Characterization of micro hole on super alloy GH4037 and stainless steel 304 by millisecond-pulsed Nd:YAG laser processing

2021 ◽  
Vol 11 (12) ◽  
pp. 1975-1987
Author(s):  
Liang Wang ◽  
Rong Guan ◽  
Qunyong Zhang ◽  
Kaibo Xia ◽  
Naifei Ren
Keyword(s):  
Stainless Steel ◽  
Pulse Duration ◽  
Pulse Energy ◽  
Recast Layer ◽  
Stainless Steel 304 ◽  
Micro Holes ◽  
Micro Hole ◽  
Simulation Results ◽  
Super Alloy

In this study, both super alloy GH4037 and stainless steel 304 were selected as experimental materials to be processed by LASERTEC 80 PowerDrill three-dimensional solid laser machining center. The structure of the micro hole was researched by 3D Laser Scanning Confocal Microscope and Scanning Electron Microscope (SEM). Meanwhile, The holes taper, entrance and exit ends diameter, microcrack, recast layer, orifice deposits and the heat affected zone (HAZ) were also investigated. The single factor experimental method was used to research the influences of defocusing amount, pulse energy, repetition frequency, and pulse duration on quality of micro holes. Experimental results indicated that the holes entrance and exit ends diameter enlarged with increased pulse energy from 3.4 J to 4.2 J. The entrance and exit ends diameter of holes decreased with increased pulse duration from 0.5 ms to 2.5 ms. Besides, the variation of holes diameter and taper were more obvious with repetition frequency changing from 10 Hz to 30 Hz, and variation range for the entrance and exit ends diameters and taper were not obvious with increased defocusing amount from −2 mm to 2 mm. The herein results indicated that pulse energy was one of the most significant influencing elements, and higher pulse energy could bring about lower hole taper within a certain range. Meanwhile, shorter pulse duration reduced splash and debris of holes surface. The recast layer, micro crack and HAZ were existed in the both kinds of experimental materials. Moreover, the microcrack and recast layer on holes wall of GH4037 were less than those of 304, and the HAZ in drilling hole for GH4037 was more than that of 304. The experimental results for the holes size were compared with corresponding simulation results under different defocusing amount respectively, which verified the accuracy of simulation results. Combining the above factors, the quality of micro holes drilling on super alloy GH4037 was better than stainless steel 304.

Study on Recast Phenomenon in Processing of Micro-Hole with Millisecond Laser

2012 ◽  
Vol 459 ◽  
pp. 315-319 ◽  
Author(s):  
Ke Dian Wang ◽  
Wen Qiang Duan ◽  
Xue Song Mei ◽  
Wen Jun Wang
Keyword(s):  
Stainless Steel ◽  
Titanium Alloy ◽  
Pulse Width ◽  
Peak Power ◽  
Recast Layer ◽  
Hole Depth ◽  
Maximum Peak ◽  
Blind Hole ◽  
Micro Hole ◽  
Millisecond Laser

The experiments of micro-hole ablation are conducted firstly on titanium alloy Ti-6Al-4V with Nd: YAG millisecond laser. A significant factor which affects the depth of blind hole is found: the depth of recast material. This paper closely examines the regularity of recast depth varying with laser parameters, discovering that the ratio of recast depth to the entire hole depth decreases as pulse width decreases, and increases as peak power decreases. Verification experiment is conducted on stainless steel 1Cr13, eventually micro-hole with very thin recast layer is drilled when the maximum peak power and the minimum pulse width of the present millisecond laser are used.

scholarly journals Development of a Novel Hybrid Unified Viscoplastic Constitutive Model

2015 ◽  
Author(s):  
Luis A. Varela J. ◽  
Calvin M. Stewart
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Hybrid Model ◽  
Material Constant ◽  
Inelastic Behavior ◽  
Hastelloy X ◽  
Material Constants ◽  
Stainless Steel 304 ◽  
Simulation Results ◽  
Optimal Material

