Nizhniy Novgorod State Technical University (Nizhniy Novgorod, Russia):

A. A. Filippov, Cand. Eng., Associate Prof.
G. V. Pachurin, Dr. Eng., Prof., e-mail: pachuringv@mail.ru
N. A. Kuzmin, Dr. Eng., Prof., Head of the chair

Volga State University of Water Transport (Nizhniy Novgorod, Russia):
Yu. I. Matveev, Dr. Eng., Prof.

Fastening products have been widely used in modern mechanical engineering. Along with increase of their structural strength and operational reliability, it is assumed that costs will be reduced throughout the entire production chain, starting from rolling production and finishing with manufacture of finished products of the required quality. Calibrated rolled products before heading should have an optimal macro- and microstructure in order to carry out successfully further heading operations to make fastening products. Obtaining of the required grade of ferrite grain and hardness is the most important characteristic of behavior of calibrated rolled products during manufacture of parts by the method of cold heading. For this purpose it is required to select the chemical composition of steel within narrow limits (especially for carbon). Steel 38XA is widely used in production of any batches of metalware for hardened fasteners. During manufacturing process, metalware are usually subjected to quenching with tempering. Solution of the problem of production of calibrated rolled products without annealing for the structure of granular pearlite and recrystallization annealing in thermal furnaces, as well as turning of the surface of rolled products, are an actual problems. Reducing of the cost of manufactured rolled products by optimization of the structural approach to preparation of high-quality rolled metal products, which provides the functional management of its properties, is one of the possible directions to solve it. The resource-saving mode of preparation of rolled products for heading of long bolts without their subsequent quenching and tempering is off ered in the work. It is shown that the optimal combination of structure and mechanical properties after patenting of 38XA steel is achieved at compression degrees in the range 5-10 %. Subsequent increase of their reduction degree leads to increase of the tensile strength and yield strength and decrease of relative contraction and elongation.

1. Gurov V. D., Vladimirov A. G. Quality improvement for fastening products and decrease of metal consumption during manufacturing. Stal. 2005. No. 12. pp. 52–54.
2. Kulesha V. A. Features of steel production for high-quality hardware. Proceedings of the III congress of rollers. Moscow : Chermetinformatsiya, 2000. pp. 543–546.
3. Filippov A. A., Pachurin G. V., Chinenkov S. V. Formation of structural and mechanical properties of steel workpieces for reinforced screws : monograph. Nizhniy Novgorod : NGTU, 2012. 151 p.
4. Filippov A. A., Pachurin G. V., Naumov V. I., Kuzmin N. A. Low-Cost Treatment of Rolled Products Used to Make Long High-Strength Bolts. Metallurgist. 2016. Vol. 59. No. 9-10. pp. 810–815.
5. Sokolov A. A., Artyukhin V. I. Criteria of the choice of materials and process-dependant parameters for wire production for cold die forging. Metizy. 2008. No. 2(18). pp. 50–54.
6. Galkin V. V. The microstructural estimation of the distribution of the plastic deformation in metal cold-upsetting fasteners. Kuznechnoshtampovochnoe proizvodstvo. Obrabotka materialov davleniem. 2014. No. 8. pp. 11–14.
7. Amirov M. G., Lavrinenko Yu. A. Basis of automation technology for cold-upsetting production. Tutorial. Ufa : UAI, 1992. 142 p.
8. Filippov A. A., Pachurin G. V., Naumov V. I., Kuzmin N. A. Influence of surface and structural condition for quality hire for bolts. Fundamentalnye issledovaniya. 2015. No. 10(1). pp. 77–82.
9. Tomigana D., Vakimoto K., Mori T., Murakami M., Yoshimura T. Production of rolled wire with high ability to scale removal. Metizy. 2008. No. 2(18). pp. 32–42.
10. Galkin V. V. Structural-deformation assessment hardening of metal in multi-operational process of cold deformation. Uprochnyayushchie tekhnologii i pokrytiya. 2014. No. 8. pp. 13–20.
11. Moyseychik E. A. Behaviour of high stretch bolts in tension working as part of elements of steel structures, and their tendency to delayed fracturing. Vestnik MGSU. 2014. No. 11. pp. 58–67.
12. Bunatyan G. V. Fastening products. Prospects are in consolidation. Metizy. 2010. No. 1(22). pp. 12–15.
13. Zinuti A., Saro G. Wire drawing on mills. Metizy. 2003. No. 2(03). pp. 41–47.
14. Lavrinenko V. Yu. Mathematical models of the processes of cold die forging of fastening products. Metizy. 2007. No. 1. pp. 35–37.
15. Ivchenko A. V., Ambrazhey M. Yu., Machuskaya N. D., Kokashinskaya G. V. High-strength fasteners 8.8. made of thermomechanically reinforced rolled wire. Metizy. 2010. No. 1(22). pp. 58–63.
16. Filippov A. A., Pachurin G. V. Resource training to rolled steel cold heading fixing products. Mezhdunarodnyy zhurnal prikladnykh i fundamentalnykh issledovaniy. 2014. No. 8-4. pp. 23–29.