WEAR PROPERTIES OF FE-CUC BASED MATERIALS PRODUCED BY POWDER METALURGY
In this study, Fe-Cu-C based compact in various weight ratios of iron, copper and graphite additions to starting powder have been produced by powder metallurgy. The effects of copper and graphite additions and sliding speeds during wear tests on wear behaviours were investigated. In this study, wear tests were carried out by using pin on disc sliding wear machine with the sliding speeds of 1, 1,5 and 2 msn at the constant loads of 20N. 2000 m total sliding distance was selected. Scanning Electron Microscopy (SEM) studies were carried out on the cross section of the compacts. Worn surfaces of the samples after tests were also examined by using scanning electron microscope and energy dispersive spectroscopy (EDS) analyses. The results obtained from experimental work shows that addition of copper and graphite and sliding speed effect on wear behaviours of sintered alloyed steel materials.
Dry sliding wear behavior of molybdenum alloyed sintered steels
Abstract Powder metallurgy (PM) steels of the composition Fe–3.5% Mo–1.0% C were prepared by pressing and sintering, and the wear behavior of the steels was investigated. Through wear test combined with SEM surface analysis and metallurgical analysis of the specimens showed that the wear behavior of these steels depends on the PM processing parameters and the heat treatment as well as on the wear conditions. Specimens quenched and tempered at 500°C have high wear coefficient compared with specimens as-sintered. At sliding speeds of 1 to 5 m s−1 and normal loads of 10 to 30 N, the PM steels have low and stable wear rate. The wear mechanisms are oxidation wear, adhesive wear, abrasive wear and melt wear depending on the wear conditions.
The Analysis on Fire Smoke Exhausting Robot Vibration Based on Wavelet Transform
Belt relaxation, which affects a lot on operation reliability of the fire smoke exhausting robot, is hard to detect. In this paper, a new method for belt relaxation feature recognition based on continuous wavelet transform (CWT) is proposed, and a vibration model which simplified the robot as a 2-dof forced vibration system under harmonic excitation is established. The vibration acceleration signal has been collected using the IEPE sensor and data acquisition card, experimental results verified the accuracy of the vibration model, and weak impact signal caused by the belt relaxation was distinguished, that testify the practicability of the CWT method in belt relaxation feature recognition.