Effect of the Microstructure on the Wear Resistance of a Pearlitic Steel

Abstract

Despite the experimentation of bainitic and martensitic microstructures in wheel-rail steels, pearlitic microstructure remains dominant in railway track. The wear resistance behavior of bainitic and pearlitic microstructures is still a matter of controversy. In this study, pin-on-disc sliding wear tests were performed to analyze the effects of the microstructure on wear resistance. The AISI 1080 steel was isothermally treated at five temperatures using a dilatometer in order to obtain pearlite, bainite and martensite structures. After these treatments, bainitic and martensitic samples were tempered at 500°C. It was possible to achieve pearlitic specimens with interlamellar spacing ranging from 70 ± 4 nm to 243 ± 9 nm. It was found that the wear resistance increases with decreasing the interlamellar spacing, fine pearlite showed 30% lower mass loss than coarse pearlite. The severe deformation and dislocation accumulation in different depth from the contact surface were analyzed by electron backscattered diffraction technique. The results showed that the first 10 µm depth from the contact surface was severely deformed and a high number of random high-angle boundaries developed due to the large compressive force. Fine pearlitic structure tends to present a better wear performance when compared to bainitic or martensitic structures.

Kinetics of Isothermal Phase Transformations in Premium and Standard Rail Steels

“…Control‐cooled rails have smaller interlamellar spacing, therefore higher hardness, around 340–390 HB. [ 7,8 ]…”

“…However, there is a limit to the hardness that can be achieved with conventional pearlitic rail steels, without impairing the material toughness. [ 7,8 ] Therefore, the production of alternative microstructures such as bainitic has been considered; it can result in higher hardness than what is achieved by conventional pearlitic steels and not incur significant toughness loss. According to recent studies, bainitic steels for railway applications can reach tensile strength up to 1400 MPa and total strain between 15% and 18%.…”

Tracking the railway line in-service behaviour through metallurgical and mechanical property characterisation

“…Research has shown that by maximizing the hardness of the pearlitic structure, the wear rate is minimised in both laboratory and field tests. 9,10 It was also found that the wear resistance increases with decreasing inter-lamellar spacing. 10 Available data in the literature indicate that in the past 50 years the railways and rail manufacturers have improved rail performance by increasing hardness from 248 HB to more than 400 HB.…”

“…9,10 It was also found that the wear resistance increases with decreasing inter-lamellar spacing. 10 Available data in the literature indicate that in the past 50 years the railways and rail manufacturers have improved rail performance by increasing hardness from 248 HB to more than 400 HB. The historical path followed in the development of premium grade (high-performance) steel metallurgy is illustrated in Figure 1.…”

Relação entre a microestrutura e a resistência ao desgaste na pista de rolamento de rodas ferroviárias em suas múltiplas vidas.

“…Zener (1945) Em geral, aços com estrutura perlítica lamelar fina apresentam uma boa relação entre propriedades mecânicas, resistência ao desgaste e propriedades térmicas (BHADESHIA;HONEYCOMBE, 2006). Foi observado que quanto menor o espaçamento interlamelar da perlita, maior é a dureza e a resistência ao desgaste do material quando submetido a ensaios tribológicos de deslizamento puro (CHAVES et al, 2020).…”