Influence of rotational speed on mechanical features of thermally drilled holes in dual-phase steel

2018 ◽  
Vol 233 (5) ◽  
pp. 1614-1625 ◽  
Author(s):  
R Kumar ◽  
N Rajesh Jesudoss Hynes
Keyword(s):  
Surface Roughness ◽  
Rotational Speed ◽  
Outer Edge ◽  
Galvanized Steel ◽  
Drilling Process ◽  
Microstructural Investigation ◽  
Steel Material ◽  
Thermal Drilling ◽  
Microhardness And Microstructure ◽  
Lüders Band

Thermal drilling is a novel chipless sheet metal drilling process that uses a rotating thermal drill tool to pierce and form a bushing shape hole. In this work, thermal drilling process is successfully employed to drill the DP 600 grade–type galvanized steel with a thickness of 2 mm. The influence of different spindle rotational speeds such as 1600, 2000 and 2400 r/min on the formation of bushing height, surface roughness, microhardness and microstructure of the thermal-drilled holes are investigated in detail. Process parameters such as feed rate, thermal drill angle and workpiece thickness were held constant in order to explore the influence of rotational speed on the quality characteristics of the thermal drilling process. It has been found that the bushing height was improved with increasing of rotational speed, but the petal formation at the outer edge of the bush is decreased. Surface roughness tests indicate that the better surface quality drilled hole could be obtained at the highest rotational speed of 2400 r/min. The microstructural investigation confirmed that a new result of Lüders band marks was formed inside the thermal-drilled holes because high thermal stress and yielding of galvanized steel material.

Whirling vibration of drilling shaft in minimal quantity lubrication deep hole drilling using theoretical and experimental investigation

2014 ◽  
Vol 229 (13) ◽  
pp. 2433-2442
Author(s):  
Lingfei Kong ◽  
Han Niu ◽  
Xiaoli Hou ◽  
Qingfeng Wang
Keyword(s):  
Surface Roughness ◽  
Rotational Speed ◽  
Cutting Fluid ◽  
Hole Drilling ◽  
Experimental Investigations ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Minimal Quantity Lubrication ◽  
Minimal Quantity

Under the concept of safety, improving efficiency, or reducing costs in deep hole drilling, the effect of minimal quantity lubrication (MQL) on the dynamic characteristics of drilling shaft is analyzed. A model is presented to describe the pressure function of MQL cutting fluid during drilling process. This model is based on the compressible Reynolds equation in air/oil feature with nonlinearity, and the differential transformation theory is introduced to solve the time-dependent pressure equation satisfied with MQL cutting fluid. Further, with an emphasis on model development, experiments are performed to validate the correctness and effectiveness of the above methods. A series of experimental investigations are carried out on the whirling characteristics of drilling shaft when the rotational speed and drilling depth are changed. Additionally, the vibration trajectories of drilling shaft and the surface roughness of hole are detected under different experimental conditions such as MQL drilling or traditional drilling. The results show that the whirling trajectory of drilling shaft decreases significantly in MQL deep hole drilling but the surface roughness of machined hole is worse due to surface scratches or scales. Nevertheless, there exists an optimal rotational speed of drilling shaft to improve machining precision of hole surface. These results indicate that the MQL method has shown potential to be even more productive as compared to traditional drilling and that the proposed method in this paper can lay a foundation for investigating the dynamic stability of drilling shaft in MQL drilling.

scholarly journals Analysis and optimization of laser drilling process during machining of AISI 303 material using grey relational analysis approach

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
V. Chengal Reddy ◽  
Thota Keerthi ◽  
T. Nishkala ◽  
G. Maruthi Prasad Yadav
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Grey Relational Analysis ◽  
Pulse Frequency ◽  
Laser Drilling ◽  
Simultaneous Optimization ◽  
Fibre Laser ◽  
Drilling Process ◽  
Relational Analysis ◽  
Grey Relational

AbstractSurface roughness and heat-affected zone (HAZ) are the important features which influence the performance of the laser-drilled products. Understanding the influence of laser process parameters on these responses and identifying the cutting conditions for simultaneous optimization of these responses are a primary requirement in order to improve the laser drilling performance. Nevertheless, no such contribution has been made in the literature during laser drilling of AISI 303 material. The aim of the present work is to optimize the surface roughness (Ra) and HAZ in fibre laser drilling of AISI 303 material using Taguchi-based grey relational analysis (GRA). From the GRA methodology, the recommended optimum combination of process parameters is flushing pressure at 30 Pa, laser power at 2000 W and pulse frequency at 1500 Hz for simultaneous optimization of Ra and HAZ, respectively. From analysis of variance, the pulse frequency is identified as the most influenced process parameters on laser drilling process performance.

