Download GTU BE/B.Tech 2019 Winter 7th Sem New 2172111 Advances In Welding Metallurgy Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER- VII (New) EXAMINATION — WINTER 2019

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Instructions:

1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

MARKS

Q.1 (a) Expand the following terms: 03

1. SMAW,

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2. PTAW and
3. FCAW.

(b) Discuss the effect of heat input and inter pass temperature on 04 mechanical properties of steel.

(c) State the various advances in the welding processes in terms of 07 productivity and quality.

Q.2 (a) What are static and dynamic characteristics of power sources? 03

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(b) Sketch V-I characteristic of CC and CV type welding power 04 source.

(c) Enlist the electronic power regulation systems and explain the 07 salient features available in latest welding equipment.

OR

(c) Compare Thyristor Control —Synergic Pulse Control — Inverter 07 Control Power Sources in terms of features.

Q.3 (a) What are low hydrogen- electrodes and the need for their 03 development?

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(b) Explain Specifications of following Consumables: 04

1. E6013.and
2. ER-70-S6/ER 70-S2.

(c) Write in-detail about the type of shielding gases used in arc 07 welding processes. Give examples of three possible combination of shielding gas mixtures for specific applications.

OR

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Q.3 (a) Differentiate between agglomerated and fused fluxes. 03

(b) Justify or refute the following statement: “Friction stir welding is 04 ideally suited for welding of Aluminum and its alloys”.

(c) With suitable sketches, explain different variants of friction 07 welding.

Q.4 (a) Discuss the effect of various welding parameters on weld bead 03 profile.

(b) Explain for which metals DC electrode positive (reverse polarity) 04 is suitable to use with GTAW Process?

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OR

Q.4 (a) Justify or refute the following statement: “MIG welding requires 03 DC electrode positive (reverse polarity)”.

(b) Explain why in welding of certain materials, preheating and post- 04 heating are essential?

(c) Explain with schematic, pulsed spray transfer and explain merits 07 and de—merits of Pulsed GMAW.

Q.5 (a) Why vacuum is important in producing a good quality weld in 03 EBW?

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(b) Explain the principle behind Laser Beam Welding. Write some 04 applications.

(c) Explain the process of Plasma Keyhole Welding. 07

OR

Q.5 (a) Explain the need for automation in welding. 03

(b) Explain the process of Needle Arc Micro Plasma Welding. 04

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(c) Write a note on the contribution and use of computational tools to 07 simulate welding processes.

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