Internal cracks and non-metallic inclusions as root causes of casting failure of sugar mill roller shaft
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Author(s)
Type
Journal Article
Abstract
The sugar mill roller shaft is one of the critical parts of the sugar industry. It requires carefully manufacturing and testing in order to meet the stringent specification when it is used in the application under continuous fatigue and wear environment. For heavy industry, manufacturing of such heavy parts (>600mm diameter) is a challenge owing to ease of occurrence of surface/subsurface cracks, and inclusions that lead to rejection of the final product. Therefore, identification and continuous reduction of defects are inevitable. If the defect activity is controlled, it offers the possibility to extend the component (sugar mill roller) life cycle and resistance to failure. The current study aims to explore the benefits of using ultrasonic testing (UT) to avoid rejection of the shaft in heavy industry. It was made performing a rigorous evaluation of defects through destructive and nondestructive quality checks in order to detect the causes and effects of rejection. The results gathered in this study depict the macro-surface cracks and sub-surface microcracks. They contain alumina and oxide type non-metallic inclusions which led to surface/subsurface crack and ultimately the rejection of mill roller shaft. Root cause analysis (RCA) approach has highlighted the refractory lining, hot-top of the furnace and the ladle as significant causes of inclusions. The low-quality flux and refractory lining material of furnace and hot-top that were the possible causes of rejection were replaced by standard materials with better quality, applied by their standardized procedure, to prevent this problem in future production. The feedback statistics, evaluated over more than one year, indicated that the rejection rate was reduced for defective production up to 7.6%The sugar mill roller shaft is one of the critical parts of the sugar industry. It requires carefully manufacturing and testing in order to meet the stringent specification when it is used in the application under continuous fatigue and wear environment. For heavy industry, manufacturing of such heavy parts (>600mm diameter) is a challenge owing to ease of occurrence of surface/subsurface cracks, and inclusions that lead to rejection of the final product. Therefore, identification and continuous reduction of defects are inevitable. If the defect activity is controlled, it offers the possibility to extend the component (sugar mill roller) life cycle and resistance to failure. The current study aims to explore the benefits of using ultrasonic testing (UT) to avoid rejection of the shaft in heavy industry. It was made performing a rigorous evaluation of defects through destructive and nondestructive quality checks in order to detect the causes and effects of rejection. The results gathered in this study depict the macro-surface cracks and sub-surface microcracks. They contain alumina and oxide type non-metallic inclusions which led to surface/subsurface crack and ultimately the rejection of mill roller shaft. Root cause analysis (RCA) approach has highlighted the refractory lining, hot-top of the furnace and the ladle as significant causes of inclusions. The low-quality flux and refractory lining material of furnace and hot-top that were the possible causes of rejection were replaced by standard materials with better quality, applied by their standardized procedure, to prevent this problem in future production. The feedback statistics, evaluated over more than one year, indicated that the rejection rate was reduced for defective production up to 7.6%
Date Issued
2019-08-03
Date Acceptance
2019-08-01
ISSN
1996-1944
Publisher
ABM, ABC, ABPol, SBCC, SBCr, SBMM, SBPMat
Journal / Book Title
Materials
Volume
12
Issue
15
Copyright Statement
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Materials Science
root cause analysis
non-destructive testing
destructive testing
optical inspection
microscopy
rejection rate
heavy manufacturing industry
FATIGUE FAILURE
BEHAVIOR
STEEL
MICROSTRUCTURE
INITIATION
destructive testing
heavy manufacturing industry
microscopy
non-destructive testing
optical inspection
rejection rate
root cause analysis
03 Chemical Sciences
09 Engineering
Publication Status
Published
Article Number
2474
Date Publish Online
2019-08-03