Установлення взаємозв'язку між кутом загострення різального інструмента й ефективністю його термофрикційного зміцнення (ТФЗ)

Abstract

У статті вирішене актуальне завдання, присвячене встановленню взаємозв’язку між кутом загострення різального інструмента та ефективністю його термофрикційного зміцнення (ТФЗ). У роботі виконана науково обґрунтована розробка технологічного комплексу оброблення сталі з використанням методу ТФЗ, що дозволило забезпечити підвищення її пове-рхневої твердості та зносостійкості удвічі-тричі. Поверхневе зміцнення досягається форму-ванням «білого шару», що підтверджено вимірюванням мікротвердості.In this article, an actual problem is solved, which is devoted to establishing the relationship between the angle of sharpening of the cutting tool and the efficiency of its thermofriction hardening (TFH). In this paper, a scientifically based for processing steel using the method of thermofrication hardening was carried out, which made it possible to provide a significant increase in their surface hardness and wear resistance by 2-3 times. The work was performed at the Department of Materials Science of the National technical university «Kharkiv polytechnic institute». The relevance of the topic and its expediency are due to the need to increase the surface strength of parts made of structural and tool steels. During the research, methods of metallographic analysis using optical microscopy were used, and durometric studies were performed. To assess the increase in the performance of steels after tfz, industrial tests were carried out on full-scale samples of woodworking tools. The study was carried out by calculation and experiment. Experimental studies were carried out on the basis of a detailed study of the influence on the final characteristics of steel of external and internal factors during their processing. In order to ensure effective hardening, TFH conditions were optimized To ensure effective hardening of the samples. The photographs of microstructures, which show changes over the cross section of the samples are presented. The presence of surface-hardened «white layer» with increased hardness is obvious, as evidenced by the prints of micro-hardness measurements. The data showed that the deformation mechanism of hardening in a short-term heating of the hardenable surface is predominant at TFH. It is also noted that the «deformed grained martensite» and ε-carbide structure is formed, the hardness of which is more than twice the hardness of the martensite structure obtained in classical hardening of the proposed steels and can be considered as a type of nanostructure. TFH is recommended for industrial use and implementation when strengthening such or similar tools and parts.