Purpose The purpose of this paper is to study the wear of railway brake disc/pad in low-temperature environment and to explore the damage form of brake disc/pad materials and the law of temperature rise in braking process and its influence on friction pair material damage. Design/methodology/approach The influence of ambient temperature on tribological properties of brake materials was studied by using low-temperature environment simulation device and MM-1000 high-speed brake testing machine. The law of temperature rise in the braking process was simulated by temperature field module of COMSOL. Findings The damage of disc sample increases with the decrease of ambient temperature, and the main damage form is furrow. With the decrease of ambient temperature, pitting corrosion, wear, spalling and cracks appear successively. The maximum temperature of brake disc decreases linearly with the decrease of ambient temperature. However, when the ambient temperature is 0 in the experiment, the surface temperature of the disc will increase abnormally because of the increase of abrasive particles caused by the toughening and brittleness transformation of the material. Originality/value In this paper, through the study of train braking in low-temperature environment, the damage mechanism and law of train braking pair in low-temperature environment are found, which provide some basis for the development of high-speed railway in low-temperature environment.

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A multi-functional friction and wear testing machine was used to test the pin disk wear of high-speed railway brake friction material under different disk temperatures (20 °C, 100 °C, and 200 °C) and different ambient humidities (55%, 95%). The test results show that the change in the disk temperature and different ambient humidities have significant effects on the frictional wear performance of the high-speed railway brake material. Under the conditions of 20 °C, 100 °C and 200 °C, the instantaneous friction coefficient and wear rate of the brake material decreased as the ambient humidity increased. The different ambient humidity caused severe surface damage to the brake materials, but the damage mechanisms were dramatically different. At constant temperature, the higher the ambient humidity, the lower the maximum equilibrium temperature of the disc.

Purpose The purpose of this paper is to study the influence of braking speed at –20 °C on the wear property of high-speed railway braking materials and the temperature also stress analyses of brake disc friction surface. Design/methodology/approach Friction brake tester was used to simulate the wear test of high-speed railway braking materials at diverse braking speeds (2,100, 2,400, 2,700 and 3,000 rad/min) at –20 °C and the stress and temperature analyses of brake disc friction surface were carried out by COMSOL. Findings Compared with 20°C, there is initial stress of brake disc friction surface before brake starting; also, the maximum wear depth is larger at –20°C. Besides, at –20 °C, with the rising of braking speed, the graphite particles on the friction surface of brake pad significantly reduce. And scratches and cracks are formed on brake pad friction surface. Besides, the abrasive wear, adhesive wear and thermal cracks of brake disc friction surface are aggravated. Moreover, the maximal worn depth also increase. Meanwhile, the highest temperature and the maximum thermal stress of brake disc friction surface both raise. Furthermore, the temperature and thermal stress gradients at radial direction of brake disc friction surface aggrandize, which makes the thermal cracks on brake disc friction surface further exacerbated. Research limitations/implications In this paper, the wear property of the high-speed railway braking materials is studied by combining experiment and simulation. However, due to the low-speed traveling of high-speed railway was mainly studied in this paper, there may be no comprehensive simulation of the real running condition of high-speed railway. At the same time, the working condition of low-temperature environment cannot be completely simulated and controlled. Practical implications The research results of this paper provide a basic instruction for other researchers and also provide an important reference for relevant personnel to choose the braking speed of high-speed railway at –20 °C. Social implications The research of this paper provides a brick for the study of high-speed railway braking materials and also provides some references for the safe service of trains in low-temperature environment. Originality/value This paper studied the wear property and carried out the simulation analysis of braking materials at –20 °C at diverse braking speed. The research findings provide an important reference for the selection of braking speed of high-speed railway at –20 °C.

The pin on the disc friction tester was used to conduct the intermittent braking testing of train brake materials with a low-temperature environment simulation device at temperatures 20 °C, 0 °C, −10 °C, −20 °C, and −30 °C. The results show that intermittent braking presents different wear characteristics of braking materials at low temperatures. Under different ambient temperature conditions, the most volatile friction coefficient caused by intermittent braking happens at 0 °C, and the wear rate of brake materials reaches its maximum at 0 °C. The wear surface morphology of the brake pad material mainly includes scratches, furrows, adhesions, and abscission pits, while the surface of the brake disc material was dominated by scratches, furrows, and adhesions. With the decrease in temperature, the adhesion damage of the brake pad/disc material increases. At 0 °C, the brake pad material has crack damage.