yildiz technical university

ICAME2016 2ND INTERNATIONAL CONFERENCE ON ADVANCES IN MECHANICAL ENGINEERING

PROCEEDINGS BOOK

ORHAN ÇAKIR “MACHINING OF HADFIELD STEEL : AN OVERVIEW”

pp:227-232 10-13 MAY, 2016

YILDIZ TECHNICAL UNIVERSITY

ISTANBUL, TURKEY 1

CONFERENCE ON ADVANCES IN MECHANICAL ENGINEERING ISTANBUL 2016 – ICAME2016 11-13 May 2016, Yildiz Technical University, Istanbul, Turkey

MACHINING OF HADFIELD STEEL : AN OVERVIEW *Orhan Çakır Yildiz Technical University Besiktas, Istanbul, Turkey Keywords: Machining, Hadfield steel, machining parameters, tool life, surface roughness * Corresponding author:, Phone: +90 212 3832750, Fax: +90 212 3833024 E-mail address: [email protected]

ABSTRACT

property of the invented material contained 2.5-7% manganese (Mn) with keeping carbon (C) level low (around 0.40% C) [58]. The material contains about 0.7-1.4% C and 6-25% Mn. Its unique properties such as high toughness, high wear resistance, low thermal conductivity, non-magnetic and workhardening make the material very interesting from material science and mechanical engineering points of view. The Hadfield steel is extensively selected to produce various components such as rock crushers, grinding mills, dredge buckets, power shovel buckets and teeth pumps for gravel and rocks for different industries like earthmoving, mining, quarrying, oil well drilling, steel making, transport, nuclear fusion reactors, etc. It is also used in sprockets, pinions, gears, wheels, conveyor chains, wear plates and shoes etc. due to resist metal-to-metal wear [9-13]. Its valuable properties, however, restrict the industrial application of Hadfield steel because the material is generally known as difficult-to-machine. Very limited studies have been carried out to investigate machining of Hadfield steel. Therefore it is noticed that there is a wide gap in this area; as a result, the present study is aimed to provide scientific information from limited research studies to cover this gap. The detail literature review has been carried out to find out firstly the mechanical properties of Hadfield steel and then its machining characteristics.

Machining is the most extensively applied manufacturing technology when high dimensional accuracy and surface quality are required. This method is capable to shape any material from plastics to super alloys. Hadfield Steel is wellknown difficult-to machine materials due its chemical composition containing high manganese. It was invented by R.A. Hadfield in 1882 while searching new material which is harder, stronger and tougher than steel. Hadfield Steel, which is also known as austenitic stainless steel, has found various industrial applications like railroads, crusher jaws and cones, impact hammers production where dynamic loads are the major factor. Machining of Hadfield Steel is very attractive subject due to mechanical properties. In this study, machining characteristics of Hadfield Steel is searched in detail after brief information about this material. The paper aims to examine studies based on machining parameters and overview them to find solutions such as gaining optimum machining conditions in the machining of Hadfield Steel. INTRODUCTION Machining processes which remove unwanted material, called chip, from the workpiece by shearing action using a wedge-shaped tool, are the most extensively used manufacturing process. The processes such as turning, milling, drilling, shaping etc. are widely applied to produce machine components with required geometry and dimensional accuracy [1-4]. Hadfield steel which is also known as high manganese steel or austenitic manganese steel was invented by Robert Abbott Hadfield (1858-1940) in 1882. Hadfield patented his researches in the USA as well as in the UK. He mentioned in his patents that the new material was harder, stronger, denser and tougher than steel. It was also noticed that self-hardening

HADFIELD STEEL From the invention of Hadfield steel to nowadays industrial application, the material has been extensively developed and various new chemical combinations have been tried to improve properties such as mechanical, physical and machinability. Some of these developments have been patented particularly in the USA [4-6,14-30]. The most common chemical element combinations are listed in Table 1 [31]. 2

