Investigation into the Grindability and Surface Integrity of the Nickel Base Superalloy Using Liquid Nitrogen Jet Grinding

2010 ◽  
Vol 426-427 ◽  
pp. 49-54 ◽  
Author(s):  
Chang He Li ◽  
Ya Li Hou ◽  
Yu Cheng Ding
Keyword(s):  
Surface Integrity ◽  
High Speed ◽  
Ground Surface ◽  
Cryogenic Cooling ◽  
Cutting Fluid ◽  
Nickel Base Superalloy ◽  
Grinding Process ◽  
Machining Processes ◽  
Grinding Conditions ◽  
Nickel Base

Grinding processes are mainly technique employed widely as a finishing process in a variety of materials, such as metals, hardness and brittleness and ductile materials machining to achieve good dimensional and form accuracy of the product with acceptable surface integrity. However, grinding is associated with high specific energy requirements which may be an order higher than that required in other conventional machining processes such as turning, planning, milling etc. Therefore, in grinding process, high grinding zone temperature may lead to thermal damage to the work surface, induces micro-cracks and tensile residual stresses at the ground surfaces, which deteriorate surface quality and integrality of the ground surface. Therefore, grinding fluids are applied in different forms to control such high temperature, but they are ineffective, especially under high speed grinding conditions where the energy of the fluid is not sufficient to penetrate the boundary layer of air surrounding the wheel. Moreover, the conventional flood supply system demands more resources for operation, maintenance, and disposal, and results in higher environmental and health problems. Therefore, there are critical needs to reduce the use of cutting fluid in grinding process, and cryogenic cooling grinding is a promising solution. The work presented in this paper aims at evaluating the grind ability and surface integrity of the nickel base super alloy resulting from the application of cryogenic cooling.

Analytical and Experimental Investigation of the Nickel Based Superalloy Using Cryogenic Cooling Grinding

2009 ◽  
Vol 69-70 ◽  
pp. 354-358 ◽  
Author(s):  
Chang He Li ◽  
Yu Cheng Ding ◽  
Bing Heng Lu ◽  
Guang Qi Cai
Keyword(s):  
Surface Quality ◽  
Surface Integrity ◽  
Ground Surface ◽  
Cryogenic Cooling ◽  
Nickel Base Superalloy ◽  
The Novel ◽  
Nickel Based Superalloy ◽  
Micro Cracks ◽  
Force Components ◽  
Nickel Base

Grinding processes are mainly technique employed widely as a finishing and difficult-to machine such as hardness and brittleness materials machining. However in grinding process, high grinding zone temperature may lead to thermal damage to the work surface, induces micro-cracks and tensile residual stresses at the ground surfaces, which deteriorate surface quality and integrality of the ground surface. The work presented in this paper aims at evaluating the grindability and surface integrity of the nickel base superalloy resulting from the application of cryogenic cooling. Grinding experiments were conducted under three different environments: dry, mineral oil and cryogenic cooling jet. The grindability results have shown that while the cryogenic cooling generates the lowest grinding temperature, no significant differences over the specific grinding force components were observed. As for the ground surface integrity, however, substantial improvements were realized. The novel process not only obviously enhances surface quality and integrality of grinding surface, but also enables retention of the wheel sharpness for a longer period and reduces pollution of grinding fluid to nature.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
High Speed ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Edge Contact ◽  
Cylindrical Grinding ◽  
Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

The Influence of Cutting Fluid Concentration on Surface Integrity of VP80 Steel and the Influence of Cutting Fluid Flow Rate on Surface Roughness of VPATLAS Steel After Grinding

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Raphael Lima de Paiva ◽  
Rosemar Batista da Silva ◽  
Mark J. Jackson ◽  
Alexandre Mendes Abrão
Keyword(s):  
Surface Roughness ◽  
Flow Rate ◽  
Surface Integrity ◽  
Ground Surface ◽  
Cutting Fluid ◽  
Depth Of Cut ◽  
Fluid Concentration ◽  
Grinding Conditions ◽  
Temperature Levels ◽  
Grinding Operations

