scholarly journals Laser Surface Structuring of Cemented Carbide for improving the Strength of Induction Brazed Joints

2019 ◽  
Vol 3 (2) ◽  
pp. 44 ◽  
Author(s):  
Ammar Ahsan ◽  
Igor Kryukov ◽  
Stefan Böhm
Keyword(s):  
Joint Strength ◽  
Total Surface Area ◽  
Cemented Carbide ◽  
Surface Pattern ◽  
Micro Patterning ◽  
Brazed Joints ◽  
Diode Pumped ◽  
Surface Patterns ◽  
Steel Joints ◽  
Surface Increase

The effect of micro patterning of cemented carbide surface using nanosecond diode pumped solid-state pulsed laser on the strength of induction brazed carbide and steel joints has been investigated. Surface patterns increase the total surface area of the joint and, for an originally hydrophilic surface, increase the wettability of a liquid on a solid surface such that, instead of building droplets, the liquid spreads and flows on the surface. Microcomputed tomography (µ-CT) was used to observe the filler/carbide interface after brazing and to analyze the presence of porosity or remnant flux in the joint. Microstructures of the brazed joints with various surface patterns were analyzed using scanning electron microscopy. The strength of the joints was measured using shear tests. Results have shown that the groove pattern on the surface of carbide increases the joint strength by 70–80%, whereas, surface patterns of bi-directional grooves (grid) reduced the joint strength drastically. Dimples on the carbide surface did not show any improvement in the strength of the brazed joints compared to samples with no surface pattern.

Effects of Ni and Co Additions to Filler Metals on Ag-Brazed Joints of Cemented Carbide and Martensitic Stainless Steel

2014 ◽  
Vol 922 ◽  
pp. 322-327 ◽  
Author(s):  
Kengo Kaiwa ◽  
Shinji Yaoita ◽  
Tomohiro Sasaki ◽  
Takehiko Watanabe
Keyword(s):  
Stainless Steel ◽  
Joint Strength ◽  
Martensitic Stainless Steel ◽  
Braze Alloy ◽  
Cemented Carbide ◽  
Suppression Effect ◽  
Brazed Joints ◽  
Co Addition ◽  
Multiple Addition ◽  
Filler Metals

This study focuses on understanding the effect of Ni and Co additions to filler metals on Ag-brazed joints of cemented carbide and martensitic stainless steel. Ni and Co added braze alloys were processed based on Ag-Cu-Zn ternary alloy, and joint strength and microstructure of the brazed layer has been investigated. The joint strength increased by the 2.0mass%Ni and 0.5mass%Co addition into braze alloy. This trend is remarkable in the Co added alloy, and the brazed joint increased by 141% compared to that in no-added alloy. The joint strength was closely related to the suppression effect of Co dissolution from cemented carbide into filler layer and Fe diffusion from the stainless steel to the brazed layer. In the brazed microstructure, Co-depleted zone caused by dissolution of Co in the cemented carbide was observed near the interface between the cemented carbide and the steel. Width of the Co-depleted zone significantly decreased in the Co added alloy. However, the joint strength decreased in the multiple addition compared to that in the single addition of Ni or Co.

Microboring of Fine Powder Cemented Carbide Using Diode-pumped Q-switched YAG Laser

2006 ◽  
Vol 40 (93) ◽  
pp. 21-28
Author(s):  
Yasuhiro OKAMOTO ◽  
Norio KATAOKA ◽  
Yoshiyuki UNO ◽  
Eiji YUASA ◽  
Shin-ichiro KUBOTA
Keyword(s):  
Fine Powder ◽  
Cemented Carbide ◽  
Yag Laser ◽  
Diode Pumped

Analysis of Residual Stresses and Distortions in Brazed Joints of Cemented Carbide and Steel

2005 ◽  
Vol 490-491 ◽  
pp. 491-496 ◽  
Author(s):  
A. Ottlik ◽  
Volker Schulze ◽  
L. Pintschovius ◽  
Hermann Müller ◽  
Detlef Löhe
Keyword(s):  
Residual Stresses ◽  
Fatigue Behaviour ◽  
Complex Stress ◽  
Cemented Carbide ◽  
Experimental Characterization ◽  
Fem Simulations ◽  
X Ray ◽  
Brazed Joints ◽  
Stress States

Brazing of cemented carbides to steel bodies gives rise to the development of complex stress states and distortions which influence the fatigue behaviour of the parts. It is quite important to estimate the residual stresses with numerical methods whose agreement is to be guaranteed with experimental characterization of the brazed parts. In this work FEM simulations and X-ray as well as neutron stress analysis were used to examine the residual stresses of brazed samples. Joints with different geometries and dimensions made of cemented carbide and different steels showing different phase transformation behaviours were investigated.

