Steel giant Corus has announced plans to cut 400 posts from its distribution business, including 100 in the West Midlands.
The proposed job losses will also include almost 100 in Shotton, North Wales, 50 in South Wales and 50 in Leeds.
The company said that since the start of the year, its distribution business had been operating in a "volatile and fluctuating" market. It said: "The impact and continuation of the global economic downturn is having a major effect on steel customers in the automotive, construction and plant and machinery markets. Since September, the business has seen a significant decline in demand.
"As a result, Corus Distribution has introduced a series of actions to reduce expenditure on transport, consumables, energy and other discretionary spending. However, these actions alone will not be sufficient to offset the decline in the market."
Corus said it will start an immediate consultation with workers and will try to achieve the job losses through voluntary redundancy.
"Corus Distribution is committed to ensuring it will do everything possible to assist those people leaving the business, and will be putting in place a range of support services designed to help them through this difficult time," said the company.
The distribution side of the business employs 2,400 workers at 36 sites in the UK and Ireland. The proposed reductions will be spread throughout the business.
Roy Rickhuss, national officer at the steelworkers' union Community, said: "Community is disappointed and saddened by the announcement by Corus that there will be widespread redundancies within the Distribution Division.
"Support will be available from Community's education and training arm, Communitas, to help redundant workers retrain and find new employment."