Novolipetsk Steel Plant, Lipetsk, Russia

V. V. Naumenko, Cand. Eng., Program Manager of the Directorate for Research and Development of New Products, e-mail: naumenkovi@mail.ru
D. A. Ringinen, Cand. Eng., Head of Expert Direction of the Directorate for Research and Development of New Products
A. S. Rogatovsky, Engineer of the Directorate for Research and Development of New Products

Novolipetsk Steel Plant, Lipetsk, Russia¹ ; Lipetsk State Technical University, Lipetsk, Russia²

O. A. Kurganova, Postgraduate Student², Senior Engineer of the Directorate for Research and Development of New Products¹

I. P. Bardin Central Scientific Research Institute of Ferrous Metallurgy, Moscow, Russia
M. Yu. Matrosov, Cand. Eng., Deputy Director of the Institute of Quality Steels

The paper presents the results of physical modeling in laboratory conditions of temperature regimes of controlled rolling, accelerated cooling and simulated rolling in the conditions of mill DUO 300 on samples from industrial slab, produced at PJSC “NLMK”, made of steel grade 30G2 to obtain in the metal strength properties corresponding to strength group N80 (tensile strength over 689 MPa, yield strength in the range of 552-689 MPa, relative elongation not less than 19 %) according to GOST 53366 / API 5CT. The evaluation of microstructure using optical microscopy, mechanical properties in static tensile tests and dynamic impact bending tests of laboratory metal rolled under different temperature regimes of the end of rolling and simulated rolling has been carried out. Recommendations on the content of chemical elements in steel to meet the requirements of regulatory and technical documentation of various manufacturers of electric-welded pipes were issued, the optimum temperature parameters for industrial testing in conditions of mill 2000 of PJSC “NLMK” were determined to ensure the strength group N80 on the basis of grade 30G2 without a significant increase in the cost of alloying.

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