الفهرس 
CHAPTER ONE: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Alloy steels usage in the industrial applications field witnessed massive progress over the past decades, especially in heavy and tool industries. The mechanical, chemical, and physical properties of those alloys define their specific applications. The properties of alloy steels depend on alloying elements, heat treatment, and manufacturing methods. Definitely, Alloy steels (W302, K110, M303) have a wide range of specific applications such as heavy-duty dies, punches, and molds. Mechanical properties, such as tensile strength, wear resistance, and durability must be investigated.
In this study, the effect of heat-treatment on mechanical characteristics was investigated for three different alloy steels (W302, K110, M303). The effect of hardening-tempering and annealing processes on tensile properties have been studied. Hardness was measured using a Vickers hardness (HV) tester. Also, the microstructure was explored using an SEM and EDX to explain the changes resulting from microstructure changes. Tribological behavior using pin-on-disc under different normal loads. Finally, electrochemical corrosion behavior using the potentiodynamic polarization test of alloy steels under investigation was carried out.
Alloy steel K110 after hardening experiences a remarkable increase of 91% in ultimate tensile strength (UTS). However, that also results in a significant reduction in ductility by 80%, that can be attributed to the formation of a martensitic microstructure and the presence of chromium carbides. On a similar note, ductility of hardened M303 Alloy steel dropped by 69.7% due to carbides being restrained to the grain boundaries.
The annealed steel gives a higher coefficient of friction compared to the as received and hardened alloy, while the hardened alloy gives a low level of weight loss that can be related to the highest hardness level.
High passive corrosion behavior was recorded for tested alloy steels K110, and M303. While the third alloy steel W302 showed lower passivation behavior. Also, with solution temperature increasing, active corrosion spots on specimen surfaces increase, consequently corrosion resistance decreases (high Icorr).