Gas-Jet-Assisted Keyhole Laser Welding of Q235 Mild Steel

2012 ◽  
Vol 629 ◽  
pp. 180-186 ◽  
Author(s):  
Xian Feng Shen ◽  
Wen Hua Teng ◽  
Wen Rong Huang ◽  
Chao Xu
Keyword(s):  
Laser Welding ◽  
Penetration Depth ◽  
Gas Jet ◽  
Maximum Temperature ◽  
Maximum Increase ◽  
Ship Building ◽  
Key Factor ◽  
Columnar Grains ◽  
Series Of Experiments ◽  
Conventional Laser

Increases in the penetration depth of laser welding has gained undoubted interest, especially in the aerospace, power station, ship building, and other heavy industries. Gas-jet-assisted keyhole laser welding is a prospective method for improving the penetration of conventional laser welding. A series of experiments using this method were conducted with different parameters of the assisted gas jet and the welding speed. The microstructures of weld joints were observed using optical microscopy, and microhardness was also measured. The investigation results showed that the penetration depth of this laser welding increased by more than 20%, with a maximum increase of approximately 26%, at different welding speeds, while the weld width was significantly reduced compared with that of conventional laser welding. The key factor affecting the penetration increase is the interaction between the assisted gas jet and the plasma. The penetration increase was determined by the distribution and amplitude of the assisted gas jet at the position of the keyhole orifice. The grain in the heat-affected zone (HAZ) and weld seam of gas-jet-assisted keyhole laser welding was finer, and the number of columnar grains was also significantly reduced. The microhardness of the HAZ for the assisted gas jet was much lower, and more pearlite and less martensite were observed this zone. This was caused by the reduced maximum temperature of the molten pool, reduced high-temperature residence time, increased cooling rate, and diminished temperature gradient with the introduction of the assisted gas jet.

Experimental Investigation on Rotary Punching by the Compression of Polyurethane Pad

2014 ◽  
Vol 941-944 ◽  
pp. 1802-1807 ◽  
Author(s):  
Qian Liu ◽  
Jing Tao Han ◽  
Jing Liu ◽  
Xiao Xiong Wang
Keyword(s):  
Penetration Depth ◽  
Process Parameters ◽  
High Load ◽  
Large Area ◽  
Bear Capacity ◽  
Hole Edge ◽  
Quality Degradation ◽  
Series Of Experiments ◽  
Blanking Process ◽  
The Relationship

Rotary punching is a sheet metal blanking process which utilizes shearing tools fixed to a pair of rollers. The polyurethane pad is adopted as the die instead of rigid mold because it has the advantages of wide hardness range and high load-bear capacity. Due to the application of polyurethane pad, the surrounding region adjacent to the pierced hole will occur to plastically deform and deflect, which greatly differs from that in the conventional blanking. In this paper, the effects of blank material and thickness, polyurethane hardness, punch penetration depth on deformation behavior were mathematically analyzed and modeled, and then a series of experiments through varying process parameters were conducted to validate the relationship between process parameters and product quality. The degree of sample deflection was exactly measured by scanning electron microscope (SEM). The results show that the deformed area varies with different blank elongations and increases with increasing blank thickness for a given material. When polyurethane pad with low hardness level is employed, it results in large area deformation and quality degradation. Moreover, the deflection degree around the hole edge becomes more severe along with punch penetration, but the penetration depth along blank thickness is not in proportion to the amount of punch advancement.

Characteristics of Plasma in Gas-Jet-Assisted Keyhole Laser Welding of 1Cr18Ni9Ti

Applied laser ◽  
2013 ◽  
Vol 33 (5) ◽  
pp. 510-514
Author(s):  
沈显峰 Shen Xianfeng ◽  
滕文华 Teng Wenhua ◽  
许超 Xu Chao ◽  
张伟超 Zhang Weichao ◽  
刘世杰 Liu Shijie
Keyword(s):  
Laser Welding ◽  
Gas Jet

scholarly journals Moisture Buffering of Multilayer Internal Wall Assemblies at the Micro Scale: Experimental Study and Numerical Modelling

