The cuts will hit several parts of the UK, particularly in the West Midlands.
Caparo is the latest UK steel producer to hit troubled times in recent weeks. Last month, SSI announced it would mothball its Redcar plant with the loss of 1,700 jobs.
Unions said ceasing production would have a devastating effect on Teesside after a 170-year history producing steel.
Tomorrow the steel firm Tata is expected to announce the loss of 1,200 jobs at plant in Scunthorpe and Scotland.
Global steel prices
Steel firms blame the closures on a worldwide reduction in steel prices.
In the late 19th century, Britain led the world in steel production. But it has been in rapid decline since privatisation in the 1980s, when the government stopped subsidising loss-making plants.
The job losses come at the start of a four-day visit to the UK by Chinese President Xi Jinping. China is selling steel to international markets at discounted rates in order to maintain production.
UK imports of Chinese steel were 2 per cent of UK demand in the first half of 2011. That figure is expected to rise to 8 per cent this year.
The steel firm Caparo is owned by Labour peer Lord Paul.