TESTING 1-2-3
The Impact of Weld Repair On Aluminum Sand Castings
Researchers investigate the accepted belief that weld repair does not affect the mechanical properties of an E357 sand casting. A MODERN CASTING STAFF REPORT
holes, isolated porosity and cosmetic mechanical damage. Purchase orders or similar documents often permit repair welding of these minor defects. In addition, other governing specifica- tions may permit repair welding. Metalcasters have thought prop-
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ADDING IT ALL UP Breaking down the latest research is as easy as 1-2-3.
“Effect of Weld Repair on Static and Dynamic Tensile Properties of E357-T6 Sand Castings” Gerald Gegel, Material & Process Consultancy, Morton, Ill.; Dan Hoefert, Eck Industries Inc., Manitowoc, Wis.; Joseph Hirvela, Consolidated Precision Products Corp., Minneapolis; Randy Oeh- rlein, Carley Foundry, Blaine, Minn.
Background—Proper weld repair is thought to have little or no effect on a casting’s final mechanical and physical properties. This study was designed to consolidate industry best practices for the in-process weld repair of aluminum-silicon hypoeutectic alloys, develop mechanical properties to demonstrate the efficacy of the practice, and develop statistical data that facilitates acceptance of weld practice. Procedure—Artificial “defects” were machined into standardized E357-T6 test plates and then repair welded using a standardized procedure. Test specimens containing full and partial penetration welds then were tested to determine tensile and fatigue properties. Results and Conclusions—Repair welding with the process parameters used for this study had no detrimental effects on either tensile or fatigue properties of E357-T6 sand castings. The study appears to support the conjecture that properly accomplished welding is appropriate for weld repair of cosmetic surface defects and does not affect static and dynamic tensile properties of the casting. Additional research is needed to deter- mine if this is true for other cast aluminum alloys.
tructurally sound castings may contain minor surface defects such as blow holes, misruns, mold-wash holes, flash holes, sand
erly accomplished weld repair has little or no effect on a casting’s final mechanical properties. However, some end users and government agencies do not accept this axiom and either don’t accept weld repair or require design properties be “knocked down” to permit their use with a consequent increase in the cost of using castings. A research team investigated this widely accepted assumption in a study designed to either validate or refute the claim. Te findings were published
in the paper, “Effect of Weld Repair on Static and Dynamic Tensile Properties of E357-T6 Sand Castings,” by Gerald Gegel, Material & Process Consul- tancy, Morton, Ill.; Dan Hoefert, Eck Industries Inc., Manitowoc, Wis.; Joseph Hirvela, Consolidated Preci- sion Products Corp., Minneapolis; and Randy Oehrlein, Carley Foundry, Blaine, Minn., which was presented at the 2013 AFS Metalcasting Congress. While the study focused solely on
E357 castings, its conclusions sug- gest similar results would be expected for other weldable aluminum casting alloys. Additional testing would be necessary to validate any assump- tions for performance other than that covered in this research.
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Background In-process repair welding
is an economical means to repair localized cosmetic or processing damage. Individual
studies show proper heat treatment and inspection do not compromise the structural integrity of cast alumi- num. Defining the best practices for in-process welding provides a tool that may result in quality castings that can save time and cost, especially during short production runs. As part of a larger program to establish statistically validated mechanical properties for E357-T6 sand castings, this weld repair study was designed to consolidate industry best practices to establish an AFS Recommended Practice for the in-process weld repair of aluminum- silicon hypoeutectic alloys, develop
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