TY - THES

T1 - Wear of WC/Co Cemented Carbides during Percussive Demolition

AU - Freisinger, Matthias

N1 - no embargo

PY - 2019

Y1 - 2019

N2 - This work investigates the wear behavior and mechanisms of WC/Co cemented carbides during percussive demolition. Ten different material grades, varying in regards of carbide grain size and binder content, were selected. The main objective was to evaluate different testing methods and to find correlations. Additionally, worn cemented carbide pins of the HILTI bushing tool were analyzed and these results were compared to the results of the laboratory and application tests. The cemented carbide grades were investigated concerning their grain size distribution and their mechanical properties, namely hardness and Palmqvist fracture toughness. The laboratory LCPC wear test was executed and a clear correlation to hardness was shown. The application testing was done in a fully-automated 3 axis test rig and revealed significant correlations to the laboratory testing as well as to the analyzed HILTI bushing tools. Extensive macroscopic and microscopic analysis such as Scanning Electron Microscopy were done to identify different wear mechanisms. The detected wear mechanism at the tip area was mainly impact spalling, most notably the detachment of whole WC grains and composite scale fragments. At the side area of the cemented carbide pins grinding abrasion seemed to be the dominant wear mechanism. Correlations between different WC/Co grades, sample geometries and testing methods were described in detail.

AB - This work investigates the wear behavior and mechanisms of WC/Co cemented carbides during percussive demolition. Ten different material grades, varying in regards of carbide grain size and binder content, were selected. The main objective was to evaluate different testing methods and to find correlations. Additionally, worn cemented carbide pins of the HILTI bushing tool were analyzed and these results were compared to the results of the laboratory and application tests. The cemented carbide grades were investigated concerning their grain size distribution and their mechanical properties, namely hardness and Palmqvist fracture toughness. The laboratory LCPC wear test was executed and a clear correlation to hardness was shown. The application testing was done in a fully-automated 3 axis test rig and revealed significant correlations to the laboratory testing as well as to the analyzed HILTI bushing tools. Extensive macroscopic and microscopic analysis such as Scanning Electron Microscopy were done to identify different wear mechanisms. The detected wear mechanism at the tip area was mainly impact spalling, most notably the detachment of whole WC grains and composite scale fragments. At the side area of the cemented carbide pins grinding abrasion seemed to be the dominant wear mechanism. Correlations between different WC/Co grades, sample geometries and testing methods were described in detail.

KW - wear

KW - cemented carbide

KW - Wc/Co

KW - LCPC

KW - Hartmetall

KW - WC/Co

KW - Verschleiß

KW - LCPC

M3 - Master's Thesis

ER -