scholarly journals Influence of Local Temperature Changes on the Material Microstructure in Abrasive Water Jet Machining (AWJM)

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5399
Author(s):  
Sławomir Spadło ◽  
Damian Bańkowski ◽  
Piotr Młynarczyk ◽  
Irena M. Hlaváčová

This article considers effects of local heat transfer taking place insteel cutting by abrasive water jet machining (AWJM). The influence of temperature changes during AWJM has not been investigated thoroughly. Most studies on AWJM suggest that thermal energy has little or no effect on the material cut. This study focused on the analysis of the material microstructure and indentation microhardness in the jet impact zone and the adjacent area. The structure features revealed through optical metallography and scanning microscopy suggest local temperature changes caused by the impact of the abrasive water jet against the workpiece surface. From the microscopic examinationand hardness tests, it is clear that, during the process, large amounts of energy were transferred locally. The mechanical stress produced by the water jet led to plastic deformation at and near the surface. This was accompanied by the generation and transfer of large amounts of heat resulting in a local rise in temperature to 450 °C or higher.

2014 ◽  
Vol 1017 ◽  
pp. 228-233 ◽  
Author(s):  
Yong Wang ◽  
Hong Tao Zhu ◽  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Peng Yao ◽  
...  

Abrasive water jet machining is considered as a promising technique in hard and brittle material processing. This paper studies the erosion performance of the alumina ceramics in the different process parameters. In the erosion experiments, alumina ceramics wafers were eroded by the abrasive waterjet machining. The single factor experiments were carried out to understand the effect of different process parameters (jet impact angle, standoff distance, water pressure, abrasive particle diameter) on the material removal rate (MRR), the removal depth and surface roughness (Ra). The experimental results can provide guidance for alumina ceramics abrasive water jet cutting and polishing.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7768
Author(s):  
Adam Štefek ◽  
Martin Tyč

Several titanium alloys, i.e., grade 2 Ti, Ti6Al4V and NiTi alloy, prepared by selected deformation procedures were subjected to abrasive water jet (AWJ) cutting and subsequently analysed. The study describes samples’ preparations and respective material structures. The impact of deformation processing of the selected alloys on the declination angle during cutting, and the results of measurements of surface wall quality performed for the selected samples at the Department of Physics of Faculty of Electrical Engineering and Computer Science at VŠB–Technical University of Ostrava, are presented and discussed, as are also the influences of structural features of the processed titanium alloys on surface qualities of the investigated samples. The results showed that the highest resistance to AWJ machining exhibited the Ti6Al4V alloy prepared by forward extrusion. Its declination angle (recalculated to the thickness 10 mm to compare all the studied samples) was 12.33° at the traverse speed of 100 mm/min, pumping pressure of 380 MPa, and abrasive mass flow rate of 250 g/min.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jialiang Liu ◽  
Yujie Zhu ◽  
Yongzhi Xue ◽  
Hao Sun

Abrasive water jet (AWJ) breaking technology is suitable for the maintenance and repair of concrete structures, generating minimal dust, low tool wear, and no vibrations or selective destruction. The failure features and mechanisms of concrete subjected to AWJ impact are fundamental issues of AWJ breaking technology, which are also related to the safety and quality of engineering construction. Based on computed tomography (CT), scanning electron microscopy (SEM), and image processing technology, this paper studied the fragmentation pattern and removal mechanism of concrete under AWJ impact. The general failure characteristics and crack propagation law of concrete subjected to AWJ impact were described through AWJ impact concrete tests. The spatial distribution of damage in concrete subjected to AWJ impact can be divided into the intensive action zone, the transition zone, and the weak action zone. The removal mechanism of AWJ was discussed by comparing the impact performance of a pure water jet (PWJ) system. The results indicate that abrasive particles can cause cliff-shaped fracture and lip-shaped distortion in the aggregate part and flat fracture surface in the matrix part. There is no obvious crack in the interfacial transition zone (ITZ) due to the weakening of the water wedge effect.


2018 ◽  
Vol 53 (20) ◽  
pp. 2909-2924 ◽  
Author(s):  
Ajit Dhanawade ◽  
Shailendra Kumar

Traditional machining of carbon epoxy composite material is difficult due to excessive tool wear, excessive stresses and heat generation, delamination, high surface waviness, etc. In the present paper, research work involved in the experimental study of abrasive water jet machining of carbon epoxy composite material is described. The aim of present work is to improve surface finish and studying defects in machined samples. Taguchi's orthogonal array approach is used to design experiments. Process parameters namely hydraulic pressure, traverse rate, stand-off distance and abrasive mass flow rate are considered for this study. Analysis of machined surfaces and kerf quality is carried out using scanning electron microscope to evaluate microscopic features. Further, the effect of machining parameters on surface roughness is investigated using analysis of variance approach. It is found that traverse rate and pressure are most significant parameters to control surface roughness. Optimization of process parameters is performed using grey relational analysis. Thereafter, confirmation tests are carried out to verify the improvement in the surface quality with optimum set of process parameters. It is found that surface finish of machined samples is improved by 10.75% with optimum levels of process parameters. Defects like delamination, fiber pull-out and abrasive embedment are also studied using SEM. It is observed that delamination and fiber pull-out are prominent in samples machined at low pressure and high traverse rate.


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