The power revolution caused changes in the industrial structure. A series of new industrial sectors were created. First of all, the production of electric power production industries, including generators, electric motors, transformers, wires and cables, and other electrical equipment industries, which are mainly based on power generation, transmission, distribution, and power consumption; the emergence of the instrument industry; electroplating, welding, electrolysis, and electrical sparks Emerging processing industries such as processing have emerged. The old industrial sector has made rapid progress due to the transformation of production technology, and the steel industry is a prominent example. In the middle of the 19th century, people had mastered the "blown gas refining" technology. Bayesian converters took root in many countries, but low-grade iron ore could not produce high-quality steel. In 1877, British technician Thomas invented the alkaline converter steelmaking method. To solve this problem. In 1864, the Frenchman Martin and the German Siemens brothers simultaneously announced the invention of the open hearth steelmaking method; at the end of the 19th century, electric furnace steelmaking was successful, and after continuous improvement, by the 1970s, electric furnace steelmaking already accounted for 18% of world steel production. American steel output reached 44.9 million tons in 1923 and increased to 56 million tons in 1929, an increase of 26%. The rapid development of heavy industry has gradually increased its proportion in the national economy. In the 20th century, it surpassed light industry and became the pillar industry of the national economy.