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Lecture

Mechanical Assessment of Hypo- And Hyper- Eutectic Chromium Carbide Hard Facing Steel Grades

Tuesday (27.09.2016)
17:30 - 17:45
Part of:


Wear resistance and mechanical performance of materials used in cement plant construction and also some other potentially usable construction materials was studied and investigated. The studied materials are chromium carbide hard-facing alloys of hypo- and hype- eutectic steel grades. The abrasion resistance and mechanical performance of three selected hard-facing alloy grades reinforced with primary chromium carbides, complex carbides and tungsten carbides were studied. The hard-facing alloys were deposited onto ASTM A36 carbon steel plates. The abrasion tests were carried out in a dry sand–rubber wheel abrasion machine according to the procedure A of ASTM G65 standard, as well as hardness, bending and impact tests measurements. Microstructure characterization and surface analysis were made using optical and scanning electron microscopy. The results showed that the wear resistance is determined by the size, shape, distribution and chemical composition of the carbides, as well as by the matrix microstructure, highest wear resistance was obtained from tungsten carbides chromium tungsten carbides presence in a fishbone shape type of M?C and presence of excessive stress cracks which causes law bending ability while for chromium carbides and Chromium Molybdenum carbide the presence of primary carbides M?C? and formation of complex carbides Mo?C in an austenite eutectic matrix offered accepted bending strength and wear resistance approximately 14 times more than for carbon steel and 7 times more than for alloyed quenched and tempered steel. Flow simulation study was done using Solid Works Flow simulation dynamics to understand the raw material flow behavior inside the production line. An elbow joint between the raw mill and cyclones was selected for this study. Pressure and sliding velocity distribution results explained and showed that there is high erosive wear at the upper cross sections than the lower section specially at changing direction angles. According to the simulation results chromium carbide used for constructing the cross section undergoes abrasion wear while Chromium Molybdenum carbide is used for the cross section the joint undergoes erosive and impact wear. Cost analysis study was conducted to determine the life time cost for each material as a basis for selecting the best optimum material which gives economical savings for a 10-year operating period taking in consideration investments cost, maintenance cost, material cost and service life time. Results showed that on long run investment chromium carbide and Chromium Molybdenum carbide have the optimum economical saving by 85 % guaranteed for 10 years compared to the traditional material used in cement plant.

Speaker:
Prof. Dr. Bakr Rabeeh
German University in Cairo
Additional Authors:
  • Prof. Dr. Yasser Fouad
    German University in Cairo
  • Zeyad S. Abd El Azim
    German University in Cairo