Conference Paper

The main elements in Hadfield steel are obviously carbon (C) and manganese (Mn), the combination of these two elements influences most of mechanical properties and machinability characteristics of Hadfield steel. The amount of carbon is generally around 0.7-1.4%; the level of 1%C makes the material higher tensile strength and yield strength. Less C content (lower than 1%C reduces tensile and yield strengths. The amount of C can be higher than 1.2% if the abrasion resistance of material is expected higher. High C content (above 1.4%) is seldom used due to low austenitic structure that causes low strength and ductility [31].

noticed from Table 1. The additions of Cr and Mo with 1.15%C amount increase yield strength. Moreover, Cr only addition increases the wear resistance and raises yield and tensile strength. The amount of Cr in Hadfield steel should is kept around 1.5-2.5% for ASTM A 128 grade C material, Others do not have any Cr content [14,15,25,31]. Cr also helps increasing machinability of Hadfield steel and stabilizes the austenitic structure. However, the excess of Cr addition extremely raises the strength of Hadfield steel which adversely influences the machinability [25]. Mo addition improves strength of the austenite matrix, toughness and resistance to casting cracks, the level of Mo content is around 0.5-2%. The minimum level of Mo amount should not be less than 0.01%, otherwise the machinability property decreases [25]. Nickel (Ni) stabilizes the austenitic structure because it remains solid. It increases ductility, decreases yield strength and lowers abrasion resistance of the material. As a result, reduction of yield strength improves machinability of Hadfield steel [25,31]. Nitrogen is another austenite stabilizing element and its addition increases strength and provides good ductility at high temperature in Hadfield steel. However, the amount of nitrogen should be only about 0.01%, excess amount could cause gas porosity in casting [25,31]. Vanadium is helpful to obtain higher yield strength, but lowers ductility property [25,31]. Niobium also has positive effect on yield strength, however the additions of both elements provide no negative effect on machinability due to high strength. The amounts of vanadium and niobium should be not less than about 0.01% each. Higher contents of these elements decrease machinability of Hadfield steel [25]. Bismuth is added to Hadfield steel that improves machinability, particularly with combination of higher Mn amount is used (more than 13% Mn) [31]. Titanium and zirconium have no direct influence on strength and machinability of the material within the ranges around 0.005-0.5% for titanium and 0.01-1.0%for zirconium [25,31]. Calcium serves as a deoxidizer or desulfurizer and improves machinability; the suggested upper limit is about 0.005% [25]. Sulphur, selenium, lead and tin are known as the additive elements which are useful for improvement of machinability. These elements are added about 0.01-0.15% for sulphur, 0.030.2% for selenium, 0.03-0.2% for lead and 0.01-0.8%for tin [16,25]. The addition of copper to Hadfield steel results stabilizing austenitic structure [31]. The physical properties of Hadfield steel are important in case of machining which are given in Table 2. It should be noted that the work-hardening property varies in a wide range. This is the main influential parameter on the machinability of Hadfield steel. It should be mentioned that the yield strength of the material is very high which causes poor machinability.

Table 1. Chemical composition of some Hadfield steels [31] Chemical ASTM A 128 Grade Composition (%) A B1 C C 1.05 – 1.35 0.90- 1.05 1.05 – 1.35 Mn 11.0 (min) 11.5 – 14.0 11.5 – 14.0 Cr --1.5 – 2.5 Mo ---Ni ---Si 1.00 1.00 1.00 P 0.07 0.07 0.07 The second important element is Mn which contributes the vital austenite-stabilizing effects of delaying transformation. However Mn content has little influence on yield strength but it makes the material non-magnetic. If C and Mn are lowered together such as 0.53% C with 8.3% Mn or 0.62% C with 8.1% Mn, the work-hardening rate increased due to formation of strain-induced martensite. It should be noted that the austenitic structure is not only depended on Mn amount, there is a balance between the amounts of C and Mn. As the C amount increases, austenitic property can be obtained by using lesser amount of Mn [26,30,31]. Mn is cheaper austenitic stabilizer, but the excess of 30% Mn increases the cost of manufacturing and complicates the manufacturing steps. As noted from Table 1, silicon (Si) and phosphorus (P) are presented in all Hadfield type steels. Si content is around 1% and this level can be up to 2% if the yield strength is expected higher. Increase on yield strength is generally obtained by using other elements. More Si content (higher than 2.3%) makes the material worthless and less Si amount (below than 0.10%) decreases fluidity during casting of this material [31]. Si also plays as deoxidizer element in Hadfield steel, but this result can be obtained by aluminium addition [30]. The effect of P contributes hot shortness and low elongation at very high temperatures. It also causes hot tears in casting. Therefore the level of P should be kept maximum 0.07% in this material [29,31]. The most commonly used other alloying elements are chromium (Cr), molybdenum (Mo) and nickel (Ni) as can be 3

