دنیای جوشکاری
دنیایی از مطالب جوشکاری و بازرسی فنی
دنیای جوشکاری
دنیایی از مطالب جوشکاری و بازرسی فنیInfluences of diffusion bonding process parameters on bond characteristics of Mg-Cu dissimilar joints
Abstract:
In many circumstances, dissimilar metals have to be bonded together and the resulting joint interfaces must typically sustain mechanical and/or electrical forces without failure, which is not possible by fusion welding processes. The melting points of magnesium (Mg) and copper (Cu) have a significant difference (nearly 400 ..) and this may lead to a large difference in the microstructure and joint performance of Mg-Cu joints. However, diffusion bonding can be used to join these alloys without much difficulty. This work analyses the effect of parameters on diffusion layer thickness, hardness and strength of magnesium-copper dissimilar joints. The experiments were conducted using three-factor, five-level, central composite rotatable design matrix. Empirical relationships were developed to predict diffusion layer thickness, hardness and strength using response surface methodology. It is found that bonding temperature has predominant effect on bond characteristics. Joints fabricated at a bonding temperature of 450 .., bonding pressure of 12 MPa and bonding time of 30 min exhibited maximum shear strength and bonding strength of 66 and 81 MPa, respectively.
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Experimental study of diffusion welding/bonding of titanium to copper
Abstract:
In the present study, Ti–6Al–4V alloy was bonded to electrolytic copper at various temperatures of 875, 890 and 900 C and times of 15, 30 and 60 min through diffusion bonding. 3 MPa uniaxial load was applied during the diffusion bonding. Interface quality of the joints was assessed by microhardness and shear testing. Also, the bonding interfaces were analysed by means of optical microscopy, scanning electron microscopy and energy dispersive spectrometer. The bonding of Ti–6Al–4V to Cu was successfully achieved by diffusion bonding method. The maximum shear strength was found to be 2171 N for the specimen bonded at 890 C for 60 min. The maximum hardness values were obtained from the area next to the interface in titanium side of the joint. The hardness values were found to decrease with increasing distance from the interface in titanium side while it remained constant in copper side. It was seen that the diffusion transition zone near the interface consists of various phases of Cu4Ti, Cu2Ti, Cu3Ti2, Cu4Ti3 and CuTi.
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Gas tungsten arc welding of CP-copper to 304 stainless steel using different filler materials
Abstract:
The dissimilar joining of CP-copper to 304 stainless steel was performed by gas tungsten arc welding process using different filler materials. The results indicated the formation of defect free joint by using copper filler material. But, the presence of some defects like solidification crack and lack of fusion caused decreasing tensile strength of other joints. In the optimum conditions, the tensile strength of the joint was 96% of the weaker material. Also, this joint was bent till to 180º without any macroscopic defects like separation, tearing or fracture. It was concluded that copper is a new and good candidate for gas tungsten arc welding of copper to 304 stainless steel.
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(Heat Input In Full Penetration Welds In Gas Metal Arc Welding (GMAW
Abstract:
Weld bead characteristics are metallurgically controlled by heat input, which depends on the welding parameters. However, for numerous welding specialists, an accurate measurement of the current, voltage, and welding speed is enough for preventing unambiguous process specifications. But a comprehensive knowledge of the effect of others parameters, such as plate thickness and the type of pass to be performed (full penetration, root pass, or filler pass), is also required if a less conservative welding procedure is aimed. The goal of the present paper is to increase the ability to control the quality of the welding processes used in production by considering the effect of heat losses through the back side of the weld by radiation for full penetration welding, when developing welding procedure specifications. It is concluded that the thermal efficiency factor and, consequently, the heat input need to be differentiated in the welding specifications for full penetration welding.
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Narrow Gap Welding Of Heavy Wall Thickness Materials In Nuclear & Fossil Fuel Industries
عنوان مقاله به زبان فارسی: جوشکاری شیار باریک مواد با ضخامت بسیار بالا در صنایع هسته ای و نفت و گاز
TIG welding of heavy wall thickness materials in an orbital configuration, or prefabricated on rotating work pieces is ever more common despite the many alternative technologies. This process has proven that once all the constraints have been taken into account; TIG welding remains the best process for dealing with the many inconsistencies that have to be incorporated to make automation successful.
POLYSOUDE has paid close attention to the various manufacturing conditions which, due to their complexity, require a specific solution almost every time. It brings accommodation of the technical procedure and the welding equipment to reach the most apposite compromise.
