High-temperature lubrication mechanism of alkaline borates

Like any other metalworking processes, lubrication plays a crucial role in hot metal forming (e.g. hot rolling). An effective lubrication ensures high energy efficiency, low material loss and optimal product quality. The current study investigates potential lubrication properties of alkaline borates at elevated temperature by extensive experimental work. Advanced microscopy analysis allows insights into working mechanics of the lubricants at different scales which help addressing some fundamental questions arise from the past literatures. Tribological behaviors of sodium borate were thoroughly studied by pin-on-disc testing. With a transition point around 525oC, the material exhibits exceptional lubrication performance over the range of 600oC-800oC on sliding steel pair (GCr15/mild steel). This is demonstrated by remarkable reduction in friction coefficient and wear loss volume on both contact surfaces lubricated by sodium borate compared to the unlubricated case...