Analysis of Residual Stresses and Distortions in Brazed Joints of Cemented Carbide and Steel

2005 ◽  
pp. 491-496
Author(s):  
A. Ottlik ◽  
Volker Schulze ◽  
L. Pintschovius ◽  
Hermann Müller ◽  
Detlef Löhe
Keyword(s):  
Residual Stresses ◽  
Cemented Carbide ◽  
Brazed Joints

scholarly journals Effects of Interfacial Reactions on Microstructures and Mechanical Properties of 3003 Al/T2 Cu and 1035 Al/T2 Cu Brazed Joints

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 248
Author(s):  
Man Zhang
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Stress Concentration ◽  
Joint Strength ◽  
Interfacial Reactions ◽  
Composition Analysis ◽  
Dispersion Strengthening ◽  
Al Content ◽  
Brazed Joints ◽  
Filler Metals

To meet the demand for efficient and reliable copper and aluminum (Cu/Al) joints in refrigeration and electric power industries, interfacial reactions in 3003 Al/T2 Cu and 1035 Al/T2 Cu joints brazed by Zn-xAl (x ranged from 2–25 wt.%) filler metals and their effects on the mechanical properties of the joints were investigated. Microstructures and fracture surfaces were observed combining with composition analysis. For 3003 Al/Cu joints, bulk CuAl and CuAl2 intermetallic compound (IMC) formed in brazing seams, and a CuAl IMC layer formed at the Cu side interfaces. For 1035 Al/Cu joints, bulk CuAl2 IMC formed in brazing seams, and an Al4.2Cu3.2Zn0.7 IMC layer formed at the Cu side interfaces. For both kinds of joints, shear strength increased first, then decreased with the increasing Al content. The increase in shear strength was because Al promoted the formation of Cu-Al IMC, and caused dispersion strengthening. With the excessive Al content, however, the bulk IMC became coarse and the IMC layers at Cu side interfaces grew thick, causing the joint strength to decrease due to stress concentration. The strength of 3003 Al/Cu joints was always higher than that of 1035 Al/Cu, and their highest strength were achieved by Zn-12Al and Zn-15Al, respectively.

Surface Replication and Structural Development in Micromolding for Micro/Nanocomposites

2007 ◽  
Author(s):  
H. Ito ◽  
K. Kazama ◽  
T. Kikutani
Keyword(s):  
Laser Scanning ◽  
Hexagonal Boron Nitride ◽  
Laser Scanning Microscopy ◽  
Surface Pattern ◽  
Confocal Laser ◽  
Order Structure ◽  
Structural Development ◽  
Molded Parts ◽  
Surface Patterns ◽  
Micro Features

Micromolding with micro-scale surface features of hexagonal boron nitride (h-BN) / polypropylene (PP) composites with different h-BN component was performed to improve molded parts’ heat diffusivity and processability. Effects of h-BN content and process parameters on processability, higher-order structure, and microscale surface patterns of molded parts were analyzed using SEM, WAXD, SPM, and confocal laser scanning microscopy. The replication ratio of the microscale surface pattern and flow length of composite molded parts was improved by compounding the h-BN filler. The replication ratio of the microscale surface pattern near the flow end became greater than 1.0 because of deformation of surface patterns during de-molding. The replication ratio and shape of surface patterns of molded parts were improved with the increase of the h-BN component. The h-BN platelet oriented inside surface micro-features; skin-shear-core structures were well observed in the molded parts.

Surface Patterning of Stainless Steel in Prevention of Fouling in Heat Transfer Equipment

2013 ◽  
Vol 762 ◽  
pp. 493-500 ◽  
Author(s):  
Tiina M. Pääkkönen ◽  
Ulla Ojaniemi ◽  
Markus Riihimäki ◽  
Esa Muurinen ◽  
Carey J. Simonson ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Thermal Conditions ◽  
Surface Patterning ◽  
Surface Pattern ◽  
Stainless Steel Surface ◽  
Cfd Modelling ◽  
Carbonate Solutions ◽  
Wide Range ◽  
Surface Patterns

Fouling of surfaces is a major challenge in design and operation of many industrial heat transfer equipment. Fouling causes significant energy, material and production losses, which increase the environmental impact and decrease economic profitability of processes. Even small improvements in prevention of fouling would lead to significant savings in a wide range of heat transfer applications. In this study, crystallization fouling of aqueous calcium carbonate solutions on a heated stainless steel surface is used to investigate the prevention of fouling in heat transfer equipment by physical surface modifications. Fouling behaviour of different surface patterns are studied experimentally in a laboratory scale fouling test apparatus. CFD modelling is used to study hydrodynamic and thermal conditions near surfaces with different patterns. In addition, the effect of surface pattern on the removal of particles is studied numerically. Surface patterning is found to affect the hydrodynamic and thermal conditions near the wall, and therefore to change the conditions for fouling layer build-up and removal, when compared to a flat heat transfer surface. The most promising surface pattern includes curved shapes, and it seems to create flow conditions in which improved convective heat transfer decreases the driving force for crystallization fouling. In addition, curved surfaces increase the shear forces at the wall, which prevents adhesion of the foulants to the surface and increases resuspension.

