AJAX furnace

The AJAX process invented in 1957, and named after its originator, Albert Jackson. The process involved modifying an open hearth furnace to use oxygen instead of air.[1] The use of oxygen in the open hearth negated the need for an external fuel source, as with Linz-Donawitz converters.[2]

The furnaces were used at the United Steel Companies at the Appleby-Frodingham steelworks near Scunthorpe, Lincolnshire, England as an alternative to installing completely new oxygen based steelmaking plant. In operational practice at Appleby-Frodingham the design initially increased productivity by 38%, as well as reducing scrap requirement from 3.5 to 0.2 long hundredweight (178 to 10 kg) per 1 long ton (1,000 kg). Later productivity increases were from 70% to 100%, with conversion costs reduced to 68%.[3] By 1962 five of the six open hearth furnaces at the plant had been converted.[1] Conversion time of the open hearths to the oxygen-based process was around 28 days on average, with a stated capital cost of £180,000 each.[4]

In 1966 the Appleby-Frodingham steelworks decided to replace the AJAX production with Linz-Donawitz (LD) converters.[3]

• Kaldo converter