Rolled Metal Structure Resource Saving Preparation for Long-Length Hardened Bolt Upsetting

Abstract

Along with design factors, reliability of the work-pieces for machines and mechanisms is a function of the structure and the properties of the implied materials; these properties depend significantly on the kind and the mode of the process treatment. Taking into account hardwares production, along with the increased structural integrity and service reliability, a reduction of costs starts from the rolled metal production to manufacturing of the finished parts of required quality. This is particularly relevant under the conditions of mass-production. The article presents a resource saving process flow for a 40X rolled steel, developed as a result of studying the influence of thermal and plastic treatment modes on its structural and mechanical properties. The purpose of the new process flow is the production of hardened bolts, involving drawing and isothermal treatment, but excluding the volume quenching and tempering. Spheroidizing annealing is substituted with an isothermal operation, patenting, which allows to reduce energy costs and to increase environmental compatibility of production and service reliability of bolted items. This makes it possible to shorten the process chain and to reduce the cost of long-length bolts production. The method prevents any potential quench cracking, eliminates the necessity for work-pieces' straightening, decreases the risk of thread defects.