دنیای جوشکاری

دنیای جوشکاری

دنیایی از مطالب جوشکاری و بازرسی فنی
دنیای جوشکاری

دنیای جوشکاری

دنیایی از مطالب جوشکاری و بازرسی فنی

اتصال سرامیک Si3N4 با استفاده از آلیاژ پرکننده لحیم

Joining of Si3N4 Ceramic Using PdCo(NiSiB)-V System

Brazing Filler Alloy and Interfacial Reactions

اتصال سرامیک Si3N4 با استفاده از آلیاژ پرکننده لحیم

در سیستم PdCo(NiSiB)-V و واکنش های مرزی

ABSTRACT

The wettability of V-active PdCo-based alloys on Si3N4 ceramic was studied with the sessile drop method. And the alloy of Pd50.0–Co33.7–Ni4.0–Si2.0–B0.7–V9.6 (wt%), was developed for Si3N4 ceramic joining in the present investigation. The rapidly-solidified brazing foils were fabricated by the alloy Pd50.0–Co33.7–Ni4.0–Si2.0–B0.7–V9.6. The average room-temperature three-point bend strength of the Si3N4/Si3N4 joints brazed at 1453 K for 10 min was 205.6 MPa, and the newly developed braze gives joint strengths of 210.9 MPa, 206.6 MPa and 80.2 MPa at high temperatures of 973 K, 1073 K and 1173 K respectively. The interfacial reaction products in the Si3N4/Si3N4 joint brazed at 1453 K for 10 min were identified to be VN and Pd2Si by XRD analysis. Based on the XEDS analysis result, the residual brazing alloy existing at the central part of the joint was verified as Co-rich phases, in which the concentration of element Pd was high up to 18.0–19.1 at%. The mechanism of the interfacial reactions was discussed. Pd should be a good choice as useful alloying element in newer high-temperature braze candidates for the joining of Si-based ceramics.

  ادامه مطلب ...

جوشکاری اصطکاکی-تلاطمی آلیاژ آلومینیوم به فولاد زنگ‌نزن

Friction stir welding of dissimilar Al 6013-T4 To

X5CrNi18-10 stainless steel

جوشکاری اصطکاکی-تلاطمی غیرهمجنس Al 6013-T4 به فولاد زنگ‌نزن X5CrNi  

ABSTRACT

The joining of dissimilar Al 6013-T4 alloy and X5CrNi18-10 stainless steel was carried out using friction stir welding (FSR) technique. The microstructure, hardness and fatigue properties of fiction stir welded 6013 aluminium alloy to stainless steel have been investigated. Optical microscopy was used to characterise the microstructures of the weld nugget, the heat affected zone (HAZ), thermo-mechanical affected zone (TMAZ) and the base materials. The results show that FSR can be used the joining of dissimilar Al 6013 alloy and X5CrNi18-10 stainless steel. Seven different zones of the microstructure in the welding are reported as follows: (1) parent stainless steel, (2) HAZ in the stainless steel at advancing side of weld, (3) TMAZ in the stainless steel at advancing side of weld, (4) weld nugget, (5) TMAZ in the Al alloy at retreating side of weld, (6) HAZ in the Al alloy at retreating side of weld and (7) parent Al alloy. A good correlation between the hardness distribution and the welding zones are observed. Fatigue properties of Al 6013-T4/X5CrNi18-10 stainless steel joints were found to be approximately 30% lower than that of the Al 6013-T6 alloy base metal.

   ادامه مطلب ...

فرآیند شکل دهی ادغام شده با لحیم کاری القایی Induction Brazing

Forming Process Integrated Induction Brazing 

فرآیند شکل دهی ادغام شده با لحیم کاری القایی

ABSTRACT

Processing steps additional to forming operations, such as joining, usually require a vast effort for transport and storage. Due to integration of currently external production steps, processes could be synchronized. Brazing represents an additional operation, which is likely to gain of importance in the light of an increasing relevance of light weight construction. Servo presses enable an adjustment of the ram motion to process requirements. Hence, the ram motion can be adjusted to create a time slot for the execution of additional processes inside the press. In this paper, the possibility to integrate brazing into forming process chains is investigated.  For a demonstration part, a tool that allows brazing inside a servo press is developed. Achievable part qualities and cycle times are  evaluated. 