scholarly journals Effects of hybrid Al2O3–CuO nanofluids on surface roughness and machining forces during turning AISI 4340

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Shahin Haghnazari ◽  
Vahid Abedini
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Rotational Speed ◽  
Minimum Quantity Lubrication ◽  
Weight Percent ◽  
Cutting Fluid ◽  
Hybrid Nanofluid ◽  
Workpiece Material ◽  
Machining Forces ◽  
Aisi 4340

AbstractThis paper presents an effort to model the process parameters involved in turning of alloy steel AISI 4340 workpiece material with Al2O3 and CuO hybrid nanofluids using the minimum quantity lubrication (MQL) method. In this paper, the effect of mixing two nanoparticles (Al2O3 and CuO) with different weight percent in environmentally friendly water-based cutting fluid, the rotational speed, and the feed rate has been investigated on the surface roughness and the machining forces using the response surface method. The results of the experiments show that the hybrid nanofluid containing 0.75 CuO with 0.25 Al2O3 has the best output for the machining forces and the surface roughness. Also, in the best composition of the nanoparticles (0.75 CuO with 0.25 Al2O3), the lowest value of machining forces has been achieved at a feed rate of 0.08 mm per revolution and the rotational speed 1000 rpm as well as the lowest value of the surface roughness at a feed rate of 0.08 mm per revolution and the rotational speed 710 rpm.

Calculating the parameters of the thermal drilling process

1969 ◽  
Vol 5 (1) ◽  
pp. 26-31 ◽  
Author(s):  
A. P. Dmitriev ◽  
I. D. Kill' ◽  
A. D. Sukhanov ◽  
O. N. Tret'yakov
Keyword(s):  
Drilling Process ◽  
Thermal Drilling

Analysis of Torsional Stick-Slip Situations from Recorded Downhole Rotational Speed Measurements

2021 ◽  
pp. 1-15
Author(s):  
Eric Cayeux ◽  
Adrian Ambrus ◽  
Lars Øy ◽  
Arvid Helleland ◽  
Svein Brundtland ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Rotational Velocity ◽  
The Other ◽  
Drilling Process ◽  
Stick Slip ◽  
Torsional Oscillations ◽  
Direct Observations ◽  
New Information ◽  
Weight On Bit ◽  
Downhole Measurements

Summary The use of recorded downhole rotational speed measurements with a bandwidth up to 9 Hz gives new insights into the conditions under which stick-slip torsional oscillations occur. Observations made while drilling two reservoir sections have shown that, out of all the stick-slip situations identified, 72% of them for one well and 64% for the other well occurred in off-bottom conditions. In these off-bottom conditions, stick-slip was systematically observed while starting the topdrive (TD) until a sufficiently high TD rotational velocity was requested. For these two sections, off-bottomstick-slip was either related to using TD speeds below 120 rev/min or to reaming down during reciprocation procedures. In on-bottom conditions, stick-slip events occurred predominantly when the TD speed was less than 120 rev/min (53 and 32% of the on-bottom cases) but also in association with downlinking to the rotary steerable system (RSS) (23 and 46% of the on-bottom cases), and this, even though the TD speed was larger than 120 rev/min. These on-bottomstick-slip situations did not necessarily occur at a very high weight on bit (WOB) because 98% of them for one well and 46% for the other well took place when the WOB was lower than 10 ton. Downhole measurements have shown that when the drillstring is subject to strong stick-slip conditions, the downhole rotational speed changes from stationary to more than 300 rev/min in just a fraction of a second. Direct observations of downhole rotational speed at high frequency help in discovering conditions that were not suspected to lead to large torsional oscillations. This new information can be used to improve drilling operational procedures and models of the drilling process, therefore enabling increased drilling efficiency.

scholarly journals Effects of Microstructure, Mechanical and Physical Properties on Machinability of Graphite Cast Irons

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 285 ◽  
Author(s):  
Jiangzhuo Ren ◽  
Fengzhang Ren ◽  
Fengjun Li ◽  
Linkai Cui ◽  
Yi Xiong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Roughness ◽  
Standard Deviation ◽  
Cutting Force ◽  
Volume Fraction ◽  
Internal Surface ◽  
Drilling Process ◽  
Turning Process ◽  
Cast Irons ◽  
Mechanical And Physical Properties

