Gant, A J (2006) Ball indentation fatigue of powder metallurgy steels. NPL Report. DEPC-MPE 023

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Abstract

Commercial powder metallurgy (PM) steels produced from water atomised highly alloyed powders which are pressed and gas sintered in mesh belt furnaces find ready application for use as automotive valve train components; they can be easily mass produced and require relatively little machining after being sintered/heat treated. Material specifications for PM steels for automotive applications are becoming increasingly exacting as operating conditions become more arduous and also the design lifetimes of components become longer. In the context of the latter there is at present a dearth of data on PM steels subjected to dynamic loading, and especially under relevant loading modes; hence the present study.
This NPL open report first sets the context in which these materials are used, outlines their material property requirements and briefly describes typical valve and valve seat insert compositions. An introduction to contact between a sphere and plane is also given, with both elastic and plastic deformation of the latter. Prior to conducting dynamic loading experiments, static and quasi-static material properties were measured in order to determine the dynamic loading regimes to be used. Response to dynamic loading was assessed by measuring indentation depth and examining the polished surfaces of the samples. Further examination was conducted on one selected material by sectioning vertically through indentations, polishing and then inspecting damage under the indentations by scanning electron microscopy.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	DEPC-MPE 023
Subjects:	Advanced Materials Advanced Materials > Powder Route Materials
Last Modified:	02 Feb 2018 13:15
URI:	http://eprintspublications.npl.co.uk/id/eprint/3404

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