scholarly journals Effect of MnS on the Cutting Mechanism of Powder Metallurgy Steel in Cutting Speeds Ranging from 1 m/s to 150 m/s

2012 ◽  
Vol 565 ◽  
pp. 370-375 ◽  
Author(s):  
Jun Shinozuka ◽  
Hidenobu Yachi ◽  
Tappei Higashi ◽  
Masato Sando ◽  
Toshio Maetani ◽  
...  

Orthogonal cutting experiment of powder metallurgy steel was performed in cutting speeds ranging from 1 m/s to 150 m/s. High-speed cutting experiment was carried out with a high-speed impact-cutting tester. This study focuses on the change in the effects of free-cutting of manganese sulfide with cutting speed. The principal force and thrust force were measured. The cross sections of the chip and of the machined surface were observed. Color mapping analysis of the tool-chip contact region on the rake face with EPMA was done. Although the serrated type of chip formed in all experiments, the cutting mechanism was analyzed by employing a shear plane model. This paper discusses how the effect that MnS promotes the ductile fracture and the effect that MnS improves the friction property at the tool-chip interface change as the cutting speed increases.

2012 ◽  
Vol 523-524 ◽  
pp. 1041-1046 ◽  
Author(s):  
Tappei Higashi ◽  
Masato Sando ◽  
Jun Shinozuka

High-speed orthogonal cutting experiments with cutting speeds of up to 200 m/s with a high-speed impact cutting tester of air-gun type are attempted. In this tester, a light projectile with a small built-in cutting tool is loaded into a tube, being accelerated by a compressed gas. The projectile captures the chip that is indispensable to analyze the cutting mechanism. The projectile holding the chip is decelerated by another compressed gas just after finishing the cutting, being stopped without damage in the tube. Successful experiment can be accomplished by setting adequate values of the operation parameters for the experiment, which are the pressure of each gas and the opening and shutting time of the solenoid-controlled valve for each compressed gas. In order to determine the adequate values of these parameters, a ballistic simulator that simulates the velocity and position of the projectile traveling in the tube is developed. By setting the values of these parameters obtained by the simulator, the cutting speed of 200 m/s is achieved when the ambient pressure is set to be a vacuum and helium is used for each compressed gas. This paper describes the ballistic simulator developed and shows the experimental results of the high-speed cutting of aluminum alloy A2017.


2010 ◽  
Vol 431-432 ◽  
pp. 114-117
Author(s):  
Hai Dong Yang ◽  
Zhen Hua Qing ◽  
Feng Xie ◽  
Chong Gao Zhang

This paper deals with the High-speed Hard and Dry Cutting mechanism of hardened alloy-steel with PCBN tool: the cutting speed and workpieces temperature and tool wear are being discussed in different cutting speeds when cutting alloy-steel 42CrMo. After the workpiece temperature measured by ThermaVision, it is proved that the workpiece temperature was not high and changed little. Through the SEM and EDS analyses for chip and tool wear, it is proved that PCBN tool is suitable for High-speed Hard and Dry Cutting. It is suitable for PCBN tool to cut hardened alloy-steel 42CrMo instead of grinding.


2016 ◽  
Vol 874 ◽  
pp. 450-456
Author(s):  
Jun Shinozuka ◽  
Daiki Kidoura

This paper investigated the variation in a heat partition ratio of the cutting tool with the cutting speed ranging from 38 m/min to 6500 m/min. The orthogonal high-speed cutting experiment was performed utilizing an impact cutting tester developed. The cutting length in this study was 60 mm. The temperatures at the tool-chip interface were measured directly with three pairs of Cu/Ni micro thermocouples fabricated on the rake face. The temperature rises rapidly from the beginning of cutting, and then levels off when a cutting distance exceeds about 10 to 20 times the depth of cut. The distance depends on the cutting speed. Using the temperatures measured, a variation in the heat partition ratio with cutting time was estimated with the aid of a FEA. The heat partition ratio at the end of cutting estimated decreases approximately from 7 % to 1 % as the cutting speed increases from 38 m/min to 6500 m/min. The heat partition ratio estimated is quite higher than that calculated by employing an analysis assuming the steady state, particularly under the high speed cutting conditions.


Alloy Digest ◽  
1978 ◽  
Vol 27 (12) ◽  

Abstract STORA ASP 60 is a molybdenum-tungsten high-speed steel with high percentages of carbon, cobalt and vanadium. It is a powder metallurgy steel, has high hardenability and can be hardened by cooling in air or oil from the austenitizing temperature. It has an excellent combination of wear resistance, toughness, hot hardness and resistance to tempering. It is recommended for cutting tools for hard-to-machine material and high cutting speeds. This datasheet provides information on composition, physical properties, microstructure, hardness, and elasticity. It also includes information on forming, heat treating, and machining. Filing Code: TS-342. Producer or source: Stora Kopparberg, Special Steels Division.