The application of cutting fluid in grinding operations is crucial to control temperature levels and prevent thermal damage to the workpiece. Water-based (emulsions and solutions) coolants are used in grinding operations owing to their excellent cooling capability and relatively lower cost compared to neat oils. However, the cutting fluid efficiency is not only dependent on its type, but also on other parameters including its concentration and flow rate. In this context, this work aims to analyze the influence of the coolant concentration and flow rate on the grinding process. Two different workpiece materials for the production of plastic injection moulds were machined: VP80 and VPATLAS steel grades. Six grinding conditions (combinations of depth of cut values of 5, 15, and 25 μm with coolant concentration of 3% and 8%, respectively) were employed in the former, while two grinding conditions were used for the latter. The output parameter used to assess the influence of coolant concentration and flow rate on the grinding operation focused on the integrity of the workpiece materials (surface roughness and microhardness below the ground surface). The results showed that the surface integrity of VP80 after grinding was more sensitive to depth of cut than to cutting fluid concentration. Furthermore, the highest coolant concentration outperformed the lowest one when grinding under more severe conditions. With regard VPATLAS steel, no influence of the coolant flow rate on surface roughness was observed.

Ultra-High Speed Grinding Using a CBN Wheel for a Mirror-Like Surface Finish

2005 ◽  
Vol 291-292 ◽  
pp. 67-72 ◽  
Author(s):  
M. Ota ◽  
T. Nakayama ◽  
K. Takashima ◽  
H. Watanabe
Keyword(s):  
Surface Finish ◽  
High Speed ◽  
High Efficiency ◽  
Ground Surface ◽  
Machining Process ◽  
Grinding Wheel ◽  
Cbn Wheel ◽  
Ultra High Speed ◽  
High Speed Grinding ◽  
Grinding Conditions

There are strong demands for a machining process capable of reducing the surface roughness of sliding parts, such as auto parts and other components, with high efficiency. In this work, we attempted to grind hardened steel to a mirror-like surface finish with high efficiency using an ultra-high speed grinding process. In the present study, we examined the effects of the work speed and the grinding wheel grain size in an effort to optimize the grinding conditions for accomplishing mirror-like surface grinding with high efficiency. The results showed that increasing the work speed, while keeping grinding efficiency constant, was effective in reducing the work affected layer and that the grinding force of a #200 CBN wheel was lower than that of a #80 CBN wheel. Based on these results, a high-efficiency grinding step with optimized grinding conditions was selected that achieved excellent ground surface quality with a mirror-like finish.

WC-Co Tool Failure Analysis and the Grinding Effect Study

2010 ◽  
Vol 139-141 ◽  
pp. 269-273 ◽  
Author(s):  
Xiu Xu Zhao
Keyword(s):  
Residual Stress ◽  
Effect Study ◽  
Work Piece ◽  
Grinding Process ◽  
X Ray Diffraction ◽  
Machining Processes ◽  
Tool Failure ◽  
Micro Cracks ◽  
Comparison Results ◽  
Grinding Conditions

Grinding is one of the important machining processes for the WC-Co carbide product. Different grinding strategies will have different impact on the work piece material. This study focuses on the WC-Co carbide grinding process, and the effect of grinding condition on the WC-Co carbide microstructure, figures out the relationship between different grinding strategies and material microstructure which relate to the WC-Co carbide tool failure. A specific microstructure analysis with Scanning Electric Microscope (SEM) will be presented based on a series of grinding experiments. The residual stress that generated in the grinding process will also be discussed based on the X-Ray Diffraction (XRD) measurements. It has been found that micro cracks are generated at certain grinding conditions with certain level. The residual stress which generated in the grinding process can be calculated by the d-spacing shift, and the comparison results show micro-cracks level is corresponding with the peaks shift in XRD test.

Study on Effect of Grinding Fluid Supply Parameters on Surface Integrity in Quick-Point Grinding for Green Manufacturing

2008 ◽  
Vol 53-54 ◽  
pp. 209-214 ◽  
Author(s):  
Shi Chao Xiu ◽  
Ya Dong Gong ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
High Speed ◽  
Point Contact ◽  
Green Manufacturing ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Fluid ◽  
Fluid Supply ◽  
High Speed Grinding ◽  
Grinding Power

In high and super-high speed grinding process, there is an airflow layer with high speed around the circle edge of the grinding wheel that hinders the grinding fluid into contact layer, namely, the air barrier effect. The speed of airflow layer is directly proportional to the square of the wheel speed. Quick-point grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding power. The edge effect of the air barrier is weakened because the thin CBN wheel is applied in the process. By the analysis of dynamic pressure and velocity distributions in the airflow layer around the wheel edge, the mathematic models of the flow and jet pressure of grinding fluid for effective supply in the process were established and the process of optimization calculation of the jet nozzle diameter for green manufacturing was also analyzed based on the thermodynamics and the technical character of quick-point grinding process. The quick-point grinding experiment for surface integrity influenced by grinding fluid supply parameters was performed.

