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متغيرات اللحام المثلى بالقوس الكهربائي المغمور باستخدام طريقة تاكوشي == Optimizing of Submerged Arc Welding Parameters Using Taguchi Method
Author name:
هشام جواد كاظم
Supervisor name:
احمد علي اكبر اكبر
General topic:
Production engineering metallurgy and materials
Specific topic:
Metals Engineering
Degree:
Master
University:
University of Technology
Language:
English
University location:
Baghdad
First pages:
50T176 - p.pdf
Abstract:
اللحام بالقوس الكهربائي المغمور غالبا مايستخدم في الصناعات الثقيلة. يستخدم في هذا النوع من اللحام سلك لحام مستمر يكون معدنن الملئ. االقوس يكون مغمور في مساعد الصهر والذي يتم تغذيته من خلال انبوب في حاوية اعلى سلك اللحام الذي يغذى باستمرار. مساعد الصهر يع | Submerged arc welding (SAW) is often used for heavy industries. The SAW process employs a continuous bare wire electrode that is consumed to produce filler, the arc is submerged in the flux, and the flux is supplied through a funnel located ahead of the filler wire which is fed continuously from a hopper, the flux contributes to deoxidize the base metal, and protect the molten weld metal from atmospheric contaminants In order to achieve best weld quality and good mechanical properties in manufacturing industries which need to be optimized. Selection of appropriate SAW parameters is essential to ensure a predictable weld bead which is important for obtaining high quality welding.Manufacturing industries and training centers often face the problem of selecting appropriate or optimum combinations of input welding parameters for achieving the required weld quality. Three input parameters of SAW were used to weld the steel plates, and four levels for each parameter, and three output response variables were used The experimental work consists of welding of sixteen low carbon steel plates of (AISI 1005) specimen measured 300 mm × 50 mm × 12 mm were submerged arc welded using welding currents (280, 340, 400, 460) amp, voltage (26, 29, 32, 35) volt and welding speeds (3.3, 5, 6.6, 8.3) mm/s This work details the application of Taguchi design to determine the optimal SAW parameters. An effort has been made to study the effect of SAW process parameters (current I, voltage V, speed S) on the bead geometry dimensions (depth of penetration P, bead width W, heat affected zone width w).Signal to noise ratios are computed to determine the optimum parameters. Statistical models have been developed based on multiply regression analysis relating the bead geometry with process parameters. The adequacy and significance of the models were checked by using ANOVA technique, also the models are validated using normal probability plot, and residual versus fit plots.The models were employed easily in form of executed program designed by using Visual Basic 6 software. The objective of such models and designed program is to predict weld bead geometry which enables selecting the desired weld parameters and select the weld bead dimensions. The effect of SAW parameters on heat affected zone and weld metal hardness also has been studied by means of hardness measurements, and grain size measurement using intercept method. Main and interaction effects of the process parameters on bead geometry are presented graphically. The experimental results were analyzed by using Minitab 16 software.It was found that current (280 to 460) amp causes increase in depth of penetration from (1.742 to 3.752) mm and HAZ width (1.222 to 1.512) mm. Bead width increases from (10.99 to 13.13) mm with increase in voltage from (26 to 35) volt and decreases from (12.61 - 11.80) mm with increase in welding speed from (3.3 to 8.3) mm/s. The welding speed and voltage do not affect appreciably the depth of penetration. Also change in weld speed reduces the width of the HAZ from (1.462 to 1.295) mm. The hardness of HAZ reaches maximum value 122.39 HV at the center of HAZ and decreases gradually toward the BM 109.22 HV; also it was found that the executed program is a useful tool used to predict weld bead geometry dimensions from welding parameters for SAW process.