2017 ◽  
Vol 889 ◽  
pp. 84-89
Author(s):  
Pandithevan Ponnusamy ◽  
Mullapudi Joshi

In high speed machining, to dynamically control the mechanical behaviour of the materials, it is essential to control temperature, stress and strain by appropriate speed, feed and depth of cut. In the present work, to predict the mechanical behaviour of Ti6Al4V and 316L steel bio-materials an explicit dynamic analysis with different cutting speeds was carried out. Orthogonal cutting of 316L steel and Ti6Al4V materials with 720 m/min, 900 m/min and 1200 m/min cutting speeds was performed, and the distribution of stress and temperature was investigated using Jonson-Cook material model. Additionally, the work aimed at determining the effect of cutting speed on work piece temperature, when cutting is carried out continuously. From the investigation, it was found that, while machining Ti6Al4V material, for the increase in cutting speed there was increase in tool-chip interface temperature. Specifically, this could found till the cutting speed 900 m/min. But, there was a decrease in tool-chip interface temperature for the increase in speed from 900 m/min to 1200 m/min. Similarly for 316L steel, the tool-chip interface temperature increased when increasing the cutting speed till 900 m/min. But reduction in temperature from 650 °C to 500 °C for steel and 1028 °C to 990 °C for Ti6Al4V were found, when the cutting speed increased from 900 m/min to 1200 m/min. The study can be used to conclude, at what temperature range the adoption of material with controlled shape and geometry is possible for potential applications like, prosthetic design and surgical instruments prior to fabrications.


1999 ◽  
Author(s):  
S. Barnes ◽  
M. J. Nash ◽  
M. H. Lim

Abstract Improvements in the machining performance of ferrous powder metallurgy (PM) materials has recently been reported by one of the main manufacturers of metal powders. This improvement in machinability reportedly being achieved by the addition of a new free-machining additive which is marketed under the trade name of “MnX”. The work reported here, investigated this claim by comparing the performance of three PM materials with the same basic composition but different free-machining additives. The first material contained no free-machining additive, the second, contained the conventional manganese sulphide (MnS) additive and the third contained the new MnX additive. A turning operation was used to compare the performance of the three materials at cutting speeds in the range of 100–250 m/min using titanium nitride (TiN) coated UE6005 carbide inserts. The relative performance of the three materials was compared by measuring cutting forces, tool wear and the surface finish produced on the workpiece. It was found that at all cutting speeds investigated, the material containing MnX gave a superior performance. However, at higher cutting speeds the superiority of the material containing MnX was much more significant. In contrast, at the lowest cutting speed of 100 m/min, it was found that although the material containing MnX continued to exhibit the best performance, the differences between the three materials were substantially reduced and the material containing no free machining additive actually generated slightly less wear than the material containing MnS. The results therefore confirm that the new MnX additive is superior to the conventional MnS additive. However, this work has also demonstrated that relatively high cutting speeds are needed in order to obtain optimum benefits from the new additive.


Author(s):  
Justin L. Milner ◽  
Jeffrey A. Beers ◽  
John T. Roth

Machining is a popular and versatile manufacturing process that is widely used in today’s industry when producing metallic parts; however, limited tool life can make this an expensive and time consuming fabrication technique. Consequently, methods that decrease the rate of tool wear and, thus, increase tool longevity are a vital component when improving the efficiency of machining processes. To this end, cryogenically treating cutting tools (especially high-speed steel tooling) is becoming more commonplace since research has shown that the treated tooling exhibits significantly higher wear resistance. At this point, however, the effect of cryogenic treatments on ceramic tooling has not been established. Considering this, the research herein presents a feasibility study on the effectiveness of using cryogenic treatments to enhance the wear resistance of WG-300 whisker-reinforced ceramic cutting inserts. To begin, the effect of the cryogenic treatment on the insert’s hardness is examined. Subsequently, tool wear tests are conducted at various cutting speeds. Through this study, it is shown that cryogenically treating the ceramic inserts decreases the rate of tool wear at each of the cutting speeds that were tested. However, the degree of wear resistance introduced by cryogenically treating the inserts proved to be highly dependent on the cutting speed, with slower speeds exhibiting greater improvements. Thus, based on this initial study, the cryogenic treatment of ceramic tooling appears to produce beneficial results, potentially increasing the overall efficiency of machining processes.


2011 ◽  
Vol 188 ◽  
pp. 578-583 ◽  
Author(s):  
Toshiyuki Obikawa ◽  
Masahiro Anzai ◽  
Tsuneo Egawa ◽  
Norihiko Narutaki ◽  
Kazuhiro Shintani ◽  
...  

This paper describes strong nonlinearity in log V-log L relationship, which is often found in machining of supperalloys, titanium alloys, hardened steels, cast irons, etc. The nonlinearity plays an important and favorable role in extension of life-span cutting distance at higher cutting speeds; that is, in a certain range of cutting speed, life-span cutting distance increases with cutting speed. Results of tool wear in a sliding test and cutting experiments, which showed the evidences of strong nonlinearity, were investigated and the mechanisms causing the nonlinearity were discussed.


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