Conference Paper

Therefore, it is important to find optimum chemical composition for various industrial applications. In the present study, the effect of elements in Hadfield steel is mainly considered from machinability point of the material. The consideration from materials science would be obviously different.

workpiece and cutting tool are also important factors in the machining of Hadfield steel. Otherwise, unstable machining conditions with combination of high strength and low thermal conductivity properties of Hadfield steel would cause machining troubles like charter vibration, higher workhardened machined surface, high tool wear and rough surface finish [33]. Work-hardening property of Hadfield steel results particular problem when machining such material; severely work-hardened surface left by previous machining operation with a badly worn cutting tool. The use of sharp cutting tool and reasonably high feed rates are generally recommended for prevention of damage to cutting tool caused by workhardening. Therefore the sequences of rough and finish machining operations must be carefully organized; hence it is aimed to obtain less work-hardened surface by too many repeated rough machining [1,2,4]. Moreover, cutting tool strongly bonds to the workpiece material in the machining of Hadfield steel and chips often remain stuck to the cutting tool after each machining operation. It is a possibility of a fragment of the cutting tool when the chip is broken away. This case is especially evident when machining of Hadfield steel with cemented carbides cutting tool material, producing poor, erratic cutting tool performance during machining operation [1,2,4,34,35]. Built-up edge formation in the machining of Hadfield steel is generally observed. This case always occurs when low cutting speeds are used for any engineering materials. Therefore, it is recommended to use high cutting speed when Hadfield steel is machined. However, flank wear of the cutting tool increases when high cutting speeds are used [1,2,4,3436,]. The applicable cutting speeds for two different main cutting materials in various machining operations were given in Table 3. It should be noted that carbide cutting tools allow higher cutting speeds comparing to high speed steel (HSS) tools [37].

Table 2. Mechanical properties of Hadfield steel* Mechanical properties Yield strength 350 Mpa Tensile strength 600-1000 Mpa Hardness 180 HV (after quenching from 1000-1050 °C) Thermal expansion 8-17 x 10-6 -°C coefficient Electrical resistivity 710 µ Thermal conductivity 0.0314 calIT/cm.s.°C Work hardenability 180-580 HV *The given physical properties of Hadfield type steel is based on the chemical composition of the material as follow: (%) C:1-1.25, Mn:12-14, Si:0.6 max., P:0.05% max., S:0.04% max., Fe: balance MACHINING OF HADFIELD STEEL The machining of Hadfield steel has various problems due to the material’s work-hardening and low thermal conductivity properties as well as high hardness. Those properties have an important effect on machinability of the material, therefore the selection of optimum machining parameters is vital to obtain higher material removal rate, longer tool life and better surface finish. The examination of machining for Hadfield steel should start with machine tool system. It should have rigid structure absorbing all stresses to minimize structural related problems. Secure fixture and jig should also be used for workpiece and cutting tool. As a result, the machine tool system should be available for machining of Hadfield steel. The selection of cutting tool material is another important parameter in any machining operations. In case of machining Hadfield steel, the selection of cutting tool material should be completed by following requirements fully accomplished [32];

Table 3. Selection of typical cutting speeds according to cutting material and machining operation [37] Machining process Cutting tool material HSS Carbide Turning (rough) 15 30 Turning (finish) 30 60 Milling 10 20 Drilling 5 10

a. Higher hardness at low and high temperatures b. Higher transverse repture strength c. Higher toughness d. Higher compression strength e. Higher thermal shock resistance f. Higher chemical reaction resistance

