International Journal of Rock Mechanics & Mining Sciences 40 (2003) 405–414 Technical Note Statisticalandmicroscopicinvestigationofdiscsegmentwearrelated to sawing Ankara andesites A.S. Eyuboglu*, Y. Ozcelik, S. Kulaksiz, I.C. Engin Department of Mining Engineering, Hacettepe University, Beytepe, Ankara 06532, Turkey Accepted 9 December 2002 1. Introduction Despite the advancement in the technology, and the introductionofmanysyntheticmaterials,hardrockstill keeps its vital importance in daily constructive and decorative consumption. The hard rock processing sector has shown a rapid development since 1930. Turkey has also been affected by this development and many numbers of hard rock processing factories have beenestablishedinthelast15years.Theimportofbasic machines,equipmentandconsumablesinthesefactories constitutes a major economic problem in this sector. Disc consumption is the most important economic expenditure during the processing of hard rocks. Unsuitable manufacturing of discs and inappropriate adjustment of machine parameters to the rocks to be cut, causes the discs to deteriorate rapidly, leading to eventual economic loss [1]. The circular diamond saw blade contains a steel core whichhasdiamondimpregnatedsegmentsbrazedonthe periphery(Fig.1).Thesegments(metalbonds)havetwo basicfunctions.Thesearetoholdthediamondtightand to erode at a rate compatible with the diamond loss. Duetoalargevarietyofsawingconditionsmanymetal matrixcompositionsareingeneraluse.Bondsbasedon copper, various bronze compositions, and on cobalt, tungsten, and tungsten carbide as well as combinations thereofcoverawiderangeofstonesawingapplications. Sometimessmalladditionsofiron,nickel,etc.aremade toaidthemanufacturingprocessorinthebeliefthatthe addition improves diamond retention or matrix wear properties; however, the complexity of compositions encounteredinproductionpractice,whichinsamecases comprisesevencomponents,makesascientificapproach to the total problem extremely difficult or even impossible [2]. In general, many factors affect the stone cutting by a circularsawblade.Thesefactorscanbewritteninthree groups (as shown in Table 1) [3]. Thefirstimportantfactoristheengineeringproperties of the material. The clue of the suitable values of parameters to reach the effective result is constant parameters. The physico-mechanical, mineralogical and petrographical properties must be analyzed before the sawing test and these results must be used in the producing part of the segment and saw blade. The performance of the sawing with a disc cutter is affected bydiamondtype,thesizeofdiamond,theconcentration of diamond and the properties of the metal bond (matrix). In general, the diamond crystals must have sufficent strengthtowithstandtherepeatedcuttingforcesduring thegranitesawingprocess.Ifthediamondistooweakin strength, it will easily produce macro-cracks and crushed particles. It will also cause the blade to act hard so that possibly glazing will occur. Conservely, if the diamond has very high strength and toughness, it will be difficult to fracture it to produce new cutting pointsandedges.Inaddition,itwillbepolishedtogive the blade a glazed appearance. The choice of the optimumdiamondtypeforagivenapplicationdepends on many factors, such as the stone type, the cutting conditions, the type and the quality of the machine, etc. [4]. LuoandLiao [4] reportthatvariousstudieshavebeen conductedtoinvestigatetheeffectsofthediamondtype and size of wear and sawability in the processing of stonewithdiamondsaw-blades.JenningsandWright [5] stated that hard materials usually require a smaller size diamond than do softer stones because the load per particle is not sufficiently high and greater clearence is required for swarf. Conversely, if large diamond grits are used on hard materials, the penetration of the *Correspondingauthor.DepartmentofAppliedScience,University ofArkansasatLittleRock,Arkansas72204,USA.Fax:+1-501-569- 8020. E-mail address: aseyuboglu@ualr.edu (A.S. Eyuboglu). 1365-1609/03/$-see front matter r 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S1365-1609(03)00002-9