열응력 제어층을 가진 하드페이싱층의 특성분석

Abstract

The purpose of this study is to analyze characteristics of hardfacing layer with thermal stress control layer(TSCL). This study designed 4 type of finite element analysis(FEA) model to analyze heat transfer and thermal stress characteristics according to the material combination of TSCL, as well as the protruded height and the inclined angle TSCL. Materials of the hardfaced layer and the substrate were stellite 21 super alloy and STD 61 hot working tool steel, respectively. The TSCL was created by mixing of stellite 21 and STD 61. The inclined angle and protruded height of thermal stress control layer were 0o-90o and 0-2 mm, respectively. Heat transfer and thermal stress analyses were performed using a commercial software, ABAQUS V6.12. The material combination of TSCL was deduced through investing of temperature, stress distributions and strain distributions according to the material combination of TSCL. In addition, variation of temperature, stress and strain distributions in the hardfaced layer, TSCL and substrate according to the protruded height and the inclined angle of the TSCL were investigated. In order to investigate the variation of the hardness according to the wear experiment at the elevated temperature, the hardness after the wear experiment was compared to that before the wear experiment. The friction induced work hardening(FIWH) was estimated to examine the work hardening ration via the wear experiment. In addition, wear characteristics, invlundy worn width, worn depth and the morphologies of worn region, were investing added using field emission scanning electron microscope(FE-SEM). The valuation of material composition in the thickness direction was observed using low vacuum scanning electron microscope(LV-SEM). The impact resistance of the hardfaced specimen was investigated using the repeated drop impact test. From the results of the impact test, proper hardfacing material and the hardfacing thickness were estimated. Based on the above results, proper the material combination and the design of TSCL as well as the material and the thickness of the hardfaced layer were obtained.