The effect of structure and elemental composition of the alloy on the results of magnetic control of the stress-strain sate of metal

The effect of changes in the chemical composition and structure of structural steel on the results of magnetic control of the stress-strain state of the metal is studied using data on the field strength of the residual magnetization. It is shown that data of magnetic control reveal changes in the stress-strain state of the metal in the region with significant changes in the structure and chemical composition. This approach is based on the control of the electrical conductivity of the metal, which is highly sensitive to changes in the structure, phase and chemical composition of structural steel. In the field of significant changes in the electrical conductivity of the metal, additional experimental studies should be carried out, including optical metallography and X-ray spectral analysis of metal samples, the results of which are analyzed in combination with the obtained data of magnetic control of the stress-strain state of the metal and thus determine the reason for the origin of the stress state in the local area of the steel product, which is important in the technical examination of steel products and elements of metal structures. It has been shown experimentally that a significant increase in the carbon content in the chemical composition of structural steel changes the electrical and magnetic parameters, but almost does not touch the magnetoelastic sensitivity of the field strength of the residual magnetization of the metal that matches theoretical considerations. We assume that this is also valid for constant and random impurities in the chemical composition of steel, if change in their content does not significantly affect the magnetoelastic sensitivity of the field strength of the residual magnetization of the metal.

1. Popov B. E., Levin E. A., Kotel’nikov V. S., et al. Magnetic inspection of stressed state and residual service life of vessels working under pressure / Bezopasn. Truda Promyshl. 2001. N 3. P. 25 – 30 [in Russian].

2. Zagidulin T. R. Application of IN-01m the mechanical strain of metal indicator in technical diagnosing and inspecting of metal structures elements / Zavod. Lab. Diagn. Mater. 2014. Vol. 80. N 9. P. 62 – 66 [in Russian].

3. Zagidulin R. V., Zagidulin T. R., Abdrachmanov R. G. Inspecting steel bolts and studs tightening effort by IN-01m the mechanical strain indicator of metal / Kontrol. Diagn. 2012. N 4. P. 15 – 23 [in Russian].

4. Zagidulin R. V. et al. Guidelines of steel items made from magnetic matherials stress-strain state inspection. — Moscow: FBU RFTsSÉ pri Minyuste Rossii, 2016. — 34 p. [in Russian].

5. GOST1497–84. Ordinary quality structural carbon steel. — Moscow: Izd-vo standartov, 1984 [in Russian].

6. GOST 10006–80. Metal pipes. Techniques of tensile tests. — Moscow: Izd-vo standartov, 1980 [in Russian].

7. Zagidulin R. V., Zagidulin T. R., Aminev A. F. Residual magnetic field strength dependence on mechanical strain value in the plane of metal / Neftegaz. Delo. 2016. Vol. 14. N 1. P. 225 – 233 [in Russian].

8. Darkov A. V., Shpiro G. S. Strength of the materials. — Moscow: Vysshaya shkola, 1989. — 624 p. [in Russian].

9. Mishin D. D. Magnetic materials. — Moscow: Vysshaya shkola, 1981. — 335 p. [in Russian].

10. Zagidulin T. R., Zagidulin R. V., Gorchakov R. K. Stress-strain state of metal evaluating magnetic technique practice in technical diagnostics and forensic inspection of steel parts and constructions / Kontrol. Diagn. 2015. N 3. P. 54 – 61 [in Russian].