Defects of the hardened layer at laser exposure

S.I Gubenko,E.V Parusov,O.V Parusov

doi:10.30838/j.pmhtm.2413.230321.7.729

Abstract

Purpose. It is necessary to investigate the influence of non-metallic inclusions on the formation of defects during laser processing. The aim of the work was to study the defects of the hardened layer of steels under laser action, associated with the presence of non-metallic inclusions. Methods. The materials for investigation were commercial steels containing different non-metallic inclusions. The specimens of different steels with preliminary polished surface were exposed to laser beaming on the installations GOS-30M and GUANTUM-16. The research methods were applied - petrography, X-ray microscopy (MS-46 Cameca) and optical microscopy (Neophot-21) to study defects and identify of inclusions. Results. It has been established that various types of defects appear on the surface and in the surface layer of steel under laser action, which are not connected and are associated with non-metallic inclusions. It is shown that non-metallic inclusions are the reason for the appearance of various kinds of defects in the hardened layer of steel products during laser processing (cracks, cavities, violation of the geometry of the hardened layer). The reasons for the appearance of defects associated with the presence of inclusions of various types are discussed. Scientific novelty. A classification of defects in the hardened layer is presented. The nature and features of the formation of defects, associated with the appearance of high-speed thermal stresses, structural inhomogeneity, as well as melting, thermal destruction and evaporation of inclusions emerging to the surface and located within the hardened layer, have been established. It is noted that the detected defects are ready-made centers of destruction of a steel product or part under conditions of static and dynamic loads, as well as contact stresses. Practical significance. It is shown that the unsatisfactory quality of the hardened layer associated with the presence of various kinds of defects near nonmetallic inclusions contributes to a decrease in the mechanical and operational characteristics of a steel product. The use of the obtained results will make it possible to develop technologies for laser processing of steels with regulated quality parameters of the hardened layer, which will prevent the formation of various kinds of defects. Keywords: steel; laser treatment; defects; cracks; hardened layer; non-metallic inclusions

Highlights

Свідоцтво – Серія ДК No 1291 від 20.03.2003 р. про внесення ДВНЗ «Придніпровська державна академія будівництва та архітектури» як суб’єкта видавничої справи до Державного реєстру видавців та поширювачів видавничої продукції
The position of the rectorate of the academy and the editorial board can do not coincide with the opinions of the authors of the magazine
According to Annex 4 to Order No 886 of the Ministry of Education and Science of Ukraine dated 02.07.2020, the journal is included in the List of scientific professional publications of Ukraine, which may publish the results of dissertations for the degree of doctor and candidate of technical sciences by specialties 192 − Construction and Civil Engineering; 132 − Materials Science

Summary

Introduction

Свідоцтво – Серія ДК No 1291 від 20.03.2003 р. про внесення ДВНЗ «Придніпровська державна академія будівництва та архітектури» як суб’єкта видавничої справи до Державного реєстру видавців та поширювачів видавничої продукції. Про внесення ДВНЗ «Придніпровська державна академія будівництва та архітектури» як суб’єкта видавничої справи до Державного реєстру видавців та поширювачів видавничої продукції. Засновник журналу: ДВНЗ «Придніпровська державна будівництва та архітектури» Наукометричні бази та електронні бібліотеки, в яких зареєстрований науковий журнал: Інформаційноаналітична система − ResearchBib; електронні бібліотеки та пошукові системи − Українські наукові журнали, Національна бібліотека України ім. РЕДАКЦIЙНА КОЛЕГIЯ: головний редактор – д-р техн.

Results

Conclusion