the bessemer process was the first inexpensive process for the mass production of steel from molten pig iron before the development of the open hearth process the process revolutionized steel manufacture by decreasing the cost from 40 pounds per tonne to 67 pounds per ton along with increasing the scale and speed of production it is an extremely important invention because it enabled the manufacture of stronger metal machines and innovative architectural structures in addition cast iron rails were replaced with steel rails because they lasted 10 times longer as a consequence of this invention the industrial revolution moved from the age of iron to the age of steel the construction of the pessimist converter consisted of a pear-shaped steel frame which is lined with fire clay bricks to resist the high temperatures developed during the process excessive temperatures are prevented by the application of scrap iron to the converter the process itself began with the pouring of molten iron together with an addition of lime at a temperature of 1300 degrees c into the mouth of the converter [Music] a blast away under high pressure was then applied to triers located at the base of the converter initially the silicon and manganese impurities present in the molten iron are oxidized to produce a slag in combination with a lime addition as this process finishes the oxidation of the carbon to carbon monoxide gas is initiated as evidenced by the blue flame at the mouth of the converter each of these oxidation processes is exothermic and during the 20-minute blow the temperature rises to 1600 degrees centigrade where in addition rocking of the converter on a central pivot is the dispersion of both air and scrap iron within the molten iron slag is skimmed off the surface of the steel and at the end of the blow the converter is tilted on the molten steel poured into ladles additives such as ferro manganese and ferrous silicon are added as the molten steelers pour into the label to achieve the final chemical composition of steel required process is continuous from start to finish the best similar process produced up to 30 tons per blow compared to 400 tons with a modern boss process in a typical processing time of 40 minutes newer iterations of the process in principle work and operate in a similar manner newer designs incorporate a combination of bottle blow with high speed top block this combined blow ensured both temperature and composition were homogeneous and the process became relatively quicker [Music] you