 

ادامه مطلب ...

لحیم کاری قطره ای لیزری برای اتصال الکتریکی مواد کامپوزیتی

Laser droplet brazing for electrical contacting of composite

materials with integrated active elements

لحیم کاری قطره ای لیزری برای اتصال الکتریکی مواد کامپوزیتی ادغام شده با عناصر فعال

ABSTRACT

To be used as actuators or sensors, piezoceramic components have to be electronically contacted. A temperature stable connection can be achieved with brazing techniques. Since piezoceramics are susceptible to damage by high temperatures and temperature gradients, it is important to control the energy input in the brazing process. Therefore, we use a laser  droplet brazing method which allows for precise contacting of piezoceramics and avoids thermal damage. The influence  of the laser parameters on the brazing process and the contacting accuracy is presented in this paper.


  

ادامه مطلب ...

رفتار خستگی خوردگی آلیاژ آلومینیوم جوشکاری شده

Corrosion fatigue behaviour of aluminium alloy 6061-T651 welded

using fully automatic GMAW and ER5183 filler alloy

رفتار خستگی خوردگی آلیاژ آلومینیوم 6061-T651 جوش داده شده با (GMAW)

با آلیاژ ER5183 به عنوان فیلر

ABSTRACT

The fatigue life of aluminium 6061-T651 at various applied stress amplitudes in the unwelded and welded condition was found to be significantly reduced on immersion in a 3.5% NaCl simulated sea water solution, compared to that measured in ambient air. The ratio of fatigue life in NaCl test solution to that in air increased as the stress amplitude decreased. The observed reduction in the fatigue life in the NaCl test solution was most likely due to the presence of pits which nucleated on second phase particles or precipitates. Welded joints performed using pulsed gas metal arc welding and ER5183 filler wire failed at the interface between the weld metal and the heat-affected zone as a result of a high pitting rate in this region.


  

ادامه مطلب ...

رفتار خستگی خوردگی آلیاژ آلومینیوم جوشکاری شده

Corrosion fatigue behaviour of aluminium alloy 6061-T651 welded

using fully automatic GMAW and ER5183 filler alloy

رفتار خستگی خوردگی آلیاژ آلومینیوم 6061-T651 جوش داده شده با (GMAW)

با آلیاژ ER5183 به عنوان فیلر

ABSTRACT

The fatigue life of aluminium 6061-T651 at various applied stress amplitudes in the unwelded and welded condition was found to be significantly reduced on immersion in a 3.5% NaCl simulated sea water solution, compared to that measured in ambient air. The ratio of fatigue life in NaCl test solution to that in air increased as the stress amplitude decreased. The observed reduction in the fatigue life in the NaCl test solution was most likely due to the presence of pits which nucleated on second phase particles or precipitates. Welded joints performed using pulsed gas metal arc welding and ER5183 filler wire failed at the interface between the weld metal and the heat-affected zone as a result of a high pitting rate in this region.


  

ادامه مطلب ...

شکست خستگی در اتصال جوش داده شده آلیاژ آلومینیوم

Features of AcousticEmission Signals during the Initiation 

of a Fatigue Failure in a Welded Joint of an Aluminum Alloy

of the Al–Cu–Mn System

ویژگی های سیگنال انتشار آکوستیک در طول شروع یک شکست خستگی

در یک اتصال جوش داده شده آلیاژ آلومینیوم سیستم Al-Cu-Mn

ABSTRACT

The features of the generation of acoustic emissions (AEs) during the initiation of a fatigue failure in various zones of a welded joint of thermally hardened 2219T6grade aluminum alloy, which is produced using electronbeam welding, are  considered. Metallographic studies showed that a welded joint of the alloy is structurally and mechanically inhomogeneous. This predominantly influ ences the initiation and development kinetics of fatigue cracks in the joint and the AE kinetics. It is shown that the area of a formed flaw is proportional to the sum of the amplitude of detected signals, and the transition from the initiation to the stable propagation of a failure is accompanied by an abrupt increase in AE activity.


