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. 

 

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.

  

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.

  

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.

  

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.

 

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.

  

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.

  

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.

  

استحکام جوش و چقرمگی در جوشکاری اینکونل 625 و فولاد ضد زنگ سوپر دوپلکس

Characterization of weld strength and toughness in

 the multi-pass welding of Inconel 625 and

 Super-duplex stainless steel UNS S32750

مشخصه‌یابی استحکام جوش و چقرمگی در جوشکاری چند پاس

اینکونل 625 و فولاد ضد زنگ سوپر دوپلکس UNS S32750

ABSTRACT

The present study investigated the weldability of dissimilar metals involving Inconel 625 and Super-duplex stainless steel obtained from continuous current (CC) and pulsed current (PC) gas tungsten arc welding (GTAW) processes employing ER2553 and ERNiCrMo-4 fillers. A comparative analysis on these dissimilar weldments was carried out to establish the structure-property relationships. Microstructure examination was carried out using optical microscopy (OM) and scanning electron microscopy (SEM) techniques. Grain coarsening was observed at the HAZ of UNS S32750 for all the cases. Mechanical tests ascertained that the PCGTA weldments employing ERNiCrMo-4 offered better weld strength and impact toughness. Elaborative studies on the structure – property relationships of these dissimilar weldments were discussed.

 

جوشکاری اینکونل 625 و فولاد زنگ‎نزن L 304 با پرتوی الکترونی

Microstructure and hardness studies of electron beam

welded Inconel 625 and stainless steel 304L

مطالعه ریزساختار و سختی اینکونل 625 و فولاد زنگ‎نزن L 304

جوشکاری شده با پرتوی الکترون

ABSTRACT

In this study, electron beam welding of dissimilar Inconel 625 and SS 304L alloys was successfully performed by employing optimized electron beam welding parameters. The welded joint was characterized using SEM/EDS, XRD and micro-hardness tester. The welded joint was found homogeneous, well bonded and defect free. Two types of microstructure i.e. columnar dendritic and cellular dendritic were observed in the fusion zone. The development of different microstructures in the fusion zone was attributed to the localized cooling effects during solidification. Few micro-cracks along with dendrites splitting were observed in the vicinity of end crater that was mainly due to the segregation of S element. A significant variation of Ni and Fe was observed across Inconel/FZ and FZ/SS interfaces due to their fast diffusion in the melt pool. Micro-hardness measurements across Inconel/FZ and FZ/SS interfaces showed an increasing trend in the FZ from SS 304L towards Inconel base alloy.