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Iron-based hardfacing alloys are widely used to protect machinery equipment. A strong correlation is given between microstructure and chemical composition of welding deposit with the resulting wear behaviour. Concerning precipitation of metallurgical hard phases and synthetic added hard particles, the bonding strength of the hard phases in the metallic matrix seems to play a dominating role to obtain high wear resistance. The main objective of this study was to evaluate the wear behaviour for pure abrasion, combined impact/abrasion and high impact wear, respectively, for four different Fe-based hardfacing alloys. Tests were performed with a standard ASTM G65 dry-sand/rubber-wheel tester. An impeller-tumbler apparatus enabled investigation of impact abrasion wear tests. Additional wear tests with high impact loading were performed on a drop hammer apparatus. Fracture surface analysis was carried out after drop hammer testing and results were correlated with microstructure and interfacial bonding behaviour of precipitations in metallic matrix.

Five different carbide-matrix coatings (laser claddings) have been investigated about correlation of their specific structural parameters-especially volumetric carbide distribution-with ASTM G65 abrasion wear rates. For this study, the hardphase networks of laser claddings have been characterized by specific structural parameters, such as mean inter-particle distance, mean carbide diameter, carbide area fraction, and matrix hardness. To generate quantitative values for the inter-particle distances a particular method was developed. From regression analyses, it has become evident that wear effects arising from carbide inter-particle distance surpass the influence of carbide diameter and that of carbide fraction. Only minor contribution to abrasive wear rates is related with matrix hardness.

Carbide-matrix hardfacings reinforced with spherical and angular particles of different size and density have been investigated about correlation of their specific material parameters-especially matrix hardness and microstructure parameters-with the wear rates in continuous impact abrasion test (CIAT). For this study, 12 different hardfacings have been characterized by the quantitative metallographic method for determination of specific structural parameters, such as the mean carbide diameter, carbide area fraction, and a distribution parameter of inter-particle distances (L IPD ). Results showed the high influence of the matrix hardness on the CIAT wear resistance followed by effect of the mean particle size. The length of inter-particle distance (L IPD ) has exhibited stronger additional effect on CIAT wear rate than carbide area fraction, whereas particle form (spherical or angular) showed no significant differences.

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