Bessemer Converter

Bessemer Converter Kelham Island Museum

The Bessemer Converter is one of only three converters left in the world.

It was used by the British Steel Corporation in Workington until 1974/5 and produced the last Bessemer Steel made in Britain in 1974. It was brought to the Museum in 1978 as an example of the revolutionary steelmaking process which first took off in Sheffield.

The Bessemer process - the conversion of iron into steel - was invented and patented by Henry Bessemer in 1856. The egg-shaped converter was tilted down to pour molten pig iron in through the top, then swung back to a vertical position and a blast of air was blown through the base of the converter in a dramatic fiery ‘blow'. Spectacular but dangerous flames and fountains shot out of the top of the converter. The converter was tilted again and the newly made steel was teemed or poured out. The first converters could make seven tonnes of steel in half an hour.

In 1858 Henry Bessemer moved to Sheffield and licensed his method to two steelmakers, John Brown and George Cammell, who both began to produce Bessemer Steel on an unprecedented scale by 1860. Others soon followed and within 20 years, Sheffield alone was producing 10,000 tons of Bessemer steel every week (this was almost a quarter of the country's total output). The invention marked the beginning of mass steel production, as huge amounts could be produced in a relatively short time compared to crucible steel production. The steel was most widely used for the railways that were stretching around the world.