Cracking during cold forming process of rear brake component
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Date
2008
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Abstract
The root cause for cracking of rear brake components occurred during cold forming process was investigated. Optical micrographs showed the abundance of extended inclusions with several rounded ones in the steel. SEM image revealed the fracture surface which contained many extended cavities formed by extended inclusions and dimples all indicating a ductile rupture. EDS analysis confirmed that the extended inclusions were MnS type while the rounded ones were formed as a result of Ca-treatment. The crack propagation along with inclusions was clearly observed on the polished planes and on the fracture surface. It was determined that MnS type inclusions were the root cause for the cracking phenomena. The abundance of extended MnS inclusions indicated insufficient inclusion modification through Ca-treatment and insufficient removal of these inclusions in failed steel. © 2007 Elsevier Ltd. All rights reserved.
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Brakes , Crack initiation , Crack propagation , Energy dispersive spectroscopy , Fracture , Metal forming , Optical microscopy , Rear engine automobiles , Scanning electron microscopy , Steel , Crack initiation , Crack propagation , Energy dispersive spectroscopy , Fracture , Metal forming , Optical microscopy , Rear engine automobiles , Scanning electron microscopy , Steel , Calcium treatment , Cold forming , Inclusion modification , Non-metallic inclusions , Rear brake component , Brakes