Structural and Mechanical Preparation of Rolled Products for Fasteners

Abstract

Based on the analysis of quality factors of calibrated rolled products, the structural and mechanical properties of steel 20Mn2Si for cold heading of hardware products are formed. The balance is established during the preparation of gauged bars to manufacture fasteners from it. To produce gauged bars with a diameter of 7.75 mm, a new technological flow is proposed using hot rolled products with a diameter of 8.5 mm. The proposed resource-saving technology for preparing rolled steel 20Mn2Si excludes spheroidize annealing, which reduces labor and energy costs, increases the environmental friendliness of production and operational reliability of fasteners. This eliminates the possibility of quenching cracks, the need for straightening products, the risk of thread defects and reduces the cost of manufacturing long bolts. This makes it possible to significantly reduce the process chain, reduce the cost of manufacturing fasteners and meet regulatory requirements for their mechanical properties.