Flake (FGI) and spheroidal (SGI) graphite cast irons are often used to produce workpieces, which often need to be machined. Machinability differences under various machining methods are the basis for choosing machining equipment and technology. In this work, FGI and SGI were used to produce tractor front brackets, and the machinability of both materials under turning and drilling processes was compared. The machinability (turning and drilling ability) has been evaluated in terms of machining load, chips shape, surface roughness, and tool temperature. The influence of materials microstructure and thermal conductivity on the machinability was analyzed. In the turning process, the cutting force and its standard deviation of the FGI were larger than the SGI due to the higher volume fraction of pearlite. The surface roughness was similar in both materials. In the drilling process, the even action of the friction and cutting force on the bit turned into similar drilling loads for both materials. Higher friction and lower thermal conductivity caused a higher bit temperature in SGI drilling compared to FGI. The chip breaking was worse in SGI drilling, where the longer chips scratched the internal surface of the holes, resulting in the higher surface roughness.

scholarly journals Effect of Friction Stir Processing on Microstructural, Mechanical, and Corrosion Properties of Al-Si12 Additive Manufactured Components

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85 ◽  
Author(s):  
Ghazal Moeini ◽  
Seyed Vahid Sajadifar ◽  
Tom Engler ◽  
Ben Heider ◽  
Thomas Niendorf ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Micro Hardness ◽  
Corrosion Properties ◽  
Microstructural Investigation ◽  
Friction Stir ◽  
Size Refinement ◽  
Hardness Values

Additive manufacturing (AM) is an advanced manufacturing process that provides the opportunity to build geometrically complex and highly individualized lightweight structures. Despite its many advantages, additively manufactured components suffer from poor surface quality. To locally improve the surface quality and homogenize the microstructure, friction stir processing (FSP) technique was applied on Al-Si12 components produced by selective laser melting (SLM) using two different working media. The effect of FSP on the microstructural evolution, mechanical properties, and corrosion resistance of SLM samples was investigated. Microstructural investigation showed a considerable grain refinement in the friction stirred area, which is due to the severe plastic deformation and dynamic recrystallization of the material in the stir zone. Micro-hardness measurements revealed that the micro-hardness values of samples treated using FSP are much lower compared to SLM components in the as-built condition. This reduction of hardness values in samples treated with FSP can be explained by the dissolution of the very fine Si-phase network, being characteristic for SLM samples, during FSP. Surface topography also demonstrated that the FSP results in the reduction of surface roughness and increases the homogeneity of the SLM microstructure. Decreased surface roughness and grain size refinement in combination with the dissolved Si-phase network of the FSP treated material result in considerable changes in corrosion behavior. This work addresses the corrosion properties of surface treated additive manufactured Al-Si12 by establishing adequate microstructure-property relationships. The corrosion behavior of SLM-manufactured Al-Si12 alloys is shown to be improved by FSP-modification of the surfaces.

scholarly journals Change of the Properties of Steel Material of the Roller Cone Bit Due to the Influence of the Drilling Operational Parameters and Rock Properties

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5949
Author(s):  
Jurij Šporin ◽  
Tilen Balaško ◽  
Primož Mrvar ◽  
Blaž Janc ◽  
Željko Vukelić
Keyword(s):  
Structural Changes ◽  
Simultaneous Thermal Analysis ◽  
Rock Properties ◽  
Drilling Process ◽  
Drill Bit ◽  
Operational Parameters ◽  
Rock Materials ◽  
Steel Material ◽  
Drilling Parameters ◽  
Bit Life

The breakdown of the drill bit or rapid decrease of the rate of penetration during the drilling process results in a delay in the progress of drilling. Scientists and engineers are increasingly focusing on research to extend the bit life and improve the drilling rate. In our work, “in situ” drilling parameters were monitored during the drilling process with the roller cone drill bit IADC 136, diameter 155.57 mm (6 1/8"). After drilling, the bit was thoroughly examined to determine the damage and wear that occurred during drilling. The following modern and standardized investigative methods were used: an analysis of rock materials and an analysis of micro and macrostructure materials of the roller cone bit. Analyses were carried out using optical and electron microscopy, a simultaneous thermal analysis of materials of drill bit, analysis of the chemical composition of materials of drill bit, and a determination of the geomechanical parameters of rock materials. The resulting wear, local bursts, and cracks were quantitatively and qualitatively defined and linked to the drilling regime and the rock material. The results of our investigation of the material of the roller cone bit can serve as a good base for the development of new steel alloys, which can resist higher temperatures and enable effective drilling, without structural changes of steel material.

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