 

ادامه مطلب ...

جوشکاری فولاد زنگ نزن 316 به روش تیگ TIG-welded 316 stainless steel

Acoustic emisson and ultrasonic wave characteristics

in TIG-welded 316 stainless steel

مشخصات انتشار آکوستیک و امواج مافوق صوت در

فولاد ضد زنگ 316 جوش داده شده به روش TIG

ABSTRACT

A TIG welded 316 stainless steel materials will have a large impact on the design and the maintenance of invessel components including pipes used in a nuclear power plant, and it is important to clear the dynamic behavior in the weld part of stainless steel. Therefore, nondestructive techniques of acoustic emission (AE) and ultrasonic wave were applied to investigate the damage behavior of welded stainless steel. The velocity and attenuation ratio of the ultrasonic wave at each zone were measured, and a 10 MHz sensor was used. We investigated the relationship between dynamic behavior and AE parameters analysis and derived the optimum parameters to evaluate the damage degree of the specimen. By measuring the velocity and the attenuation of an ultrasonic wave propagating each zone of the welded stainless steel, the relation of the ultrasonic wave and metal structure at the base metal, heat affected zone (HAZ) metal and weld metal is also discussed. The generating tendency of cumulated counts is similar to that of the load curve. The attenuation ratios from the ultrasonic test results were 0.2 dB/mm at the base zone, and 0.52 dB/mm and 0.61 dB/mm at the HAZ zone and weld zone, respectively.


  

ادامه مطلب ...

جوشکاری تیگ آلومینیوم و منیزیم

اتصال آلومینیوم و منیزیم از طریق جوشکاریA-TIG

 با پیش نورد کمکی همراه با لایه میانی روی 

ABSTRACT

AZ31B Mg and 6061 Al alloys were successfully welded via a novel pre-roll-assisted A-TIG welding technique with Zn interlayer at an overlap configuration. The rolling operation increased the contact area and control tightly between Zn interlayer and plates at an interlayer-assisted overlap configuration to avoid the adverse effect of gaps. B2O3 activating flux was coated on the upper Al plates to provide contraction of the arc column to increase the arc energy density; welding penetration was increased without improving heat input, which reduced the formation and grain coarsening of Al–Mg IMCs. Therefore, the tensile–shear strength of the joints was improved obviously. The average of tensile–shear strength joined was 71.2 MPa with a maximum of 74 MPa compared to 41.1 MPa with a maximum of 45.2 MPa by conventional TIG with Zn interlayer.


  

ادامه مطلب ...

مکانیزم نفوذ فلاکس در جوشکاری تیگ برای آلیاژ آلومینیوم

Study of mechanism of activating flux increasing

weld penetration of AC A-TIG welding for aluminum alloy

مطالعه مکانیزم افزایش مکانیزم نفوذ فلاکس فعال ساز جوشکاری AC  A-TIG

برای آلیاژ آلومینیوم

ABSTRACT

When multi-component flux AF305 is used as surface activating flux for an aluminum alloy, the weld penetration of activating flux-tungsten inert-gas (A-TIG) welding is over two times more than that of conventional TIG welding. Using A-TIG welding with the modes of alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), respectively, the flux differently affects weld penetration when the polarity is different. After studied the effect of compelled arc constriction on weld penetration of AC welding, it is believed that the constriction of the whole arc root is not the main mechanism that flux AF305 dramatically improves weld penetration. The penetration has a relationship with the separate distribution of slag on the weld surface. Then, an observation of scanning electron microscopy (SEM) and an electronic data systems (EDS) analysis of slag were performed respectively. The separate distribution of slag on the weld pool during welding and the great constriction of arc spots were confirmed by TIG welding with helium shielding gas. The relationship between slag distribution and weld penetration was studied by adding aluminum powder into flux AF305 to change the distribution of slag. During welding, the separate distribution of slag on the weld pool results in the great constriction of arc spots, an increase in arc spot force, and an increase in Lorentz force within the arc and weld pool. Finally, the weld penetration is increased.


  

ادامه مطلب ...