Novel Tensile Test Jig and Mechanical Properties of WC-Co Synthesized by SHIP and HIP Process

Abstract

Tungsten carbide-cobalt (WC-Co) alloys have various mechanical properties according to their Co content and manufacturing method. High-strength materials such as WC-Co alloys are usually manufactured using various sintering methods. In this study, WC-Co was compared according to the Co content and manufacturing method using the sinter-hot isostatic pressing process. Furthermore, an additional test was performed to investigate the effect of post-hot isostatic pressing (HIP) treatment on the mechanical properties. To compare tensile strength, threaded end and shoulder end specimens are generally applied in axial tensile testing with hard metals. However, it is extremely difficult to shape WC-Co by machining. A tensile testing jig for a shoulder end specimen is, therefore, proposed. Tensile tests were conducted using the proposed jig, and microstructure, hardness, and impact tests were carried out to compare the mechanical properties. The microstructure evolution was obtained by decreasing the Co content and applying the HIP treatment, resulting in changes in Young’s modulus and strength. The results indicated that the proposed jig of the axial tensile test could be applied to the extremely hard WC-Co, and the mechanical properties of WC-Co could be modified by the Co content and HIP treatment control.

Keywords

• WC-Co
• sinter-HIP
• high-strength steel
• tensile test
• jig