Hastelloy X and stainless steel 304 are alloys widely used in industrial gas turbines components, petrochemical industry and energy generation applications; In the Pressure Vessel and Piping (PVP) industries they are used in nuclear and chemical reactors, pipes and valves applications. Hastelloy X and stainless steel 304 are favored for these types of applications where elevated temperatures are preferred for better systems’ efficiencies; they are favored due to its high strength and corrosion resistance at high temperature levels. A common characteristic of these alloys, is its rate-dependent mechanical behavior which difficult the prediction of the material response for design and simulation purposes. Therefore, a precise unified viscoplastic model capable to describe Hastelloy X and stainless steel 304 behaviors under a variety of loading conditions at high temperatures is needed to allow a better and less conservative design of components. Numerous classical unified viscoplastic models have been proposed in literature, to predict the inelastic behavior of metals under extreme environments. Based on Miller and Walker classical unified constitutive models a novel hybrid unified viscoplastic constitutive model is introduced in the present work, to describe the inelastic behavior caused by creep and fatigue effects at high temperature. The presented hybrid model consists of the combination of the best aspects of Miller and Walker model constitutive equations, with the addition of a damage rate equation which provides a description of the damage evolution and rupture prediction capabilities for Hastelloy X and stainless steel 304. A detailed explanation on the meaning of each material constant is provided, along with its impact on the hybrid model behavior. Material constants were calculated using the recently developed Material Constant Heuristic Optimizer (MACHO) software, to ensure the use of the optimal material constants values. This software uses the simulated annealing algorithm to determine the optimal material constants in a global surface, by comparing numerical simulations to an extensive database of experimental data. To validate the capabilities of the proposed hybrid model, numerical simulation results are compared to a broad range of experimental data at different stress levels and strain amplitudes; besides the consideration of two alloys in the present work, would demonstrate the model’s capabilities and flexibility to model multiple alloys behavior. Finally a quantitative analysis is provided to determine the percentage error and coefficient of determination between the experimental data and numerical simulation results to estimate the efficiency of the proposed hybrid model.

Dissimilar Materials Laser Welding between Stainless Steel 304 and Thermoplastics

2016 ◽  
Vol 719 ◽  
pp. 142-148 ◽  
Author(s):  
Rattana Borrisutthekul ◽  
Anchalee Saengsai ◽  
Pusit Mitsomwang
Keyword(s):  
Stainless Steel ◽  
Welding Speed ◽  
Dissimilar Materials ◽  
Decomposition Temperature ◽  
Lap Joint ◽  
Joint Configuration ◽  
Focal Position ◽  
Stainless Steel 304

Nowadays, dissimilar materials welding, especially between metal to plastics, has been become the hottest issue. The objective of the study is to investigate the effects of physical properties of plastics on the weldability and the quality of the dissimilar materials welding between SUS304 stainless steel and plastics. In experiment, the lap joint configuration with SUS304 put on the top was applied. The welding speed, focal position, and keeping period of weld after welding were varied. The results indicated that the decomposition temperature of plastics affected both weldability and quality of joint after welding. Moreover, crazing was a prominent property to be considered for long-term use of the dissimilar materials welding as the specimen could fracture by itself after a period of time without any application of the external load.

Comparative Research on the Quality of Micro Hole in Superalloy GH2135 and Stainless Steel 420J1 by Laser Processing

2016 ◽  
Vol 703 ◽  
pp. 27-33
Author(s):  
Liang Wang ◽  
Nai Fei Ren ◽  
Yun Long Wang ◽  
Lin Zhong Zhu
Keyword(s):  
Stainless Steel ◽  
Pulse Energy ◽  
Laser Processing ◽  
Pulse Width ◽  
Laser Scanning ◽  
Short Pulse ◽  
Test Method ◽  
Repetition Frequency ◽  
Orifice Diameter

Both superalloy GH2135 and stainless steel 420J1 were used as test materials to be processed by LASERTEC 80 PowerDrill three-dimensional solid laser processing center. The microstructure of the hole was investigated by super depth of field microscope and laser scanning microscope. The front and back orifice diameter, orifice deposits and thermal effect of accumulation zone were studied. The single factor test method was used to study the influence of pulse energy, pulse width and repetition frequency on the quality of micro holes. The results showed that the front and back diameter of the holes all increase with the increase of pulse energy from 0.4J-3.9J. And the front and back aperture are increase with the increase of pulse width from 0.9ms-1.9ms. Meanwhile, the variation of the aperture and pore taper is more noticeable with the repetition frequency changed from 10Hz-60Hz. The results revealed that pulse energy is one of the biggest influence factors, large pulse energy can lead to small hole taper within a certain range, and short pulse width can reduce orifice debris and splash. Both the recast layer and microcrack were existed in the two kinds of metal materials. The quality of holes drilling in GH2135 is better than 420J1.

