PTA‐auftragsgeschweisste WC‐NiBSi‐Schichten: Trockener und geschmierter Schwingreibverschleisstest gegen Al2O3‐oder WC11Co‐Kugeln

Tungsten carbide (WC) reinforced NiBSi coatings were deposited on mild steel S 235 by plasma transferred arc welding. The WC fraction was 60 %. A commonly used testing routine for hardfacings is ASTM G65 rubber wheel abrasion test. In practical applications, there are usually combinations of the basic wear mechanisms. The translatory oscillation test with hard counterbodies may be an additional or alternative test according to the special envisaged practical application. There is a high degree of sliding applied. For some applications such test conditions may be more suitable or are a good supplement to ASTM G65. In the present contribution WC-Co and Al2O3 balls were used as counterbodies against WC/NiBSi-coated flats. The wear tests are performed under dry conditions or engine oil lubrication. Although, the coefficient of friction (COF) is lowest under engine oil lubrication, a higher wear rate was evident on the WC-NiBSi PTA cladded overlay, if engine oil is used. In the case of sandy oils, there are sliding of the counterbody ball against the PTA coating as well as microabrasion due to moving sand particles. The fluid properties of the oil in terms of viscosity, wettability of the sand particles and its transport in the oil may be essential