近年来,全世界每年用钢七亿吨左右,许多发达国家每人每年平均用钢量高达四五百公斤。随着各国经济建设和科学技术的发展,许多国家对钢材的需求量不断增加,对钢材质量和品种要求不断提高。为了更好地满足各行各业对钢材的要求,获取更大的经 In recent years, the world uses about 700 million tons of steel each year. In many developed countries, the average annual steel consumption is as high as four or five hundred kilograms. With the development of economic construction and science and technology in various countries, the demand for steel products in many countries continues to increase, and the requirements for the quality and variety of steel products continue to increase. In order to better meet the steel requirements of all walks of life, access to larger