2019 ◽  
Vol 9 (16) ◽  
pp. 3438 ◽  
Author(s):  
Dobrosława Kaczorek
Keyword(s):  
Penetration Depth ◽  
Buffering Capacity ◽  
Internal Wall ◽  
Simplified Method ◽  
Buffer Value ◽  
Series Of Experiments ◽  
Overall Performance ◽  
Wall Assembly ◽  
Moisture Buffering ◽  
Moisture Buffer Value

In this paper, a series of experiments assessing the moisture buffer value (MBV) of four internal wall assembly samples made from hygroscopic materials was performed. A modified Nordtest protocol was used. Moisture buffer values of all the investigated wall assemblies, with varying moisture loads in the range of 50% to 80%, showed a moderate moisture buffer value (MBV: 0.5–1.0 (g·m−2·%RH−1)). The results showed that in a wall assembly where the MBV of the whole assembly is lower than the MBV of the outer layers, the moisture-buffering capacity of the inner layer is untapped. Outer layers affect inner layers by changing their moisture-buffering capacity, which in turn changes the overall performance of the whole assembly. In addition, it was observed that if the penetration depth value of the outer layer is greater than its thickness, vapour reaches into the deeper layer and wall assemblies made of layers with materials characterized by a lower value of penetration depth reach steady state more slowly. The WUFI Pro tool was used to compare the simulated and experimental results. Despite the discrepancies between these results, it offers a simplified method, helping designers make decisions about which materials to choose to improve the moisture-buffering effect.

Investigations on in-process control of penetration depth for high-power laser welding of thick steel-aluminum joints

2019 ◽  
Vol 31 (2) ◽  
pp. 022418 ◽  
Author(s):  
Rabi Lahdo ◽  
Oliver Seffer ◽  
Stefan Kaierle ◽  
Ludger Overmeyer
Keyword(s):  
Process Control ◽  
Laser Welding ◽  
Penetration Depth ◽  
High Power ◽  
High Power Laser ◽  
Power Laser ◽  
Thick Steel

Synthesis and Properties of Cellulose Stearate

2011 ◽  
Vol 228-229 ◽  
pp. 919-924 ◽  
Author(s):  
Feng Yuan Huang
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Glass Transition ◽  
Transition Temperature ◽  
1H Nmr ◽  
Homogeneous System ◽  
Molar Ratio ◽  
Maximum Temperature ◽  
Key Factor ◽  
Ft Ir

Cellulose Stearate (CS) was synthesized by acylating microcrystalline cellulose (MCC) in homogeneous system with p-toluenesulfonyl chloride (Tos-Cl) and stearic acid (SA). The reactive conditions were discussed. The molar ratio of AGU:SA:Tos-Cl was the key factor which affected the degree of substitution (DS) of CS. In the present paper, CSs with DS ranging from 0.64 to 2.35 were prepared under mild condition. The structure of CS was characterized by FT-IR and 1H-NMR, and DS of CS was determined by traditional saponification method and 1H-NMR, respectively. The solubility of CS was also investigated; the results showed that the higher DS of CS was, the easier CS dissolved in organic solvents. The thermal analysis was measured with DSC, and the results indicated that the glass transition temperature (Tg) and the maximum temperature of thermal decomposition (Tmax) of CS were dependent on DS.

Research on Tool Wear Form in Micro Turn-Milling Process

2012 ◽  
Vol 184-185 ◽  
pp. 663-667 ◽  
Author(s):  
Lin Hui Zhao ◽  
Jian Cheng Zhang ◽  
Wei Su
Keyword(s):  
Tool Wear ◽  
Small Diameter ◽  
Milling Process ◽  
Milling Tool ◽  
Key Factor ◽  
Part Surface ◽  
End Mills ◽  
Series Of Experiments ◽  
Turn Milling ◽  
Wear Condition

In micro machining, turn-milling tool wear is a key factor for part surface quality. This paper carries on experiments on end mills wear in micro turn-milling machining, aiming to research the wear form and provide some reference data for developing wear standard of small diameter end mills. To measure wear condition of end mills, machine vision technique is utilized. This paper designs and sets up an online end mill wear measurement system for a micro turn-milling process center. With a series of experiments on small diameter end mills, wear conditions of different cutting positions are researched. Based on analysis of experiment data, wear characteristics and wear rule for micro turn-milling process are summarized in this paper.

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