The usage of new generation cutting tool materials such as cubic boron nitrate (CBN) and ceramic can be considered. CBN cutting tool materials allow to use higher cutting speed compared to carbide cutting tools. One of Hadfield steel machining study provide useful information that CBN cutting tools applicable and tolerate higher cutting speed like up to 150-200 m/min. It was also mentioned that better surface

Moreover, rigid machine tool structure, stable fixture of 4

Conference Paper

finish quality would be achieved by CBN tools in comparison to carbide tools. Moreover, there would be no built-up edge formation with CBN tools. This is the result provide to use higher cutting speed [38]. Ceramic cutting tools can be recommended for finish machining operation in the machining of Hadfield steel. Although the work-hardening thickness would cause some major problems for ceramics but they can be considered for low depth of cut operations [1,33] . The geometry of cutting tool is another important factor in the machining of Hadfield steel. The sharp cutting tool is recommended because worn tool will produce higher workhardening thickness on the machine surface. It is also vital to select low cutting tool radius, hence the contact length between workpiece and cutting tool will be less. The angles on the cutting tool should be carefully selected for obtaining optimum machining condition for Hadfield steel machining. The rake angles were recommended around 5-10° range to control the chip flow and may require increased side clearance angles to prevent rubbing and localized work-hardening [39,40]. The selection of cutting fluid for machining Hadfield steel is generally depended on to improves machinability of the material. It is known that the cold working of Hadfield steel will reduce the ductility of the material which results in machining with a cleaner chip and less tendency for built-up edge. This result produces a better machined surface finish but with some loss of cutting tool life due to the higher hardness level. Therefore, the application of cutting fluid would be beneficial in the machining of Hadfield steel. Moreover, the low thermal conductivity of Hadfield steel requires cutting fluid usage to increase cooling during machining operations. Thus, the selection of cutting fluid should be based on cooling effect and lubrication to decrease work-hardening property [34,35]. The application of cutting fluid should be also carefully carried out to be more beneficial. It was reported that flooding type cutting fluid application was not useful because of low penetration into cutting zone of cutting fluid; however spray type cutting fluid application would provide better machining outputs such as longer tool life up to 40% due to higher penetration to interface between tool-workpiece-chip [37]. Some machining processes such as drilling and grinding have been investigated and reliable information can be obtained. New approaches have been recommended for machining Hadfield steel such as new form of drills [41]. Grinding may be the useful machining operation for Hadfield steel materials, because its low machinability property can be overcame by grinding like producing components near-toshape by casting and using grinding for dimensional accuracy and surface finish quality. As clearly noticed from literature survey, the workhardening property of Hadfield steel is well recognized to be responsible for poor machinability of the material. Therefore it is obviously clear that the machinability can be improved by

reducing work-hardening occurrence. As a result, special machining methods have been developed for machining of hard or difficult-to-cut engineering materials and Hadfield steel is one of them. Hot machining is one of the special machining methods for machining difficult-to-cut materials such as Hadfield steel. The workpiece is preheated or heated by using various heating methods like electric current, plasma, laser etc., during machining operation in the hot machining. This method is not new, but the importance of the hot machining was recognized after 1950’s when new engineering materials have been introduced. Applied heat reduces the shear strength of workpiece material in the vicinity of the shear zone and decreases the cutting forces. The reduction of strength and cutting forces provide a higher machinability property for especially difficult-to-machine materials [42]. The application of hot machining for Hadfield steel is based on the mechanical properties of the material, the hardness sharply decreased with temperature increased after 500 °C (Fig 1). As a result Hadfield steel could be easily machined due to decreasing hardness [38].

