Research Status and Development of Low-alloy High-strength Fastener Steel

Low-alloy high-strength fastener stee which is widely used in automobiles， high-speed rail， aviation， aerospace， defense， and other fields due to its excellent mechanical properties and in line with the trend of lightweight development. In recent years， with the continuous progress of industrial technology and the increasing requirements for material performance， the development of low-alloy high-strength fastener steel has shown a new trend. It is expected that the actual practical application strength level of fasteners will exceed grade 16.8. In this paper， through the typical application of fasteners products， firstly it points out that fasteners require good mechanical properties， processing performance， and heat treatment performance. Specific performance and application environment-based evaluation is carried out to ensure safety and reliability. Secondly， this paper analyzes the history and trends of high-strength fastener steel， including high-strength fastener steel， ultra-high-strength fastener steel， and non-quenching high-strength fastener steel， and discusses the role of composition in enhancing steel properties. Then， the paper introduces the research and application of key technologies for high-strength fastener steel， focusing on the design of steel composition， control of non-metallic inclusions， resistance to delay fracture and steel manufacturing technology. The paper also discusses the impact of related content on product performance， in order to enhance the comprehensive performance of fasteners， reduce their hydrogen embrittlement sensitivity， and meet the requirements of intelligent manufacturing， it is necessary to keep the ［H］ content in steel below 1×10^-6， further reduce the size of inclusions， and control the fluctuation range of main elements in steel more precisely： <italic>w</italic>［C］±0.01%， <italic>w</italic>［Si］±0.02%， <italic>w</italic>［Mn］±0.02%， <italic>w</italic>［Mo］±0.01%， the development of low hydrogen embrittlement sensitive bainitic steel is rapidly advancing.At the same time， while environmental regulations become increasingly strict， the concept of green manufacturing and recyclability is gradually incorporated into the production of low-alloy high-strength fastener steel，and the proportion of electric furnace steel smelting and hydrogen metallurgy varieties has significantly increased..Finally， the paper looks ahead to the future of low-alloy high-strength fastener steel， which will move towards high performance， low cost， environmental protection， and intelligentization. With the progress of science and technology and changes in market demand， low-alloy high-strength fastener steel will play an important role in a wider range of fields and provide a solid material basis for the development of modern industry