فهرست مقالات Machinability

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  1 - Machinability evaluation of Titanium alloy in Laser Assisted Turning
  Kamran Puladsaz Razavi Shojae Rezavi Mehdi Tajaddara
  The use of titanium and its alloys has increased in various industries recently, because of their superior properties of these alloys. Titanium alloys are generally classified as difficult to machine materials because of their thermo-mechanical properties such as high s چکیده کامل

  The use of titanium and its alloys has increased in various industries recently, because of their superior properties of these alloys. Titanium alloys are generally classified as difficult to machine materials because of their thermo-mechanical properties such as high strength-to-weight ratio and low thermal conductivity. Laser Assisted Machining (LAM) improves the machinability of high strength materials in various aspects. LAM is a high temperature cutting process using a laser beam as the heat source. The laser is used as an intense heat source to increase workpiece temperature locally and decrease the strength of the machined material in front of the cutting tool. Decreasing of workpiece material strengh in material removal region resulted to improvement of material removal conditions. In this study the effectiveness of the LAM on machinability of Ti6Al4V is invetigated by compared to conventional machining in varying process parameters such as cutting speed, feed rate, laser power and material removal temperature. The machinability of the titanium alloy under varying conditions is evaluated by examining specific cutting energy, surface roughness and chip morphology. This investigation has shown that LAM reduces specific cutting energy about 30% and improvement of surface roughness as compared to conventional machining. پرونده مقاله
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  2 - Machinability Investigation of Inconel 657 in High-speed Turning
  Amir Hossein Khoei Hasan Fathi Masoud Farahnakian Mohammad Reza Razfar
  A high strength nickel chromium alloy (50Cr-50Ni-Nb alloy), commonly referred to as IN-657, is specifically used for components in furnaces which are fired by low grade fuel oils containing high levels of vanadium, sodium and sulphur. The purpose of this study is to exp چکیده کامل

  A high strength nickel chromium alloy (50Cr-50Ni-Nb alloy), commonly referred to as IN-657, is specifically used for components in furnaces which are fired by low grade fuel oils containing high levels of vanadium, sodium and sulphur. The purpose of this study is to experimentally investigatethe effect of machining parameters on machinability in turning of Inconel 657. The considered parameters were cutting speed, feed and tool material. Cutting force components, tool flank wear and surface roughness were measuredbased on design of experiments, and then analysis of variance was performed. Experimental results show that tool wear of CBN tools is 50 %lower than that of carbide tools. The Tool material with percentage contribution of 48% and 56% is the main parameter that influencesthe cutting forces and the flank wear, respectively. Also, the cutting speed with percentage contribution of 48% is the main parameter that effects the surface roughness. The lowest surface roughness is attained by the cutting speed of 250 m/min and the feed of 0.05 mm/rev by the CBN tool. پرونده مقاله
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  3 - Machinability Improvement of 17-4PH Stainless Steel by Cryogenic Cooling
  Salman Khani Mohammad Razfar Masoud Farahnakyan
  17-4PH stainless steel is a martensitic precipitation hardening stainless steel that provides an outstanding combination of high strength, good corrosion resistance, good mechanical properties, good toughness in both base metal and welds, and short time, low-temperature چکیده کامل

  17-4PH stainless steel is a martensitic precipitation hardening stainless steel that provides an outstanding combination of high strength, good corrosion resistance, good mechanical properties, good toughness in both base metal and welds, and short time, low-temperature heat treatments that minimize warpage and scaling. This valuable alloy is widely used in the aerospace, nuclear, chemical, petrochemical, food processing, power generation, and naval industries; however, 17-4PH stainless steel is categorized as hard to machine materials due to low thermal conductivity and high toughness. Tool wear in traditional machining of 17-4PH stainless steel is high; hence, low tool life causes high tooling cost. In this paper, indirect cryogenic machining was used, in order to improve machinability of 17-4PH stainless steel in turning operation with TiN coated carbide insert tool. Pressurized-liquid-nitrogen (LN) was used as a cryogenic coolant. Nitrogen gas applied on the liquid nitrogen to pressurize it. A specific tool holder was designed and manufactured for cryogenic turning. Cryogenic machining decreases temperature-dependent tool wear and increases tool life by keeping tool temperature low. Cutting force, tool flank wear and maximum tool temperature have been studied as machinability parameters. Cutting force was measured by the Kistler 9121 piezoelectric dynamometer. The Dino-Lite digital microscope with 20-200X magnification was used to measure tool flank wear. The experimental results showed that cryogenically enhanced machining decreases cutting force and tool flank wear by 22 and 23 percent, respectively, compared with dry turning. Predicting of tool life using linear extrapolation showed that tool life in cryogenic turning improved by 39% over dry turning. In addition, cutting force in cryogenic machining became more stable than the force in dry condition. Thermal analysis of the carbide tool performed in the ANSYS Software using experimental data. Thermal analysis showed that the maximum temperature of cutting tool in cryogenic machining is 75 percent lower than dry condition. پرونده مقاله