Fig 1. The change of hardness vs. temperature [38]. The hot machining of Hadfield steel has been studied by various researchers. These studies also compared hot machining of Hadfield steel to conventional machining operations. The investigations of hot machining of Hadfield steel reported that longer tool life and better surface finish obtained comparing to conventional machining processes. These results were concluded that the heated thickness would reduce work-hardening property of the material and machining become easier. It was also observed that the tool life would be as high as 2-5 times in hot machining comparing to conventional machining [43-53]. 5

Conference Paper

The selected cutting tool materials were generally carbides, it was also mentioned that high electrical and heat conductive cutting tools positively affected tool life. Moreover coated carbide would produce better machining performance in the hot machining of Hadfield steel [46]. Another special machining method is called cryogenic machining in that the cutting zone or cutting tool is cooled by using various cryogens such as liquid carbon dioxide or nitrogen [54]. In the machining of Hadfield steel, the coolant effect of cryogen decreased the high temperature on cutting tool and hence lowered the tool wear. It was also noticed that a better surface finish would be obtained by cryogenic machining of Hadfield steel due to producing clean chip and less built-up edge formation [55,56].

expensive. c- Cutting fluid must be used to improve machining of Hadfield steel. The coolant should be sprayed in to cutting zone instead of flooding type application that would provide a higher tool life. d- The applicable cutting speed is depended on cutting tool material type. The highest cutting speed (up to 200m/min) can be used when CBN tools are used, then carbides and HSS tools. The formation of built up edge will occur when low cutting speeds are used that increases work-hardened thickness of machined surface; therefore it is important to select optimum cutting speed. e- The feed rate is recommended to be selected at moderate value. Low feed rates would cause higher work-hardening due to longer contact between cutting tool and workpiece. f- The depth of cut must be higher than the work-hardened thickness; otherwise higher tool wear will occur. g- Hot machining seems an important solution for Hadfield steel machining. This method, it is extensively studied and reported, provides higher tool life, better surface finish, higher material removal rates. h- Cryogenic machining is seldomly applied in the machining of Hadfield steel. It is reported that it is a promising machining method comparing to conventional grinding. REFERENCES [1] M.C.Shaw, 2005, Metal Cutting Principles, (2. Edition), Oxford University Press, Inc., [2] E.M. Trent, P.K. Wright, 2000, Metal Cutting, Butterworth-Heinemann, Boston, USA [3] Y. Altıntas, 2000, Manufacturing Automation: Metal cutting Mechanics, Machine Tool Vibration, and CNC Design Cambridge University Press, 2000 [4] T. Child, K. Maekawa, T. Obikawa, Y. Yamane, 2000, Metal Machining: Theory and Applications, Arnold, London, UK [5] R. Hadfield, 1884, “Manufacture of steel”, US Patent No:303150, 2 pages [6] R. Hadfield, 1884, “Steel”, US Patent No:303151, 2 pages [7] R. Hadfield, 1886, “Self-hardening manganese steel”, US Patent No:333748, 2 pages [8] R. Hadfield, 1925, Metallurgy and its influence on modern progress, Chapman & Hall, London, UK [9] H. Takahashi, Y. Shindo, H. Kinoshita, T. Shibayama, S. Ishiyama, K. Fukaya, M. Eto, M. Kusuhashi, T. Hatakeyama, I. Sato, 1996, “Mechanical properties and damage behavior of non-magnetic high manganese austenitic steels”, J. Nuclear Materials, 258-263 (2), 1644-1650 [10] T. Sasaki, K. Watanabe, K. Nohara, Y. Ono, N. Kondo , S. Sat, 1982, “Physical and mechanical properties of high manganese steel and its application to various products for commercial use”, Trans. of the Iron and Steel Inst. of Japan, 22 (129), 1010-1020 [11] E. Bayraktar, F.A. Khalid, C. Levaillant, 2004,

Fig 2. Hot machining application

CONCLUSION The present study aimed to provide scientific information for industrial application of Hadfield steel machining by reviewing up-to date studies. As a result, the following conclusions can be drawn from these very limited studies; a- Work-hardening is the vital mechanical property of Hadfield steel when machining is considered. This special property makes the material as “difficult-to-machine”. Its wide possible industrial application is thus restricted by its low machinability. b- When machining is considered, the selection of cutting tool material should be completed carefully. The carbide cutting tools provide better tool life and surface finish comparing to HSS tools. Moreover the coated types would be more useful. However CBN cutting tools produces longer tool life and better surface finish compared to carbide tools, but they are 6