Role of Si(100) Surface Patterns in the Phase Separation of Cu/Sn Thin Films

2001 ◽  
Vol 672 ◽  
Author(s):  
Qin Hu ◽  
Martin Zinke–Allmang ◽  
Ian V. Mitchell
Keyword(s):  
Thin Film ◽  
Thermal Decomposition ◽  
Phase Separation ◽  
Ex Situ ◽  
Surface Pattern ◽  
Length Scale ◽  
Thermal Decomposition Process ◽  
Surface Patterns ◽  
Initial Pattern

ABSTRACTWe report on the competitive phase separation of copper and tin thin film deposits on a pre–patterned Si(100) surface. The initial pattern on Si(100) was achieved through a thermal decomposition process of an ex–situ grown oxide film. Copper and tin phase separation on silicon is a competitive process with Cu forming preferrably silicide. Sn is observed to cover the silicide clusters when present in a sufficient amount. The pre–patterning of the surface introduces a new length scale in the problem. Our data suggest that this length scale plays a role while the clustering (ripening) length scale is of the same order, i.e., during nucleation and the early phase separation, but that both length scales become independent once the length scale of ripening significantly exceeds the length scale of the surface pattern.

Friction Behavior for Micro-Scale Grooved Crosshatch Pattern under Lubricated Sliding Contact

2007 ◽  
Vol 345-346 ◽  
pp. 769-772 ◽  
Author(s):  
Young Hun Chae
Keyword(s):  
Friction Coefficient ◽  
Bearing Steel ◽  
Friction Reduction ◽  
Surface Pattern ◽  
Stribeck Curve ◽  
Friction Property ◽  
Friction Behavior ◽  
Groove Surface ◽  
Surface Patterns ◽  
Pin On Disk

Some surface patterns of tribological application are an attractive technology of engineered surface. Because of the friction reduction is considered to be necessary for improved efficiency of machine. This study was investigated for the effect of friction property for angles of micro-crosshatch groove surface pattern on bearing steel used pin-on-disk test. We obtain sample which can be fabricated by photolithography process. We discuss the friction property depended on an angle of crosshatch groove surface pattern. We can verify the lubrication mechanism as Stribeck curve which has a relationship between the friction coefficient and a dimensionless parameter under the lubrication condition. It was found that the friction coefficient was related to angle of crosshatch groove pattern on contact surface.

Microstructure and Strength of Alumina-Metal Joint Brazed by Activated Molybdenum–Manganese Method

2007 ◽  
Vol 353-358 ◽  
pp. 2049-2052 ◽  
Author(s):  
Gui Wu Liu ◽  
Guan Jun Qiao ◽  
Hong Jie Wang ◽  
Zhi Hao Jin
Keyword(s):  
Cooling Rate ◽  
Joint Strength ◽  
Shear Loading ◽  
Holding Time ◽  
Slow Heating ◽  
Heating And Cooling ◽  
Migration Direction ◽  
Process Factors ◽  
Seal Strength ◽  
Steel Joints

High purity alumina/stainless steel joints were produced via activated molybdenummanganese (Mo-Mn) route using 72Ag-28Cu solder. Microstructures of the metallized ceramic and joint sections were observed by scanning electron microscopy. Joint strength was tested by shear-loading method. Some process factors were characterized and analyzed, which include temperature, holding time and heating and cooling rate in ceramic metallization process. The effects of Ni plating and succedent annealing were also investigated. Experimental results show that, migration of glassy phases is the main mechanism of the ceramic metallization. Glass migration direction is from metallizing layer to ceramic side. In the ranges of temperature and holding time of metallization, joint strength firstly increases and then falls with temperature raising and time extending. More fully sintered metallizing layer can be obtained while the temperature increases from 1200oC to 1500oC, and the time prolongs from 30min to 60min. Over-sintering of the metallizing layer will take place with metallizing temperature of 1600 oC and overlong holding time of 70min, which reduces the joint strength. The slower heating and cooling rate, and the annealing after Ni plating both help enhance the seal strength, due to relieving or eliminating interlayer residual thermal stress. However, too slow heating and cooling rate, such as 5 oC /min, is equivalent to overlong holding time and finally also decline the strength. A thin Ni coating helps solder wet metallizing surface, and stops solder erode metallizing layer.

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