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A widely spread and most productive way to obtain finished metal articles with high structural and mechanical properties are methods of cold heading out of rolled metal, which must have a certain quality - the required plasticity, uniform structure and process parameters along the full length, as well as soundness. In conditions of fierce competition in order to improve the quality of the upset metal articles, the enterprises are forced to find reserves at all the points of the process chain for transformation of the original rolled metal. The greatest effect is achieved by the excluding of energy-consuming and labor-intensive annealing in protective gas furnaces and control of surface defects by etching or mechanical operations. This paper is presenting an economical and environment-friendly technology for structural and mechanical maintenance of high quality of rolled stock for upsetting of metal articles. The rolled steel prepared by this technology has a highly dispersed equally spaced structure without a decarburized layer with increased plasticity, which enables to reduce the number of transitions in the process of upsetting of metal articles and to increase the tools service life.

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Abstract. Hardware items are one of the products for mass consumption. Rolled metal for cold forging shall have the required ductility, uniform mechanical characteristics along the mill length, corresponding chemical composition and shall be free from internal or superficial defects. Standard mechanical characteristics have been reviewed in this document and fracture criteria of calibrated rolled steel 40Х have been calculated after its isothermal treatment at different temperatures in nitre bath and subsequent drawing with different deformation degrees. Comparison of synergy fracture criteria showed that rolled stock, treated as per the proposed conditions: bath patenting at the temperature of 400ºС and drawing with reduction rate of 5% and 10%, are more preferable, comparing to processing conditions, existing in the industry.

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The main spheres of high-strength seamless pipes application are oil and gas production sectors, as well as the defense industry. Therefore, increasing the piercing rolling efficiency, increasing the strength and durability of the tool are the main factors that ensure the smooth production of seamless pipes. The article justifies the choice of the steel grade and displays the developed manufacturing technological cycle of heavy duty mandrels used for piercing and helical rolling of seamless pipes.