blamed the closure plan for the former Vickers plant in Scotswood on fewer Ministry of Defence orders.
Now neighbouring defence and construction giant Reece Group has signed a deal with BAE to take on the factory for an undisclosed sum.
Reece plans to transfer work from existing sites into Scotswood.
Reece already employs about 500 people and hopes to expand the workforce at its new premises over time.
The Group includes Pearson Engineering, which designs and manufactures a range of military equipment for customers, including BAE Systems. It also produces equipment for oil and gas fields.
Chairman John Reece said: "This landmark site will be fully used as a manufacturing facility. We have also acquired plant and machinery no longer required by BAE Systems which will be used to support our activities in the oil and gas, and the subsea markets.
"We believe that engineering and manufacturing still has a valid and prosperous future in the North East.
"We place great emphasis on research and development and our investment in Scotswood will include the establishment of the Reece Innovation Centre, whose focus will be to design the group's next generation of innovative engineering products."
A former tank factory in Newcastle, which closed last year with the loss of 300 jobs, has been bought by a rival engineering firm.