Abstract
Introduction. On the example of a motor grader knife, ways of increasing the reliability of road construction machines (RCM) operation are evaluated. For this purpose, the analysis of force effects nature on the working body of the RCM is carried out and its design features are highlighted (the presence of a welded joint). Based on the analysis, the range of characteristics necessary for making a decision on the possibility of replacement the material of the RCM working body is determined. Additionally, its thermocyclic treatment (TCT) is carried out. Experimental studies of the effect of this thermal impact type on the structure and properties of steels are described.Materials and methods. With the help of metallographic analysis, the author investigates the influence of the number of thermal effects cycles on the grain size and the complex of various materials physical and mechanical characteristics of road construction machines working body at various stages of the thermocyclic treatment.Results. It is determined that an increase in the level of the investigated steels physical and mechanical characteristics is possible through the use of TCT due to the obtaining of a fine-grained metal structure. The dependences of the main physical and mechanical characteristics of the investigated steels (ultimate strength and yield strength) on the number of thermal effects cycles are considered. Correlation relationships are selected to describe these dependencies. The relationship between the yield strength and ultimate strength of 09G2S and 30MnB5 steels and the grain size is considered. In addition, studies of the steels fatigue characteristics are carried out; data on determining the microhardness are presented for the welded joint. For various operating temperatures, fractographic studies are carried out on samples after cyclic loading.Discussion and conclusion. Based on a comparative analysis of the complex of physical and mechanical characteristics, the author made a conclusion about the possibility of replacing steel 09G2S with steel 30MnB5.
Highlights
On the example of a motor grader knife, ways of increasing the reliability of road construction machines (RCM) operation are evaluated
Сталь марки 09Г2С с увеличением частоты не обнаружены
Maksimov (Saint-Petersburg) – Dr of Sci. Ec., Professor of Technological Machines
Summary
Объектом исследований были выбраны широко применяемые в дорожно-строительных машинах стали 09Г2С и 30MnB5. Цель исследований заключалась в сравнительном анализе микроструктуры и комплекса физико-механических характеристик данных сталей и их сварных соединений после термоциклической обработки для определения возможности замены стали 09Г2С на сталь 30MnB5. Данный микроскоп позволяет получать СЭМ-изображения и проводить анализ элементного состава в реальном времени в одном окне программного обеспечения TESCAN EssenceTM, что значительно упрощает получение данных как о морфологии поверхности образца, так и о его локальном элементом составе и делает СЭМ TESCAN VEGA эффективным аналитическим решением для проведения регулярного контроля качества материалов, анализа отказов и различных лабораторных исследований. В таблицу 2 сведены результаты испытаний на растяжение (предел текучести σ0,2, предел прочности σb) и по определению среднего размера зерна d исследуемых сталей после термоциклической обработки. Рассмотрим зависимости предела текучести и предела прочности исследуемых сталей от числа циклов термической обработки.
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