اثر سرعت جوشکاری بر تنش پسماند در طول جوشکاری قوس با الکترود تنگستن تحت پوشش گاز

Influence of welding speed and power on residual stress during gas tungsten arc welding (GTAW) of thin sections

with constant heat input: A study using numerical simulation and experimental validation

اثر سرعت جوشکاری و توان بر تنش پسماند

در طول جوشکاری قوسی الکترود تنگستن (GTAW) مقاطع نازک با ورودی گرمای ثابت

مطالعه ای با استفاده از شبیه سازی و اعتبارسنجی تجربی

ABSTRACT

The temperature distribution and residual stresses for a GTAW circumferential butt joint of AISI 304 stainless steel using numerical simulation have been evaluated. For evaluation of weld induced residual stresses, the analysis of heat source fitting was carried out with heat inputs ranging from 200 to 500 J/mm to arrive at optimal heat input for obtaining proper weld penetration and heat affected zone (HAZ). For this chosen heat input, the influence of different weld speeds and powers on the temperature distribution and the residual stresses is studied. The heat source analysis revealed the best choice of heat input as 300 J/mm. The residual stresses on the inner and outer surfaces, and along the radial direction were computed. Increase in temperature distribution as well as longitudinal and circumferential residual stresses was observed with the increase in weld speed and power. The validity of the results obtained from numerical simulation is demonstrated with full scale shop floor welding experiments.

   

جوشکاری GTAW آلیاژ آلومینیوم تیتانیوم

Effect of Vibration during GTAW Welding on Microstructure and Mechanical Properties of Ti6Al4V

تاثیر ارتعاش در طی جوشکاری GTAW روی ریزساختار و خواص مکانیکی Ti6Al4V 

ABSTRACT

The drive to improve weld quality and process parameters demands the use of improved welding tech niques and materials [1]. Titanium and its alloys are considered to be the best engineering metals for indus trial applications because of their excellent strengthto weight ratio, high fatigue life, toughness, resistance to corrosion and good fatigue strength [2, 3].

Welding methods such as gas tungsten arc, resis tance, and diffusion welding have been developed in response to the expansion of the titanium industry. 

Titanium alloys easily absorb harmful gases because of their high chemical activity, resulting in poor mechanical properties and unstable structure [4, 5]. Gas tungsten arc welding is the preferred method for avoiding these deficiencies [6]. The weld ing of titanium alloys often increases grain size in the welded metal and heat affected zones [7]. Fusion zones typically exhibit coarse columnar grains in response to prevailing thermal conditions during welded metal solidification [6]. These columnar grains produce inferior mechanical properties in the welds [1]. Methods of weld grain refinement include inocu with heterogeneous nucleants, surface nucleation induced by gas impingement, introduction of physical disturbance through techniques such as elec tromagnetic stirring [4]. Vibratory techniques, and pulsed current welding techniques [8].

 

مقایسه جوشکاری EBW و اتصال خود فشاری حرارتی برای آلیاژ Ti6Al4V

A comparative study on electron beam welding and

rigid restraint thermal self-compressing bonding for Ti6Al4V alloy

بررسی مقایسه ای جوشکاری پرتوی الکترونی

و اتصال خود فشاری حرارتی سخت مقیدشده برای آلیاژ Ti6Al4V

ABSTRACT

This study focuses on the influence of joining method difference on the joint microstructure and properties. Unlike vacuum electron beam welding (EBW) utilizing electron beam as fusion heat source, rigid restraint thermal self-compressing bonding (TSCB), a new solid-state bonding method proposed by authors, employs vacuum electron beam as the non-melt heat source to bond materials in this work. Meanwhile, a comparative study on the microstructure and mechanical properties of EBWjoint and rigid restraint TSCB joint was conducted to investigate the effect of this difference on joint microstructure and properties. Results show that compared with EBW joints, the rigid restraint TSCB joints as solid-state joints are homogeneous in terms of microstructure and microhardness profile. Strength of both joints are comparable with that of base metal, but the elongation of the rigid restraint TSCB joint is more close to that of base metal. Rigid restraint TSCB joint has better combination of strength and ductility.

 

اتصال آلیاژهای آلومینیوم 5083 و 6061 به روش جوشکاری اصطکاکی

Joining of 5083 and 6061 aluminum alloys by friction stir welding

اتصال آلیاژهای آلومینیوم 5083 و 6061 به روش جوشکاری اصطکاکی تلاطمی

ABSTRACT

Friction stir welding (FSW) has emerged as a new solid state joining technique [1], especially for aluminum alloys [2–6]. In this process, a rotating tool travels down the length of contacting metal plates, and produces a highly plastically deformed zone through the associated stirring action. The localized heating zone is produced by friction between the tool shoulder and the plate top surface, as well as plastic deformation of the material in contact with the tool [1].

At the present time, FSW is used mainly for joining similar materials. For dissimilar welding, there have been few systematic studies aimed at clarifying the effect of material combination and welding conditions on weld properties [7, 8].