The modern blast furnace operation at integrated steel works in Japan has started in 1901 by the first blown-in of Higashida No. 1 blast furnace in Yawata Works, while a 150 years history of Japanese steel industry has dated back to the first western blast furnace built by T. Ohashi in 1857. The steel industry has been supporting the Japanese economy as a key industry which supplies base materials for social infrastructure and developments throughout the pre and post war periods. After the recovery period from the war destruction, Chiba Works of Kawasaki Steel Corp., were built and started its operation in 1953 as the first integrated steel works in Keiyo Industrial Region after the war. During the rapid growth period, many coastal steel works equipped with a large blast furnace more than 3000m3 and some of 5000m3 were built for the efficient marine transportation of raw materials and steel products. Most advanced technologies, high pressure equipment, stave cooler system and bell-less charging system etc., were introduced, improved and has risen to the top level in the world with low reducing agent ratio (RAR), energy saving and long service life of a blast furnace and coke ovens. Energy shift from oil to coal by the oil crisis, cost oriented operation design and technology were tackled and the hot metal of about 80 million tons is manufactured with 27 blast furnaces including over 5000m3 large scale blast furnaces in 2012. During this period, our industry has faced many economical and social pressures of high exchange rate of yen, oligopoly of mining market, global warming problem, and surge of iron ore and coal prices by the rapid growth of the BRICs. We have kept our competitive positions by developing advanced technologies on pulverized coal injection, extended use of low cost iron resources, recycling for environment and CO2 mitigation technologies. Prospects of ironmaking technologies for other decades are discussed by reviewing various papers published and looking back the history of ironmaking developments during the last 100 years.
Progress of steelmaking technology in Japan over the last 100 years is reviewed covering hot metal treatment, primary steelmaking with open hearth furnaces, converters and electric arc furnaces, secondary refining of steel with degassers and ladle furnaces, and ingot-/continuous-casting.Key issues that contributed considerably to the progress of the unit processes are highlighted with scientific, technological and engineering breakthroughs involved. Systematization of the unit processes, that optimized full cost, productivity and quality of steel products to meet the constraints on the resources and socioeconomic demands of the steel market at times, is depicted as another key issue for the successful systematization.Possible future development of steel technology is briefly commented on the basis of the above observation.
This review gave an outline about effectiveness and the energy saving of the steel process. The main points are that the example of the energy-saving action of the iron and steel making process, using of by-product gas and waste heat recovery, technique to reuse by-producing slag or dust effectively, technique to use the waste such as the waste plastic and waste tires which occurred in society by using steelmaking processes effectively. The energy efficiency of the steel industry of Japan becomes the world’s best level by these actions. Finally iron and steel are superior material in the resource sustainability because iron and steel after the use can be almost recycled by using of the blast furnace method and the electric furnace method if it can be collected.
The history of construction of thick plate mills in Japan and trends in the development of rolling technology (gauge control, plan view control, and crown control) during the 100 year history of plate technology in this country are discussed in outline, and the Thermo Mechanical Control Process (TMCP) is reviewed. In 1901, the blast furnace at the state-owned Yawata Steel Works was blown-in and the medium gauge plate mill was started up, followed by startup of a 3-high rolling mill in 1905. Today, Japan has an annual thick plate production capacity of more than 10 million tons. Various important technical advances have also been achieved over the years, including gauge control, plan view pattern control, and crown control. The Thermo Mechanical Control Process was applied to controlled rolling for the first time in the 1960s, and accelerated cooling was applied in the 1980s. These technologies first reached full maturity in Japan and are now global technologies. The heat-treatment on-line process was also developed and continues to be a world-leading technology.
Development in sheet steels has progressed with a strong relation with automotive industry in Japan. To meet with the requirements from automotive industry, various types of sheet steels including high and ultra-high strength steel sheets have been developed. Progresses in three types of steel series will be discussed by checking the historical facts and technologies and their contributions. Introductions of interstitial free (IF) steel and continuous annealing system are the important events in mild steel developments for panels. Extensive work on finding the optimum mixtures of hard and soft phases to improve elongation of steels contributed to improve the crashworthiness of autobodies. Continuous annealing system also played an important role in producing these advanced high strength steels. Precipitation is used in characteristic ways which is to scavenge solute carbon and nitrogen and to prevent coarse cementite particle precipitation. It is also worth to point out that the strong collaborative activities particularly characteristic in Japan between steel manufacturers and auto companies have affected on the progress in advanced sheet steels.
Rolling theory has made remarkable progress for the last 100 years. The history of rolling theory is described in this report, comparing rolling theory with innovation of strip rolling technology. In Japan, computer control system started to be introduced to iron and steel company in 1960s. Therefore, research of rolling theory became indispensable. Before 1960, it was published mainly in Europe and America. It is said that two-dimensional rolling theory had been completed. First of all, in Japan yield stress was investigated to calculate rolling load precisely, and approximate three- dimensional analysis for deformation of rolled strip was researched to predict the distribution of rolling pressure in width direction, which made up crown and flatness of rolled strip. After that, FEM (finite element analysis method) replaced the approximate three-dimensional analysis, by which three-dimensional deformation of rolled strip could be calculated precisely. The results of these researches supported the innovation of crown and flatness control technology and the invention of many rolling mills with high functional ability for crown and flatness control. Next, the continuous strip rolling theory was completed chiefly in Japan, by which the static and dynamic characteristics of tandem strip mills could be understood. It is said that the continuous rolling technology for cold and hot strip tandem mills were not realized without the continuous strip rolling theory.