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1	Friction and wear study of lean powder metallurgy steel in a lubricated sliding contact Lejonklo, Caroline January 2019 (has links) A fairly new technology used to produce metallic components is powder metallurgy (PM). Among the advantages with this technique are decreased cost of production for complex-shaped parts, new alloys are made possible, reduced end processing, less material loss, and vibrational damping effects. The downside is the number of pores created which can alter the tribological properties of the material. The focus of this report is to investigate how lean PM steel behaves under tribological contacts. Friction and wear will be investigated using a pin-on-disc setup to mimic the sliding part of a gear tooth mesh. Previous studies show that the amount of wear, and if the wear increases or decreases with increased density is dependent on the degree of porosity and the pore size. This means that the wear might be minimized by optimizing the number of pores in the material and their shape and size. The result of this study shows that the friction coefficient decreases with increasing density. The wear coefficient show signs of the same correlations but further tests are needed. The main wear comes from adhesive wear, with signs of abrasive wear. The amount of abrasive wear seems to increase with an increase in density, supporting previous studies claiming that pores can trap wear debris and decrease the number of abrasive particles in the contact. Lean steel Powder metallurgy (PM) Powder metallurgy steel (PM steel) Friction Wear Sliding contact Lubricated Porosity Tribology Adhesive wear Abrasive wear Gear Gear tooth Particles Polyalphaolefin 8 (PAO 8) Contact pressure Density Light optical microscopy (LOM) Scanning electron microscopy (SEM) Vertical svanning interferometry (VSI) Pin on disc Pin-on-disc Materials Chemistry Materialkemi Inorganic Chemistry Oorganisk kemi Other Chemistry Topics Annan kemi Other Engineering and Technologies Annan teknik Chemical Engineering Kemiteknik Materials Engineering Materialteknik
2	Influence of Surface Carbon Content on the Wear of Threaded Connections in Rock Drilling Steels Hälsing, Andreas January 2023 (has links) This thesis work was conducted at Luleå University of Technology in collaboration with Sandvik Rock Tools. The aim of the work was to determine the influence of carbon content on the wear performance in carburized steel in the dry contact interface of threaded connections between drill rods. In order to investigate this, samples of drill rod steel were carburized to three different carbon concentrations and shot peened to replicate the production process of a drill rod. The samples were wear tested by utilizing a twin-disc wear tester with one disc rotating at 100 RPM and the other at 3000 RPM to mimic the operating conditions in the threaded connection between drill rods. The results was evaluated by wear rate, surface topography, hardness as well as optical analysis by light optical microscopy and scanning electron microscopy. The results show that an increased surface carbon content provide a decrease in wear rate and an increase in hardness in the surface layer that undergo microstructural changes due to the frictional heat and contact pressure during wear testing. The primary wear mechanisms were identified as plastic deformation, adhesive scratching and material removal through delamination. carbon content wear performance carburized steel dry contact interface threaded connections drill rods samples shot peening production process twin-disc wear tester RPM operating conditions wear rate surface topography hardness optical analysis light optical microscopy scanning electron microscopy surface carbon content microstructural changes frictional heat contact pressure wear mechanisms plastic deformation adhesive scratching material removal delamination

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Friction and wear study of lean powder metallurgy steel in a lubricated sliding contact

Influence of Surface Carbon Content on the Wear of Threaded Connections in Rock Drilling Steels