Improvement of Chip Breaking in Machining Low Carbon Steel by Cryogenically Precooling the Workpiece

1998 ◽  
Vol 120 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Y. Ding ◽  
S. Y. Hong

Ductile materials such as AISI1008 low carbon steel characteristically exhibit poor chip breaking in conventional machining practices. This paper presents an environmentally clean cryogenic machining process which improves the breakability of AISI1008 chips by lowering the chip temperature to its embrittlement temperature. In this study, the brittle-ductile transition temperature of AISI1008 was experimentally determined to be between −60°C and −120°C. The discussion is focused on whether the chip can reach the embrittlement temperature before it hits an obstacle. A finite element simulation predicted the chip temperatures under various cutting conditions. Liquid nitrogen (LN2) was used to prechill the workpiece cryogenically. The results from the cutting tests indicate a significant improvement in chip breakability for different feeds and speeds by using this cooling technique. However, the effectiveness of cryogenetically prechilling the workpiece was found to be heavily dependent on cutting speed.

2009 ◽  
Vol 633-634 ◽  
pp. 471-480
Author(s):  
Masaki Tanaka ◽  
Kenji Higashida ◽  
Tomotsugu Shimokawa

Brittle-ductile transition (BDT) behaviour was investigated in low carbon steel deformed by an accumulative roll-bonding (ARB) process. The temperature dependence of its fracture toughness was measured by conducting four-point bending tests at various temperatures and strain rates. The fracture toughness increased while the BDT temperature decreased in the specimens deformed by the ARB process. Arrhenius plots between the BDT temperatures and the strain rates indicated that the activation energy for the controlling process of the BDT was not changed by the deformation with the ARB process. It was deduced that the decrease in the BDT temperature by grain refining was not due to the increase in the dislocation mobility controlled by short-range barriers. Quasi-three-dimensional simulations of dislocation dynamics, taking into account of crack tip shielding due to dislocations, were performed to investigate the effect of a dislocation source spacing along a crack front on the BDT. The simulation indicated that the BDT temperature is decreased with decreasing in the dislocation source spacing. Molecular dynamics simulations revealed that moving dislocations were impinged against grain boundaries and were reemitted from there with increasing strain. It indicates that grain boundaries can be new sources in ultra-fine grained materials, which increases toughness at low temperatures.


2013 ◽  
Vol 315 ◽  
pp. 57-62 ◽  
Author(s):  
Sia Chee Kiong ◽  
Loo Yee Lee ◽  
Siaw Hua Chong ◽  
Mohd Azwir Azlan ◽  
Nik Hisyamudin Muhd Nor

This study is an approach to investigate the environmental impact of screw manufacturing and to choose suitable material for selected screw-making processes for the best performance with minimum environmental impact. The parameters involved were types of material and screw-making process using the environmental data available in Asia region. The two different manufacturing approaches being evaluated were machining and forging. The types of material considered were low carbon steel, stainless steel, titanium alloy and aluminium alloy. As for machining process, the materials being considered in screw manufacturing were low carbon steel, stainless steel, titanium alloy, aluminium alloy, magnesium alloy and cast iron. The information of environmental impact are generated by SolidWorks. Sustainability tool was used in the formation of pair-wise comparison matrices for Analytic Hierarchy Process (AHP). Then, the ranking of global priorities had enabled the determination of appropriate material to be used for those selected screw manufacturing process. As a result, aluminium alloy was found to give minimum environmental impact for forging process whereas cast iron was found to excel in machining process. At the same time, titanium alloy was not suggested to be used in either process.


2013 ◽  
Vol 465-466 ◽  
pp. 1065-1069
Author(s):  
Mohd Azwir Azlan ◽  
Andy Anak Buja ◽  
Sia Chee Kiong ◽  
Nik Hisyamudin Muhd Nor ◽  
Jalil Azlis-Sani

This study is an approach to investigate the viable impacts of screw manufacturing. At the same time, choose the suitable material and selected manufacturing process of screw by considering environmental aspects without sacrificing the economic aspect. It is important to the organisation to improve the environmental aspect. Therefore in this study, the decision making was focused on economic aspects to produce the synergy results between economic and environmental impact. The parameters involved were types of material and manufacturing process of screw which using the available data of environmental and production volume. The two different manufacturing approaches being evaluated were machining and forging process. The types of material concerned for forging process encompassed low carbon steel, alloy steel stainless steel, and aluminium alloy. On the other hand, for machining process, the material being considered in screw manufacturing were cast iron, low carbon steel, alloy steel, stainless steel and aluminium alloy. The information of environmental impacts that generated from SolidWorks Sustainability tool and screw production cost were calculate using Manufacturing cost model, both information was used in Analytic Hierarchy Process (AHP) analysis to obtain local priority of economic and environmental impacts. Then, the ranking of both global and local priorities from economic impact and environmental impacts had enabled the determination of appropriate material used for those selected screw manufacturing process. As result, low carbon steel was chosen for forging process whereas cast iron was excelled in machining process, at the same time, stainless steel was not suggested to be used in both two processes.


