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近代工业的发展对加工不锈钢、超高强度钢、高温合金和钛合金时用的刀具材料提出了更高的要求。而目前使用的一般高速钢已经难以胜任。寻找硬度更高、韧性和耐磨性比较好的新型高速钢已成为当务之急。在以传统方法制遣的高速钢材料中,由于钢锭凝固时冷却缓慢而引起的碳化物严重偏析和粗晶结构明显地损害工具的性能,例如材料硬度不均、热处理变形、可磨削性差、刃口韧性不足等。并且合金元素含量越高,偏析越严重,甚至难以制成工具。因此,多年来人们一直在寻求克服这种组织偏析的方法。自七十年代以来,粉末冶金已被认为是消除偏析的最好途径,并得到了大量发展。粉末冶金高速钢就是将雾化高速钢粉末,经过成型、烧结、热加工等工序,制成高速钢坯材或制品。由于粉末是用惰性气体或高压水雾化高速钢熔液而获得的,液滴以10~3～10~5度/秒快速冷凝,因而晶粒细小,碳化物也细小而且弥散,不存在偏析现象(一颗粉末重量相当于一般钢锭的百亿分之一)。因此受到世界上许多先进工业国家的重视。例如,最早投入大量生产的瑞典Uddeholm公司采用了ASEA-STORA方法,能生产出φ380×1600毫米,重量达到1.8吨的粉末高速钢钢锭,年产量为3600吨;美国的坩埚材料研究中心专门研究了具有特殊性能的一系列超硬粉末高速钢,效果显著。据初步统计,目前国外研究和生产粉末高速钢的单位不少于14个国家,74个公司。几年来的生产与试验表明,粉末高速钢的主要优点是:(1)淬硬后可磨削性好;(2)使用时韧性充分;(3)热处理时碳化物溶解迅速,不易过热,不易变形;(4)硬度沿截面分布均匀,(5)能生产传统方法不能生产的高合金工具钢以及高速钢-硬质碳化物复合工具材料。
Modern industrial development of stainless steel, ultra-high strength steel, high temperature alloys and titanium alloy used in cutting tool materials put forward higher requirements. The current high-speed steel used in general has been difficult to do. Looking for higher hardness, good toughness and wear resistance of new high-speed steel has become a top priority. In the conventional high-speed steel materials, the severe segregation of carbides and the coarse-grained structure caused by the slow cooling of the steel ingot during solidification significantly impair the performance of tools such as uneven hardness of the material, heat treatment deformation, poor grindability, Cutting edge toughness and less. And the higher the content of alloying elements, the more serious segregation, and even difficult to make tools. Therefore, people have been looking for ways to overcome this segregation of tissue over the years. Since the 1970s, powder metallurgy has been considered the best way to eliminate segregation and has been greatly developed. Powder metallurgy high-speed steel is atomized high-speed steel powder, after forming, sintering, thermal processing and other processes, made of high-speed steel billets or products. Since the powder is obtained by atomizing a high-speed steel melt with inert gas or high-pressure water, the droplets rapidly condense at 10 to 3 to 10 to 5 degrees per second, so that the crystal grains are fine and the carbide is fine and dispersed with no segregation Phenomenon (a powder weight equivalent to one billionth of the general ingot). It is therefore valued by many advanced industrial countries in the world. For example, Uddeholm, Sweden’s first mass-produced unit, used the ASEA-STORA method to produce powdery HSS ingots measuring 380 x 1600 mm and weighing 1.8 tonnes with an annual capacity of 3,600 tonnes. The US Crucible Material Research Center With a special series of super-hard powder high-speed steel, the effect is significant. According to preliminary statistics, the current foreign research and production of powder high-speed steel unit not less than 14 countries, 74 companies. Over the past few years of production and testing showed that the main advantages of powder high-speed steel are: (1) hardenability and good grinding; (2) the use of toughness sufficient; (3) heat treatment carbides dissolve rapidly, not easy to overheat, not easy Deformation; (4) uniform distribution of hardness along the cross-section, (5) can produce high-alloy tool steel and high-speed steel - hard carbide composite tool material that traditional methods can not produce.