Metallurgical Failure Investigation of Railway Components

Objectives

To determine the cause of failure of railway components and suggest recommendations to mitigate such failure

Technical Details

The as received broken/damaged railway components (rail pieces, links,  wheel sets, etc.,) were examined through visual inspection, NDT, optical microscopy and SEM to determine the metallurgical nature of failure.

Various qualifying tests like tensile and hardness tests, inclusion analysis, chemical composition, etc., were carried out as per IRST-12-2009/Gr.880 and IS: 5517 standard for conformity. The received rail materials conform to the standard requirements of IRST-12-2009/Gr880 w.r.to. rails and of IS:5517 w.r.to links/screw coupling assembly.

Fatigue cracks originating from the gauge corner cracks generated at the contact surface between rail and wheel during service was observed. Hence  fracture of the rail might have occurred due to rolling contact fatigue. The damages to other components like links and wheel sets are of secondary in nature.

Achievement (Output/outcome)

Investigation report containing metallurgical assessment of damaged rail parts and cause of their failure and recommendations to mitigate the same.

Impact

To help Indian railways in formulating maintenance strategies to mitigate damages of railway components during service.

Work in progress Photos

Rail head with RCF signature	Bent axle with damaged alternator wheel