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DriveIndustrial steel fact

The Bessemer process, patented by Henry Bessemer in 1856, made steel by blowing air through molten iron to burn off excess carbon and other impurities. It made steel cheap enough to build railways, bridges and ships.

British patent, 1856

EngineeringTechnologyHistoryBusiness

The story behind the card

Bessemer's converter was a large pear-shaped vessel lined with heat-resistant brick. Air blown in from below burned away carbon, silicon and manganese, and the burning itself gave off so much heat that the iron stayed molten without any added fuel. Three to five tons could be turned into steel in 10 to 20 minutes, a job that had taken at least a full day of heating, stirring and reheating. The early process could not remove phosphorus, so it worked only with scarce phosphorus-poor ores until 1878, when Sidney Gilchrist Thomas and his cousin Percy Gilchrist introduced a converter with a basic, limestone-type lining. The price of steel fell from about £40 a ton to £6–7.

Türkçe oku
Bessemer yöntemi, erimiş demirin içinden hava üfleyerek çelik üretir: hava, demirdeki fazla karbonu ve öteki safsızlıkları yakar. Henry Bessemer'in 1856'da patentini aldığı yöntem, çeliği demiryolu, köprü ve gemi yapımında kullanılacak kadar ucuzlattı.
İngiliz patenti, 1856

Bessemer'in konvertörü, içi ateşe dayanıklı tuğlayla kaplı, armut biçimli büyük bir kaptı. Alttan üflenen hava karbonu, silisyumu ve manganezi yakıyor, bu yanma o kadar ısı çıkarıyordu ki demir dışarıdan yakıt eklenmeden erimiş kalıyordu. Üç ila beş ton demir 10–20 dakikada çeliğe dönüşebiliyordu; aynı iş daha önce en az bir tam gün ısıtma, karıştırma ve yeniden ısıtma gerektiriyordu. İlk yöntem fosforu gideremediği için yalnızca az bulunan, fosforu düşük cevherlerle işe yarıyordu. 1878'de Sidney Gilchrist Thomas ile kuzeni Percy Gilchrist, içi kireçtaşı türü bazik bir astarla kaplı konvertörü geliştirince bu engel kalktı. Çeliğin tonu yaklaşık 40 sterlinden 6–7 sterline düştü.

Sources and further reading

Background reading: Bessemer process
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