Machining and Characterization of Deep Micro Holes on Super Alloy Processed by Millisecond Pulsed Laser

2016 ◽  
Vol 703 ◽  
pp. 34-38 ◽  
Author(s):  
Yun Long Wang ◽  
Lin Zhong Zhu ◽  
Cai Yan Chen ◽  
Zhi Chen Liu ◽  
Wei Xin Ren ◽  
...  
Keyword(s):  
Laser Power ◽  
Laser Scanning ◽  
Pulsed Laser ◽  
Processing System ◽  
Longitudinal Section ◽  
Recast Layer ◽  
Numerical Control ◽  
Micro Cracks ◽  
Micro Holes ◽  
Super Alloy

In this study, a series of deep micro holes were machined on thick GH4169 super alloy by the trepan drilling, using a millisecond pulsed laser which equipped to the numerical control processing system. The microstructure of the holes including surface and longitudinal morphologies, diameter, taper, circularity, micro cracks and recast layer were systematically characterized. The surface morphology and the longitudinal section of the drilled holes were observed by Scanning Electron Microscope and 3D Laser Scanning Confocal Microscope. The method of Minimum circumcircle method was employed to evaluate the entrance and exit end circularity. The results showed that the melt and spattering accumulating around the holes decreased with the augment of laser power. The diameter of the entrance showed an increasing tendency with the growing of laser power, but the exit end was not seriously affected by the power. The micro cracks and recast layer could be found obviously, the micro cracks appeared in those zones which thermal stress concentrated, the thickness of recast layer is about 20μm and the taper and circularity were optimized at a laser power of 80-100W.

Experimental Investigation on Fiber Laser Welding Stainless Steel 304 to Super Alloy GH3128

Applied laser ◽  
2012 ◽  
Vol 32 (2) ◽  
pp. 108-111
Author(s):  
周春阳 Zhou Chunyang ◽  
吴世凯 Wu Shikai ◽  
肖荣诗 Xiao Rongshi
Keyword(s):  
Experimental Investigation ◽  
Stainless Steel ◽  
Laser Welding ◽  
Fiber Laser ◽  
Fiber Laser Welding ◽  
Stainless Steel 304 ◽  
Super Alloy ◽  
Welding Stainless Steel

The tool-wear characteristics of flexible printed circuit board micro-drilling and its influence on micro-hole quality

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 162-169 ◽  
Author(s):  
Lijuan Zheng ◽  
Chengyong Wang ◽  
Xin Zhang ◽  
Xin Huang ◽  
Yuexian Song ◽  
...  
Keyword(s):  
Tool Wear ◽  
Circuit Board ◽  
Hole Quality ◽  
Content Type ◽  
Wear Characteristics ◽  
Printed Circuit ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Hole