2019 ◽  
Vol 297 ◽  
pp. 01007
Author(s):  
Aleksandr Loktionov ◽  
Nadezhda Gaar ◽  
and Аndrey Rakhimyanov

The results of the investigations on determining the processing modes during high-precision plasma cutting of low carbon steel based on the values of Peclet number and dimensionless power which provide the minimal value of deviation of the cut sides from perpendicularity are presented in the paper. The conditions of obtaining the cut of high quality from the viewpoint of minimizing the cut side deviation from perpendicularity are determined by cutting low carbon steel. The dependences of the cutting speed and the cut width on the processed material thickness, intended to determine the processing modes and adjustment of the linear dimensions are established. The investigations were made on the device of the thermal cutting “Termit PPl” based on the installation of the high-precision plasma cutting HiFocus 130i of Kjellberg firm by using the HiFocusplus technology. Low carbon construction steel St3 was chosen as an investigated material. The thickness of the sheet material constituted 4 mm, 6 mm, 10 mm, 16 mm and 20 mm.


Author(s):  
Abdullah Tariq AL-Malki ◽  
Basim Khidhir

This research focuses on enhancing the surface roughness of low carbon steel by heat treatment of low carbon steel in turning operation. Heat treatment is mainly used to improve the mechanical properties of materials. Two sets of specimens used during the experiment where each has 5 pieces of mild steel that heat-treated of two-level of temperatures of 650 oC and 900oC. After the heating process of all specimens, it will be exposed to different coolant media which are quenching, normalizing and annealing. A carbide single-point tool, one level of cutting parameters selected as one level of cutting speed and depth of cut and two levels of feed rate used during this research. The results show that specimen quenched by oil bath measures the highest value of the surface roughness of 8.26 µm at 900oC and machined with a feed rate of 0.113 mm. While quenched water specimens show less surface roughness of 4.91µm at 650oC in the same feed rate.


Machines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 190
Author(s):  
Liang-Wei Tseng ◽  
Teng-Shan Hu ◽  
Yuh-Chung Hu

Real-time monitoring of the cutting force in the machining process is critical for improving machining accuracy, optimizing the machining process, and optimizing tool lifetime; however, the dynamometers are too expensive to be widely used by machine tool users. Therefore, this paper presents a simple and cheap apparatus—a smart tool holder—to measure the cutting force of turning tools in the finishing turning. The apparatus does not change the structure of the turning tool. It consists of a tool holder and a piezoresistive force sensor foil, and transmits the signal through Bluetooth wireless communication. Instead of dealing with the circuit hardware, this paper uses the Artificial Neural Network (ANN) model to successfully calibrate the warm-up shift problem of the piezoresistive force sensor. Such a software method is simple, and considerably cheaper than the hardware method. For the force measurement capability of the smart tool holder, the cross-interference between orthogonal forces are very small and thus can be ignored. The force reading of the smart tool holder possesses high repeatability for the same turning parameters and high accuracy within the experiment groups. The authors apply the smart tool holder to cut the low carbon steel S15C, and to determine its specific cutting force in fine turning. The resulting fine turning force model agrees very well with the measurement. Its mean absolute deviation is 3.87% and its standard deviation is 1.55%, which reveals that the accuracy and precision of the smart tool holder and the fine turning force model are both good.


2013 ◽  
Vol 554-557 ◽  
pp. 287-299
Author(s):  
Jing Cai Wang ◽  
Laurent Langlois ◽  
Muhammad Rafiq ◽  
Régis Bigot ◽  
Hao Lu

The presented work is dedicated to studying the forgeability of bimaterial cladded workpiece. Hot upsetting tests of cylindrical low carbon steel (C15) billets weld cladded (MIG) by stainless steel (SS316L) are experimentally and numerically studied. Upsetting tests with different upsetting ratios are performed in different tribology conditions at 1050°C which is within the better forgeability temperature range of both substrate and cladding materials[ ]. Slab model and finite-element simulation are conducted to parametrically study the potential forgeability of the bimaterial cladded workpiece. The viscoplastic law is adopted to model the friction at the die/billet interface. The friction condition at the die/billet interface has a great impact on the final material distribution, forging effort and cracking occurrence. With Latham and Cockcroft Criterion, the possibility and potential position of cracks could be predicted.


1993 ◽  
Vol 90 (7-8) ◽  
pp. 917-922
Author(s):  
Y. Matsuda ◽  
M. Nishino ◽  
J. Ikeda

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