The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

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The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous abrasion process and unravel abrasion damage formation in construction steels, i.e. carrying out scratch tests using a large indenter with different pre-loads to generate a wide pre-scratch with stable saturated work hardening and then a small indenter sliding over the pre-scratch to evaluate the abrasion resistance and observe the failure mechanism. With this approach, an extensive experimental investigation has been conducted to study the correlation of abrasion resistance and microstructural features (phase volume fraction, morphology, grain size, etc.) so as to understand the response of microstructures on abrasive wear, and eventually provide the knowledge to guide the design of high abrasion resistant steel. A promising type of microstructure with high abrasion resistance but low hardness has been proposed. In addition, a two-stage tensile strain hardening model was applied to interpret the scratch resistance under different pre-load conditions and resulting failure mechanisms. The strength coefficient K in the Hollomon equation (?=K?^n) in this model corresponds well with that of scratch resistance.