Production of coal crusher hammer heads by bi-metal casting

Kırma, Turgut
In this study, by considering different mechanical properties such as wear resistance and toughness of two different metal alloys in design and production stages, bi-metal casting technique was used for producing composite material which will be a solution for the cracking and wear problem in coal crushing hammer heads. The failure analysis of the classical hammer heads which are made from Hadfield steels (austenitic steel) showed that there are crack formations through austenitic grains and also the phase transformation from austenite to martensite is not completed until the material consumed its life. Thermal analysis is the basic technique in this study to determine the solidification conditions. By using thermocouples with a suitable set-up, the cooling curves of the materials which were used in bi-metal casting had been taken and analysed. By using these cooling curve data with a written software program which is based on Newton Thermal Analysis, the solid fraction values by time and by temperate were obtained. According to these values, the interface was investigated by changing experimental conditions and solid fractions. At the last part of the study, a new approach was tried in white cast iron production.


Characterization of ultra-fine grained steel samples produced by high pressure torsion via magnetic barkhausen noise analysis
Bayramoğlu, Sadık; Gür, Cemil Hakan; Department of Metallurgical and Materials Engineering (2009)
High Pressure Torsion (HPT) is one of the most widely used severe plastic deformation methods which enable to obtain a crack free ultra-fine grained bulk material with improved mechanical properties like increased strength and toughness. In the process, a disc shaped sample is pressed between two anvils and deformed via surface friction forces by rotating one of the anvils. The aim of this study is to nondestructively characterize the variations in the deformation uniformity of the severely deformed steel d...
Investigation of the effect of dissimilar channel angular pressing method to the mechanical and microstuctural properties of 6061 aluminum alloy sheets
Kibar, Alp Aykut; Gür, Cemil Hakan; Department of Metallurgical and Materials Engineering (2010)
Dissimilar Channel Angular Pressing (DCAP) method is an effective Severe Plastic Deformation (SPD) technique to improve the mechanical properties of sheets or strips by producing ultrafine grains. The aim of this study is to investigate the evolution of the microstructure and the improvement in mechanical properties of 6061 Al-alloy strips deformed by DCAP up to 5 passes. Mechanical properties such as hardness and strength have been observed to increase up to a certain strain level depending on the microstr...
Production and characterization of high performance al – fe – v – si alloys for elevated temperature applications
Sayılgan, Seda; Kalkanlı, Ali; Department of Metallurgical and Materials Engineering (2009)
In the present study, the powder metallurgy was evaluated as a technique to produce high performance Al – 8Fe – 1.7V – 7.9Si (wt%) alloys for elevated temperature applications and the role of powder particle size range and extrusion ratio in the microstructural and mechanical properties of the extruded alloys was investigated. For this purpose, an air atomization method was employed to produce powders of the high temperature alloy and after that the produced powders were sieved and cold compacted. The compa...
Production of in situ aluminum-titanium diboride master alloy formed by slag-metal reaction
CHANGIZI, Ahmad; Kalkanlı, Ali; SEVINC, NACİ (Elsevier BV, 2011-01-12)
Al-TiB(2) master alloys have received much attention in recent years owing to their potential as efficient grain refiners for aluminum foundry alloys. In this study, the process of production of master alloys was investigated to develop a low cost method, namely, slag-metal reaction. This method can be used to fabricate Al-TiB2 master alloy in situ from the TiO(2)-H(3)BO(3)-Na(3)AlF(6) and Al system. Since the price of the raw materials is low and the technology is simple, the processing technique appears t...
Determination of susceptibility to intergranular corrosion of uns 31803 type duplex stainless steel by electrochemical reactivation technique
Arıkan, Mehmet Emin; Doruk, Mustafa; Department of Metallurgical and Materials Engineering (2008)
In the present work the effect of isothermal ageing treatment on the microstructure and on the localized corrosion resistance of a duplex stainless steel (DSS) was investigated. Specimens taken from a hot rolled cylindrical duplex stainless bar with 22% Cr grade were solution annealed at 1050°C and then sensitization heat treatments were conducted at 650, 725 and 800°C with duration ranging from 100 to 31622 min. The microstructural changes were examined by the light optical microscopy (LOM) and scanning el...
Citation Formats
T. Kırma, “Production of coal crusher hammer heads by bi-metal casting,” M.S. - Master of Science, Middle East Technical University, 2008.