Evaluation of Tensile Strength and Microhardness of Two Nickel- Chromium Based Casting Alloys with the Addition of Different Ratios Recasted Alloy Using Oxyacetylene Flame Casting Techniques

Abstract

The objective of this study is to evaluate the tensile strength and microhardness of Ni-Cr alloy by adding two different ratios of recasted alloy (25%,50%)and one controlled group (100%fresh alloy),some technicians in our country modifies the casting of Ni-Cr alloy by adding recasted alloy because of high cost of Ni-Cr and low economical state. We use two different trade mark of Ni-Cr alloy (wiron99 and maxwhiteness). According to ANSI/ADA Specification No. 14 (ISO 6871); 30 specimens were made for tensile testing for each alloy type. Another 30 specimens were made for micro-hardness testing which they were square in shape (6mm for each arm and 1mm thickness). ,after statistical analysis it was found that there were no significant differences between each sub-group for the same alloy type for tensile and micro-hardness testing specimens. Although there were a great significant differences between each alloy type.