Aerospace Technic and Technology

The subject matter of the article is the processes of monitoring and assessing the quality of austenitic chromium-nickel steels. The quality of steels and products made from them depends on the combination of physical, chemical and technological properties that are formed as a result of the phase-chemical composition and various types of processing (temperature, deformation, laser, radiation, etc.). Determination of a methodology that will supplement or replace multiple tests by measuring one parameter is highly relevant.  The goal is to find a methodology for a comprehensive assessment of mechanical and corrosion properties in one parameter, which is sensitive to external factors. It is proposed to use the specific paramagnetic susceptibility of austenite c₀ as an integral characteristic of the influence of various factors (chemical composition, melting conditions, deformation, temperature, etc.). Parameter c₀ is a characteristic of the atomic-magnetic state of austenite and a sensitive quantity to the influence of external factors. The tasks to be solved are: to formalize the correlation between the specific paramagnetic susceptibility c₀ of austenite and mechanical, corrosion properties (tensile strength s_в, conditional yield stress s_0.2, elongation d, corrosion rate K). The methods used are: a highly sensitive magnetometric method for determining the specific magnetic susceptibility X and the low content of the ferromagnetic phase of the samples of the studied steels in the initial state (before mechanical and corrosion tests). Mechanical indicators were determined in accordance with GOST 1497-84, the value of corrosion losses in chloride-containing solutions - in accordance with GOST 9.912-89.  The following results were obtained. It has been experimentally established that the tendency of changes in the mechanical and corrosion properties of steels of the AISI 321 and AISI 304 types correlates with the magnetic nature of the paramagnetic austenite matrix, which is determined by the sum of the magnetic moments of atoms per unit mass (specific magnetization). Conclusions. It is shown that the specific paramagnetic susceptibility of austenite can be used to determine the behavior (increase or decrease in mechanical and corrosion properties). It is shown that a low content of d-ferrite can also be a measure (indicator) of the behavior of these properties.

chromium-nickel steel; austenite; quality; specific magnetic susceptibility; ultimate tensile strength; yield strength; elongation; Marten-Voles deformation resistance index; corrosion

Kurylyak, V. V., Khimicheva, G. I. Zastosuvannya kvalimetry`chny`x metod dlya ocinyuvannya yakosty` udarno-navantazheny`x materiyaliv [Application of qualimetric methods for evaluation test of shock-loaded materials]. Uspixy` fizy`ky` metaliv – Progress in Physics of Metals, 2017, vol. 18, no. 2, pp. 155-175. DOI: 10.15407/ufm.18.02.155.

Snizhnoi, G. V., Rasshchupkyna, M. S. Magnetic state of the deformed austenite before and after martensite nucleation in austenitic stainless steels. Journal of Iron and Steel Research, International, 2012, vol. 19, no. 6, pp. 42-46. DOI: 10.1016/S1006-706X(12)60125-3.

Snizhnoi, G. V. Dependence of the corrosion behavior of austenitic chromium-nickel steels on the paramagnetic state of austenite. Materials science, 2013, vol. 49, no. 3, pp. 341-346.

Snizhnoi, G. V. Vply`v magnitnogo stanu austenitnoyi matry`ci na mexanichni vlasty`vosti stali AISI321 [Influence of magnetic state austenitic matrix on mechanical properties of steel AISI 321]. Aviacijno-kosmicna tehnika i tehnologia – Aerospace technic and technology, 2014, no. 7(114), pp. 105–109.

Belikov, S. B., Narivskyi, O. E. Kinety`ka korozijny`x procesiv stalej AISI 321 ta 12X18N10T u nejtral`ny`x xlory`dvmisny`x rozchy`nax ta shvy`dkist` yix koroziyi [Kinetics of steel AISI 321 and 12X18H10T corrosion process in neutral chloride containing solutions and corrosion rate]. Novi materialy` i texnologiyi v metalurgiyi ta mashy`nobuduvanni – New materials and technologies in metallurgy and mechanical engineering, 2011, no. 1, pp. 36–43.

Belikov, S. B., Narivskyi, O. E. Vply`v mexanichny`x vlasty`vostej stali AISI 304 na yiyi pitingostijkist` u xlory`dovmisny`x seredovy`shhax [Influence of mechanical properties of steel AISI 304 on its resistance to pitting in chloride containing environments]. Novi materialy` i texnologiyi v metalurgiyi ta mashy`nobuduvanni – New materials and technologies in metallurgy and mechanical engineering, 2011, no. 2, pp. 29–33.