Henry Bessemer (1813—1898)

Henry Bessemer was born in Charlton, Hertfordshire, England. His father was a French emigre who had escaped the Revolution to become an engineer and type founder in England. The young Henry demonstrated the same prowess as his father in mechanical ability and interest in engineering and invention. Indeed, his father was so elated that he often permitted Henry to skip school and perform experiments in his workshop at home.

At the age of 17, Bessemer journeyed to London to peddle his various ideas. He dabbled with the concept of wax casts for sculptors but found no takers. He also invented a die cast to impress ornamental scrollwork on Bibles, but this endeavor also failed to attract any investors. Finally, in 1832 he achieved success when he invented a device—a ‘‘gold dust’’ machine—that ground up the pigment for the gold paint used in decorating china. He made a fortune as his secret formula was adopted to adorn a sizeable portion of the gilded decorations of his era.

Bessemer married and purchased a home in London. At this point he sat poised for his greatest contribution: cheaper steel production. His steel process is the perfect example of how military considerations can influence technological development. During the Crimean War he experimented with new types of artillery projectiles. He first developed the idea of a spinning projectile whose motion provided a better trajectory to the intended target. Because the British military was not receptive, he approached the French. The French government expressed interest but one serious problem needed resolution. At times the projectile exploded prior to exiting the cannon tube. Bessemer saw the necessity of creating a stronger artillery piece. This realization set him off on a new course. Steel was a natural material and had long been produced. To be sure, the Chinese had manufactured steel for nearly a millennium, although their process, known as the ‘‘hundred refinings,’’ was extremely slow as the name itself suggests. In the early 19th century steel was scarce and expensive to produce because of the existing inefficient method to remove carbon from the iron ore. Thus, steel was not available for larger construction projects such as railroad rails, bridges, ships, etc. These structures were made of wrought iron created from a process known a puddling, a procedure that not only was expensive but also demanded workers who possessed strength, endurance, and skill. The belief in Bessemer’s day was that cast iron had to be converted to wrought iron by removing as much carbon as possible and then be converted to steel by the reintroduction of carbon. The steel produced in this manner retained a higher percentage of carbon than Bessemer deemed acceptable. Furthermore, previous methods of making steel took up to ten days by heating powdered charcoal to a red-hot capacity. This method produced only minimal batches of expensive steel and was used to make merely small implements such as tools, cutlery, and machine parts.

After much study Bessemer concluded that cast iron could be transformed to steel in one step by applying a dedicated blast of cool air to the molten iron. His contention was not widely accepted initially, as most persons associated with steel-making thought that cool air would likely cause the iron to gel before it could be manipulated. Bessemer set out to prove them wrong. He constructed a large, fully equipped workshop with a large egg-shaped furnace to aid in his experiments. Bessemer further modified his furnace with a perforated bottom to allow for the blown air to be introduced through the vents. This furnace became known as the Bessemer converter and is the real key to his contribution. The converter itself was constructed of steel and lined with silica and clay and mounted on supports or trunnions that enabled the converter to tilt forward or backward. In the initial step, a blast of cool air was applied and one-half ton of molten pig iron was poured into the converter. The oxygen from the air kept the mass ignited, thus negating the need for additional fuel. After the mass quit burning the converter was tilted to pour out and remove the impurities such as silicon, manganese, and carbon in the form of a slag. The remaining pure mass was poured into ladles from which the now malleable steel was emptied into molds. The whole process lasted no longer than fifteen to twenty minutes, and the larger converters could Handle from eight to thirty tons. The typical output was twenty tons in twenty minutes. Bessemer’s approach, also referred to as the pneumatic conversion process, not only promised to hasten the production of steel but also greatly reduce the associated financial costs.

In 1856 Bessemer received a patent for his process to manufacture steel without additional fuel. His patent claimed that he had developed ‘‘the fusion of steel in a bath of melted pig or cast iron in a reverberating furnace, as herein described.’’ He then set out to construct the Sheffield Iron Works. Interestingly, an American, William Kelly, was simultaneously working on the same process as Bessemer. To his ultimate chagrin, Kelly had kept his experimentations private and did not initially seek a patent. And, no evidence exists to suggest that Bessemer had any inkling of this independent effort. About a year after the Bessemer patent, Kelly obtained an American one, although by that time Bessemer’s steel process and quality had secured a positive reputation that led to a rapidly expanding business. Thus, Kelly’s operations never achieved anything approaching the level of success of Bessemer’s process.

Bessemer enjoyed tremendous financial success, and his process had far-reaching ramifications. His patents resulted in a five-million-pound profit. And, by the late 1860s, Great Britain was producing

110,000 tons of steel annually. Steel was first used in the construction of railroad rails in 1857. His steel beams were employed in the construction of the earliest skyscraper, the Chicago Home Insurance Building in 1884. In 1878 Sidney Gilchrist Thomas used the Bessemer process to remove phosphorus from steel (Bessemer had used phosphorus-free ores thus restricting his selection). Ten years after Bessemer’s patent, Charles and Ernest Siemens and their partner, Pierre-Emile Martin, introduced the open-hearth system. Bessemer himself liked to cite the British Prime Minister, William Gladstone, who remarked that the Bessemer patent was a near approximation of the later Siemens-Martin patent. Nonetheless, the upshot of the efforts begun by Bessemer and followed by Kelly and the Siemens-Martin team resulted in a dramatic increase in the world’s production of steel from 0.5 million tons in 1870 to twenty-eight million tons in 1900. However, Bessemer converters remained in limited use until finally discontinued in the 1970s.

Henry Bessemer was a tireless inventor. Among his subsequent inventions were the steamship cabin, which remained stable while the ship rolled in order to preclude seasickness, a solar furnace, an astronomical telescope, and a diamond-polishing machine. In the end Bessemer held 120 patents, although none would have the significance of his Bessemer converter and steel-making process. Unlike the experience of many inventors of the Industrial Revolution, Bessemer’s achievements were recognized during his lifetime and he achieved substantial financial reward. He became a member of the Royal Society in 1877, and Queen Victoria knighted him in 1879. Although his steel production process did not reach its fruition until he was in his seventies, it was without a doubt the most important development in the steel industry. Indeed, in the opinion of many observers, the Age of Steel that Bessemer helped to usher in ranks in importance with the Bronze and Iron Ages of the past. Thus, steel, along with iron, became the underpinning of modern industry and transportation as lighter and stronger steamships became the norm for passenger travel and hauling cargo in a burgeoning worldwide marketplace. Upon his death in 1898, his admirers could attest that the industrialized world would have taken a different course without Henry Bessemer.