New Antifriction Composite Materials Based on Tool Steel Grinding Waste

Abstract

This paper studies the effect of technological parameters to the manufacture of new effective antifriction composite materials based on 7HG2VМF tool steel grinding waste with CaF2 additions as solid lubricants in structures, having mechanical and tribological properties for high temperature friction (bearings perform at a temperature of up to 550°С, a sliding speed of 1 m/s, and a pressure up to 5.0 MPa, in air). This paper illustrates the mechanism of structure formation of the new materials and its effect on properties after using developed technological modes. Such technology can ensure a microheterogeneous fine-grained structure. The composite structure consists of a matrix based on tool steel waste and the uniformly distributed CaF2 solid lubricant. The metal matrix is pearlite and consists of an α-solid solution based on iron with hard grains of alloying elements of carbides. Such heterogeneous structure promotes a high level of antifriction properties under severe operating conditions. The behavior of CaF2 in the friction area under high temperature operating conditions has been shown. The CaF2 solid lubricant is evenly distributed over the entire friction surface. Calcium fluoride and chemical elements of the contact pair form an antifriction film, which provides self-lubricating conditions. The possibility of predicting and controlling the behavior of antifriction materials at a high temperature, by the selection of initial metal grinding waste, for ensuring the high level of functional properties, has been demonstrated. The use of grinding waste to produce effective antifriction materials makes it possible to partially solve the global problem of environmental protection.

Structure and Properties of New Antifriction Composites Based on Tool Steel Grinding Waste

“…This waste is polluted with abrasive particles from grinding wheels, such as corundum particles. Therefore, such waste is usually not used in the subsequent production cycle [6,7]. However, this steel contains valuable alloying elements (Table 1).…”

“…The authors initiated research work on the regeneration and subsequent use of some types of ferrous and non-ferrous metal-based grinding waste to obtain new bearings, and promising results were obtained [5][6][7]. Such studies are one of the first steps in using grinding metal waste to make new antifriction composites.…”

“…Thus, this study represents an innovative topic in the relevant field of knowledge, which was started by the authors of [5][6][7]. The complexities arise in grinding waste regeneration problems, development of the manufacturing processes, features of the anisotropic composites structure and their properties, the behavior of materials in the process of friction at high temperatures, loads, etc.…”

Антифрикційний Композиційний Матеріал На Основі Шліфувальних Відходів Інструментальної Сталі Для Деталей Друкарських Машин

“…Експериментальна частина з обґрунтуванням отриманих результатів Предметом дослідження є новий антифрикційний композиційний матеріал на основі шліфувальних відходів інструментальної сталі 7ХГ2ВMФ з твердим мастилом CaF 2 (Tабл. 1) [8]. Відходи інструментальної сталі 7ХГ2ВMФ утворюються на операціях шліфування штампів і є забрудненими абразивними частинками від шліфувальних кругів.…”

“…Структуру вивчали за допомогою оптичних та растрових електронних мікроскопів [8,10]; фторид кальцію в матриці визначали за допомогою скануючої електронної мікроскопії (SEM). Триботехнічні випробування проводилися на машині тертя ВMT-1 (швидкість обертання V = 700 об./хв., навантаження P до 5,0 МПа), контртіло виготовлено з литої інструментальної сталі Р18 (твердість 57−59 HRC).…”