Investigation of a failed circular sawmill blade structures

摘要

AbstractThe engineering materials fracture is an undesirable event due to human lives that could be in jeopardy, economic loss, and the negative interference with the availability of products and services. Sawmill blade performance depends on many factors ranging from the structure of the materials of the blade, applied load, operating conditions and the target body to cut. A sawmill blade cutting tooth must be of high carbide material for longer life span in service. A portion of a failed sawmill blade for cutting wood was examined for chemical composition. The X-ray characterization was carried out using diffractometer (XRD) and scanning electron microscopy (SEM) for the proper understanding of the blade phase composition and structure. The results obtained were compared with the standard steel blade properties to predict reasons for the failure apart from the torsion effects on the materials. The carbon content of the blade is 0.66% medium carbon steel class. The carbon content of the failed blade was less compared to that of the standard (0.8% C and above). Carburization treatment was recommended for improvement of the sawmill blade performance based on the material composition. The failure of small-sized component needs prevention to avoid catastrophic destruction and consequently injury or death that may cause expensive lawsuits.Highlights?The carbon content of the blade is 0.66% of medium carbon steel class.?The composition was less to the standard that supposed to be 0.8% C and above.?Different plane orientations of ferrite, martensite and iron-carbide found present.?Different crystal structure & orientation caused the fatigue failure of the blade.?Angle of draw of the plank exerted angular force on the blade.]]>