Conference Paper “Deformation and fracture behaviour of high manganese austenitic steel”, J. of Mater. Proc. Tech., 147 (2), 145-154 [12] E. Curiel-Reyna, A. Herrera, V. Castano, M.E. Rodriguez, 2005, “Influence of cooling rate on the structure of heat affected zone after welding a high manganeses steel”, Materials and Manufacturing Processes, 20 (6), 813-822 [13] E. Curiel-Reyna, A. Herrera, V. Castano, M.E. Rodriguez, 2006, “Influences of the precooling treatment in the heat affected zone on the welding in a used Hadfield-type steel”, Materials and Manufacturing Processes, 21 (5), 573-578 [14] C. H. Lorig, 1940, “Alloy steel”, US Patent No: 2206846, 3 pages [15] C. H. Lorig, 1940, “Alloy steel”, US Patent No: 2206847, 3 pages [16] O.E. Harder, 1940, “Austenitic steel”, US Patent No: 2215734, 3 pages [17] F.T. Ward, 1940, “Method of preparing high manganese steel members and the product thereof”, US Patent No: 21855483, 5 pages [18] P.E. Brunberg, 1954, “Process of thermal regulation of work and tools”, US Patent No: 2670528, 3 pages [19] C. H. Armitage, 1960, “Austenitic steel alloy”, US Patent No: 2965478, 6 pages [20] H.S. Avery, H.J. Chapin, 1961, “Easily machinable, nonmagnetic manganese steel”, US Patent No: 3010823, 4 pages [21] A. Theckston, 1976, “Manganese steel”, US Patent No: 4000018, 7 pages [23] R.G. Oskarsson, C.S.G. Ekemar, 1979, “Wear resistant alloy”, US Patent No: 4145213, 11 pages [24] K. Aihara, M.Takahashi, 1980, “Nonmagnetic alloy steel having improved machinability”, US Patent No: 4240827, 5 pages [25] Y. Kasamatsu, S Ishioka, M. Yamaga, H. Hirano, H. Ihara, 1981, “High manganeze non-magnetic steel with excellent weldability and machinability”, US Patent No: 4302248, 10 pages [26] C. Oucki, Y. Kohsaka, 1981, “Method of manufacturing non-magnetic Fe-Mn steel having low thermal expansion coefficients and high yield points”, US Patent No: 4256516, 8 pages [27] C. Ducki, T. Sampei, 1982, “High manganese nonmagnetic steel having excellent machinability”, US Patent No: 4329172, 9 pages [28] D.K. Subramanyan, H.J. Chapin, B.A. Heyer, 1984, “Austenitic-manganese steel”, US Patent No: 4425169, 5 pages [29] H.R. Larson, D.K. Subramanyam, 1986, “Manganese steel”, US Patent No: 4612067, 3 pages [30] S. Kunikoa, H. Toriyama, 1997, “Abrasive resistant high manganese cast steel”, US Patent No: 5601782, 7 pages [31] D.K. Subramanyam, A.E. Swansiger, 1999, “Austenitic manganese steels”, ASM Handbook, Volume 1: Properties and selection: Irons, steels, and high-performance alloys, Ohio, 1999: 822-840

