磨合表面 meaning in English

broken in surface
broken-in surface

Characterization of surface topography during running - in process with fractal parameter
磨合表面形貌变化的分形表征
A new or reconditioned engine , gearbox or rear axle needs to be “ run - in “ in order to allow the working parts to develop a special type of polished surface which can be obtained only by driving at moderate speeds without the use of full engine power
新制或大修过的发动机、变速箱或后桥装置需要磨合，以使运行部件形成特殊型式的磨合表面，这只能通过中速行驶和避免发动机满载来实现。