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دانلود 10 مقاله با موضوع تاثیر هندسه پین در جوشکاری اصطکاکی اغتشاشی (Influence Of Pin Geometry On FSW)
هندسه پین یکی از پارامترهای مهم و اساسی در جوشکاری اصطکاکی اغتشاشی (Friction Stir Welding) است که تاثیر به سزایی در ساختار منطقه جوش دارد. موضوع مقالاتی که در این پست قرار گرفته نیز به همین مقوله ارتباط دارد. لیست این مقالات را می توانید در ذیل مشاده کنید:
I- Characterization of the influences of FSW tool geometry on welding forces and weld tensile strength using a instrumented tool
II- Effect of Pin tool Shape on Metal Flow During Friction Stir Welding
III- Effect of tool geometry and process condition on static strength of a magnesium friction stir lap linear weld
IV- Effect of tool geometry on microstructure and mechanical properties of friction stir lap welded magnesium alloy and steel
V- Influence of the Tool Pin and Shoulder on Microstructure and Natural Aging Kinetics in a Friction-Stir-Processed 6061–T6 Aluminum Alloy
VI- Influences of pin profile and rotational speed of the tool on the formation of friction stir processing zone in AA2219 aluminium alloy
VII- Influences of tool pin profile and tool shoulder diameter on the formation of friction stir processing zone in AA6061 aluminium alloy
VIII- Influences of tool pin profile and welding speed on the formation of friction stir processing zone in AA2219 aluminium alloy
IX- Selection of FSW tool pin profile, shoulder diameter and material for joining AZ31B magnesium alloy – An experimental approach
X- The influence of pin geometry on bonding and mechanical properties in friction stir weld 2014 Al alloy
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دانلود 10 مقاله با موضوع جوشکاری فلزات غیرهمجنس به روش جوشکاری با پرتو لیزر (Laser Welding Of Dissimilar Metals)
در این قسمت 10 مقاله موضوع جوشکاری فلزات غیرهمجنس به روش جوشکاری با پرتو لیزر (Laser Welding Of Dissimilar Metals) برای شما عزیزان آماده کرده ایم. لازم به ذکر است که تمامی این مقالات به زبان انگلیسی بوده و از مقالات سایت معروف و معتبر Science Direct می باشند. عنوان مقالاتی که در بخش قرار داده ایم به این شرح است:
I- Dissimilar pulsed Nd:YAG laser welding of pure niobium to Ti–6Al–4V
II- Laser beam welding o f dissimilar ferritic/martensitic stainless steels in a butt joint configuration
III- CW/PW dual-beam YAG laser welding of steel/aluminum alloy sheets
IV- Dissimilar welding of carbon steel to 5754 aluminum alloy by Nd:YAG pulsed laser
V- Laser direct joining of carbon fiber reinforced plastic to zinc-coated steel
VI- Dissimilar joining of galvanized high-strength steel to aluminum alloy in a zero-gap lap joint configuration by two-pass laser welding
VII- Laser welding of Ti–6Al–4V to Nitinol
VIII- CO2 laser beam welding of dissimilar magnesium-based alloys
IX- Laser beam welding of dissimilar stainless steels in a fillet joint configuration
X- Laser shock welding of aluminum/aluminum and aluminum/copper plates
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Effect of tool geometry on microstructure and mechanical properties of friction stir lap welded magnesium alloy and steel
ABSTRACT:
The effect of tool geometry on microstructure and mechanical properties of friction stir lap welded AZ31 Mg alloy (top sheet) and steel (zinc coated steel and brushed finish steel) sheets was studied. Tools with two different probe lengths were used in this study. The microstructure at the joining interface, the failure loads and the fracture locations of the joints varied significantly with the probe length. For zinc coated steel joints, the short probe contributed to defect-free joints and high-strength joints; for brushed finish steel joints, long probe improved significantly the failure loads of the joints. The joints welded using a long probe fractured at the stir zone of magnesium alloy side while those welded using short probe fractured at the joining interface.
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Effects of temperature and shielding gas mixture on fatigue life of 5083 aluminum alloy
A fatigue crack develops as a result of stress concentration and extends with each load cycle until failure occurs, or until the cyclic loads are transferred to redundant members. The fatigue performance of a member is more dependent on the localized state of stress than the static strength of the base metal or the weld metal.
This is a study of fatigue strength of Al5083-O aluminum alloy to investigate influence of fatigue life on welding zone according to the mixing shield gas ratio and the test temperature. The GMAW was carried out for weld specimens with various mixing shield gas ratios (Ar100% + He0%, Ar67% + He33%, Ar50% + He50%, and Ar33% + He67%). The test temperatures for the fatigue test were +25 ◦C (+77 ◦C), −30 ◦C (−22 ◦C), −85 ◦C (−121 ◦C), and −196 ◦C (−321 ◦C). The welding zone was divided into four subzones for analysis; weld metal, fusion line, HAZ, and base metal according to the notch position. Regarding the influence on the bead shape of the mixing shield gas ratio, the bead width was greatest in Ar100% + He0% mixture. But the bead depth and area were greatest in Ar33% + He67% mixture. The dilution was also best in the mixing shield gas ratio. In the influence of mixing gas ratio, fatigue life of weld metal specimens decreased with higher argon gas ratio, but fusion line and HAZ specimens were not influenced greatly. Also, the fatigue life increased at lower temperatures, particularly at −196 ◦C.
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Weldability of AZ31B Magnesium Sheet by Laser Welding Processes
Due to finite fossil fuel resources and the impact on our environment of burning fossil fuels, the automotive industry has been investigating ways to reduce the overall weight of automotive vehicles. This has led to increased interest in ways that light weight alloys such as magnesium can be used in fabrication of automotive parts and manufacturing processes such as welding that would enable increased use of magnesium. The objectives of this project were to characterize and determine the weldability of 2 mm thick AZ31B-H24 magnesium alloy by three different laser beam welding processes: a 4 kW Nuvonyx ISL-4000L high power diode laser, a 5 kW Trump TLC-1005 CO2 laser, and a 10 kW YLR-10000-WC fibre laser.
The diode laser operated with a 0.9 by 12 mm spot size and with a maximum power density of 37 MW/m2. Due to its low power density, the diode laser was restricted to conduction-mode welding which produced wide fusion zones. The AZ31B magnesium laser welds exhibited a number of defects including hydrogen porosity, solidification cracking, liquation cracking, high vaporization rates, molten expulsions, and poor weld bead quality due to low surface tension. It was found that the majority of these defects could be controlled through the proper use of clamping and shielding of the weld pool and joint preparation and surface cleaning prior to welding.
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