[32] W. Konig, R. Komanduri, 1984, “Machining of hard materials”, Annals of the CIRP, 33 (2), 417-427 [33] T. Kaso, R.P. Ney, 1999, “Machining of stainless steels”, ASM Handbook, Volume 16: Machining, Ohio, 681-707 [34] G.L. Kufarev, V.I. Livshits, 1960, “The machinability of high manganese steels”, Russian Engg. Journal, 46 (6), 75-77 [35] N.S. Molodstov, 1967, “Machining high manganese steels”, Machines & Tooling, 39 (7), 55-56 [36] M. Kıyak, A. Uysal, O. Çakır, E. Altan, 2012, ”Tool life in orthogonal turning of high manganese steel with edged radius carbide cutting tools”, Proceeding of 3rd National machining Symposium, 4-5 October 2012, Ankara, Turkey, 496-502 [in Turkish] [37] J. Valentine, J. Goldenberg, 2003, Introduction to Computer Numerical Control (CNC), Prentice Hall, 521-524 [38] J. Kopac, 2001, “Hardening phenomena of Mn-austenite steels in the cutting process”, J. of Mater. Proc. Tech., 109 (12), 96-104 [39] P. Zimin, V.I. Malevannyi, 1965, “Turning austenitic steel with diamond ground tools”, Machines & Tooling, 36 (8), 3032 [40] M. Xiao, K. Sato, S. Karube, T. Soutome, 2003, “The effect of tool nose radius in ultrasonic vibration cutting of hard metal”, Int. J. Machine Tools & Manufacture, 43, (13), 13751382 [41] Y.P. Han, J.F. Meng, J.Q. Zhou, 2004, “A new type of non-chisel-edge shallow-drill for machining high manganese steel”, Materials Science Forum, 471-472, 422-425 [42] O. Çakır, E. Altan, 2005, “A brief review of hot machining”, Proc. of the 9th Int. Research/Expert Conference (TMT 2005), Antalya, Turkey, 41-44 [43] E. Armstrong, A.S. Cosler, E.F. Katz, 1951, “Machining of heated metals”, Trans. Of the ASME, 73(1), 1951:35-43 [44] R. Dioguardi, 1965, “Method of Cutting Metals”, US Patent No: 3220149, 1965: 7 pages [45] D.K. pal, S.K. Basu, 1971, “Hot machining of austenitic manganese steel by shaping”, Int. J. of Machine Tool Design and Research, 11(1), 45-61 [46] K. Uehara, M. Sakurai,H. Takeshita, 1983, “Cutting performance of coated carbides in electric hot machining of low machinability metals”, Annals of the CIRP, 32 (1), 97-100 [47] K. Maekawa, T. Kitagawa, 1986, “Simulation analysis of cutting mechanism in plasma hot machining”, Bull. Japan Society of Precision Engineers, 20 (4), 285-286 [48] K. Maekawa, A. Kubo, T. Kitagawa, 1988, “Simulation analysis of cutting mechanism in plasma hot machining of high manganese steels”, Bull. Japan Society of Precision Engineers, 22 (3), 183-189 [49] A.K. Roy, S.K. Ray, T.D. Chatterjee, S. Jha, V. Ramaswamy, 1992, “Drilling of thick Hadfield manganese steel plate”, Materials Forum (Australia), 16 (1), 57-61 [50] O. Çakır, E. Altan, 1994, “The effects of the positive and negative rake angles on the tool life and surface roughness in the hot and conventional machining of high manganese steel”, 7

Conference Paper

Materials Issues in Mach.-II and The Physics of Mac. Proc.-II, Metals & Materials Society, Ohio, USA, 105-116 [51] L. Ozler, A. Inan, C. Ozel, 2001, “Theoretical and experimental determination of tool life in hot machining of austenitic manganese steel”, Int. J. of Machine Tools & Manufacture, 41 (2), 163-172 [52] N. Tosun, L. Ozler, 2002, “A study of tool life in hot machining using artificial neural network and regression analysis method”, J. of Mater. Proc. Tech., 124 (1-2 ), 99-104 [53] N. Tosun, L. Ozler, 2004, “Optimization for hot turning operations with multiple performance characteristics”, Int. J. Adv. Manf. Tech., 23 (11-12), 777-782 [54] O. Çakır, M. Kiyak, E. Altan, 2002, “Cryogenic machining: A review”, Proc. of 4th GAP Engineering Congress, Sanliurfa, Turkey, Vol:1, 277-284 [55] P.E. Brunberg, 1994, “Process of thermal regulation of work and tools”, US Patent No:2670528, 3 pages [56] J.K.N. Murthy, A.B. Chattopadhyaya, A.K. Chakrabarti, 2000, “Studies on the grindability of some alloy steels”, J. of Mater. Proc. Tech., 104 (1-2), 59-66

8