Fatigue Behavior And Microstructure Examination Of Aisi D2 Trim Dies

FATIGUE BEHAVIOR AND MICROSTRUCTURE EXAMINATIONOFAISI D2 TRIM DIESbyXINCHEN WANGDecember 2013Advisor: Dr. Xin WuMajor: Mechanical EngineeringDegree: Master of ScienceAISI D2 steels are widely used as tools for forming, drawing and trimming diesdue to its high wear resistance, high compressive strength and low distortion, and itsperformance as a trim die material for cutting ultra-high strength steels (at 1GPa orabove) is investigated in this study.To simulate the production trimming process under a laboratory acceleratedfatigue condition, a trim die simulator and testing technique have been developed. In thistest 1" cubic die samples were used that offers total 12 cutting edges of 6 differentmaterial grain orientations in shearing, and with adjustable die clearance. A non-contactmetal removal volume measurement was developed to quantify the degree of fatiguedamage during cyclic loading, and the metallurgical replica method was used at differentnumber of cycles from the interrupted testing for obtaining micro-damage information.The damage rate at the cutting edge was obtained as a function of trimming processvariables, including the die material grain orientations, the loading frequency, and the