Recently domestic heavy industries, shipbuilding companies become to be interested in a developing long life cycle for the vessel and marine structures with effective maintenance rate and endurance properly. Especially, bearing requires special bonding strength control because they tend to be exposed to extreme harsh environment during engine operation. Most of the main bearing are bonded with white metal through centrifugal casting method so far for optimized a mechanical and chemical property and condition for engine operation.
However, bearing manufacturers have to improve their manufacturing process of white metal bearing satisfying customer's delivery requirement and also more economical way. Currently welding method for matching those requirements is underdeveloped and it can make shorter process steps of manufacturing white metal bearing; however, as a special character of welding method, the soundness of bonding layer between white metal and base metal needs to be verified by specific testing and inspection methods.
In this study, mainly the improvement of testing and inspection methods which has not been applied to engine makers' requirement yet are focused. In addition, this study intends to give a direction of optimized testing method to improve the detecting level of internal indications as void and crack.
At first, Charmel test according to ISO4386-2 is chosen to check bonding strength of white metal lining. Additionally, micro structure, metallic composition are implemented to refine the characteristic of internal condition of the layer of white metal and base metal. Finally Non Destructive Testing, Ultrasonic Testing is conducted with additional testing method as Dual beam testing method to detect sub-surface indiction in the white metal which is difficult to be found by straight beam itself.
Based on above mentioned test results, additional testing method of Dual beam is applied as desirable method.