Purpose Micro-holes are drilled and plated in flexible printed circuit boards (FPCs) for connecting circuits from different layers. More holes, with diameters smaller than 0.3 mm, are required to be drilled in smaller areas with flexible circuits’ miniaturization. The micro-hole quality of micro-drilling is one of the biggest issues of the flexible circuit manufacturers’ production. However, it is not easy to control the quality of micro-holes. The purpose of this study was to conduct research on the tool wear characteristics of FPC drilling process and its influence on micro-hole quality to improve the micro-hole quality of FPC. Design/methodology/approach The tool-wear characteristics of micro-drills after FPC drilling were observed. The influence of spindle speed, feed rate, number of drilled holes and entry board materials on tool-wear was analyzed. The hole qualities of FPC micro-drilling were measured and observed. The relationship between tool-wear and hole quality was analyzed. Findings The result showed that the tool-wear characteristics of FPC micro-drilling was similar to the tool-wear characteristics of rigid printed circuit board (RPC) micro-drilling. Abrasive wear occurred on both the main cutting edges and the chisel edges of micro-drills, even though there was no glass fiber reinforcing the cloth inside FPC. Resin adhesion was observed on the chisel edge. The influence of feed and number of drilled holes on tool-wear was significant. Tool-wear significantly influences the hole quality of FPC. Tool-wear will largely decrease the hole position accuracy of FPC micro-holes. Tool-wear will increase the thickness of PI nail heads and the height of exit burrs. Fracture was the main difference between tool wear of FPC and RPC micro-drilling. Resin adhesion of RPC was much more severe than FPC micro-drilling. Increasing the spindle speed properly may improve tool life and hole quality. Originality/value The technology and manufacturing of FPC has been little investigated. Research on micro-drilling FPC and research data is lacking so far. The micro-hole quality directly affects the reliability of FPC. Thus, improving the micro-hole quality of FPC is very important.

scholarly journals A New Method to Assess Fiber Laser Welding Quality of Stainless Steel 304 Based on Machine Vision and Hidden Markov Models

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 130633-130646
Author(s):  
Xin Tang ◽  
Ping Zhong ◽  
Lingling Zhang ◽  
Jun Gu ◽  
Zhaopeng Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Fiber Laser ◽  
Hidden Markov Models ◽  
Markov Models ◽  
Hidden Markov ◽  
Welding Quality ◽  
Fiber Laser Welding ◽  
Stainless Steel 304

Design and Numerical Simulation of a Three-Dimensional Nozzle Microstructured Mixer

2007 ◽  
Vol 339 ◽  
pp. 343-347 ◽  
Author(s):  
Min Qiang Pan ◽  
Yong Tang ◽  
Long Sheng Lu ◽  
Zhen Ping Wan ◽  
X.K. Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Stainless Steel ◽  
Flow Visualization ◽  
Steel Sheet ◽  
Three Dimensional ◽  
Machining Process ◽  
Stainless Steel Sheet ◽  
Local Surface ◽  
Micro Hole ◽  
Simulation Results

A passive microstructured mixer based on micro-ploughing technology with a multi-tooth tool is proposed. The mixer uses multiple three-dimensional nozzles to split one of the liquids into several micro-plumes. The fins on the surface of the nozzles induce a second liquid to generate turbulence around the local surface of the fins. The machining mechanism for fabricating 3D nozzles on a stainless steel sheet by micro-ploughing technology with a multi-tooth tool was studied. The machining process mainly involves four stages: tool-feeding, fin-forming, micro-hole-forming and tool-retracting. Simulation and flow visualization were used to evaluate its performance. The simulation results show the fin structure can induce local surface turbulence. The flow visualization indicates that when the flux is between 0.5ml/s and 3ml/s, the two liquids are fully mixed in 1second.

The Research on the Action Modes of Laser Shock Wave Affected by Different Confinement Overlays

2011 ◽  
Vol 403-408 ◽  
pp. 2667-2670
Author(s):  
Yin Qun Hua ◽  
Rui Fang Chen ◽  
Yun Xia Ye ◽  
Hai Xia Liu
Keyword(s):  
Shock Wave ◽  
Stainless Steel ◽  
Pulse Duration ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Stainless Steel 304 ◽  
Action Modes ◽  
Laser Shock Wave ◽  
Shock Processing ◽  
Nd:Glass Laser

The liquid confinement medium (LCM) and the free confinement medium (FCM) made by ourselves were used as confinement overlays of laser shock processing (LSP) respectively, stainless steel 304 was shocked by Nd:Glass laser. The parameters of LSP are the wavelength of 1.06μm, the pulse duration of 20ns, and output energy of 35~40J. The laser was focused on a spot of Ф5mm. Firstly, the profiles of shocked regions of samples were measured by Taylor Hobson admeasuring apparatus, in which two different confinement mediums are used by LSP. Secondly, the ruinous behavior of the free confinement overlays induced by laser shock wave is observed and analyzed. Analyzed and compared with the experiments results, it is discovered that the effects of LSP are different with using different confinement mediums.

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