Study on MQL in Point Grinding Process for Green Manufacturing

2010 ◽  
Vol 97-101 ◽  
pp. 2356-2360 ◽  
Author(s):  
Shu Dong Xiu ◽  
Zhi Jie Geng
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
Ground Surface ◽  
Green Manufacturing ◽  
Cooling Condition ◽  
Geometric Configuration ◽  
Grinding Process ◽  
Pressure Condition ◽  
Dry Grinding ◽  
Grinding Power

In point grinding process, the contact area of point grinding is much smaller than that of conventional cylindrical grinding under same conditions, so the grinding power and heat to measure is lower and the cooling condition is improved obviously. For green manufacturing, the point grinding process has the significance to reduce the consumption of grinding fluid and improve ground surface integrity and greenness. This study analyzes the geometric configuration of the contact area between wheel and workpiece in point grinding process, establishes the geometric and mathematic models of the contact area, and investigates the relations between the grinding parameters and the grinding power by the simulations. The MQL and semi-dry point grinding experiments are performed on the ground surface integrity. These investigations show that the MQL and semi-dry grinding can be achieved in point grinding process under less contact area and higher jet pressure condition for the high greenness demand.

Links Between Machining Parameters and Surface Integrity in Drilling Ni-Superalloy

2010 ◽  
Vol 112 ◽  
pp. 171-178 ◽  
Author(s):  
Vincent Dutilh ◽  
Gilles Dessein ◽  
Joël Alexis ◽  
Géraldine Perrin
Keyword(s):  
Surface Integrity ◽  
Tool Material ◽  
High Energy ◽  
Cutting Conditions ◽  
Nickel Base Superalloy ◽  
Machining Parameters ◽  
Hardness Tests ◽  
Metallurgical Analysis ◽  
Optical Profilometer ◽  
Nickel Base

In aerospace industry, the manufacturing of critical parts (high energy components) requires an important validation process to guarantee the quality of the produced parts, and thus their fatigue lifecycle. Globally, this validation consists in freezing the cutting conditions using metallurgical analysis or fatigue trials, and a test on the first article. This process is extremely complex and expensive. In this way establishing the correlation between the cutting conditions and the surface integrity will help us to optimize the manufacture of those parts. In this article, by the means of an experimental method, we define a domain of validation by combining the cutting conditions according to the classic criteria established by AFNOR E66-520 norm (Couple-Tool-Material) and the criteria of surface integrity for the drilling of a Nickel-base superalloy. The experimental device consists in drilling a Ø15.5 mm hole on a 3-axis milling centre instrumented by a 4 components Kistler dynamometer (Fx, Fy, Fz and Mz), a spindle power sensor “Watt-pilote” and three accelerometers placed following the directions X, Y and Z. Scanning Electron Microscopy (SEM) observations, micro-hardness tests and topographic measurements with an optical profilometer, are carried out to characterize the metallurgical state of the holes manufactured. Finally, correlations were respectively made between the cutting conditions, the recorded signals and the metallurgical state of the holes.

Influence of Coolant Application Direction on the Cutting Performance of Ceramic Tool in High-Speed Air-Jet-Assisted Machining of Inconel 718

2017 ◽  
Vol 749 ◽  
pp. 87-93
Author(s):  
Toshiyuki Obikawa ◽  
Masashi Yamaguchi
Keyword(s):  
Inconel 718 ◽  
High Speed ◽  
Cutting Speed ◽  
Cutting Performance ◽  
Necessary Condition ◽  
Nickel Base Superalloy ◽  
Ceramic Tool ◽  
Air Jet ◽  
Nickel Base ◽  
Base Superalloy

This paper describes the high speed air-jet-assisted machining of nickel-base superalloy with a SiC whisker reinforced alumina insert. This machining method showed already good performance in high speed machining of Inconel 718. In this paper, the influence of the application direction of coolant on the tool wear and tool life was investigated for obtaining much better cutting performance of the ceramic tool. The coolant was applied from the side of flank face with three different directions: two oblique directions from the end and side flank faces and the perpendicular direction to the cutting edges. In contrast, the application direction of the air jet was always perpendicular to the cutting edges. The experimental results showed that the best performance in the air-jet-assisted machining was obtained by applying coolant from the side of side flank at a cutting speed of 420 m/min and from the side of end flank at a cutting speed of 780 m/min. The necessary condition found for the best performance was that the size of notch wear was a little larger than that of flank wear.

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