(SEM V) THEORY EXAMINATION 2023-24 ADVANCE WELDING

Course: B.Tech (Mechanical Engineering)

Semester: V

Subject Code: KME055

Subject: Advanced Welding

Maximum Marks: 100

Time: 3 Hours

Pattern: Section A (Short), Section B (Medium), Section C (Long)

SECTION A — Short Answer Questions (2 × 10 = 20 Marks)
 

Students must answer all questions briefly.

Topics include:

Arc Blow – its meaning and causes.                     Solid-State Welding – definition and characteristics.

Working Principle of Friction Welding.            Soldering – process and applications.

Heat-Affected Zone (HAZ) – definition and significance.

                                                                             Cooling Rate – effect on weld microstructure.

Formula for Carbon Equivalent (CE) and its importance in predicting weldability.

                                                                             Reclamation Welding – use and benefits.

Weld Distortion – causes and control methods.

                                                                            Residual Stresses in Welding – effects and methods of reduction.

These questions test the fundamental concepts of welding processes, metallurgy, and weld defects

SECTION B — Descriptive / Medium Questions (10 × 3 = 30 Marks)

Attempt any three questions.
Topics covered:

Arc Length Calculation Problem:

Given: V = (20 + 40L), power source V = (80 – 0.08I).

Task: Determine optimum arc length and corresponding arc power.

(Tests understanding of power-source characteristics and arc stability).

Underwater Welding and Ultrasonic Welding — construction, working, advantages.

Welding Distortion and Factors Affecting HAZ Properties — metallurgical changes and mechanical impact.

Hardfacing — detailed explanation with neat sketch, advantages, limitations, and applications.

Types of Welds and Weld Joints — such as butt, fillet, corner, edge, and tee joints

SECTION C — Long / Problem-Solving Questions (10 × 5 = 50 Marks)
 

Attempt one part from each question (Q3–Q7).
 

Q3. Welding Fundamentals
 

a. Compare welding with other fabrication processes and classify various welding processes.

b. Explain metal transfer types in arc welding with neat sketches (globular, spray, short-circuiting, etc.).
 

Q4. Arc Welding Processes
 

a. Shielded Metal Arc Welding (SMAW): working, advantages, limitations, and flux functions.

b. Laser Beam Welding (LBW) and Gas Tungsten Arc Welding (GTAW): working principles and applications.
 

Q5. Welding Metallurgy
 

a. Numerical Problem:
 

For steel plate (10 mm thick), welded at 20 V, 200 A, 5 mm/sec speed.

Calculate peak temperature at 1.5 mm from fusion boundary given efficiency (f₁ = 0.9), ρc = 0.0044 J/mm³°C, Tm = 1510°C, and room temperature 25°C.

b. Gas-Metal and Slag-Metal Reactions — detailed explanation of chemical interactions in weld pools

Q6. Weldability and Materials

a. Welding of Aluminium Alloys and Cast Iron — challenges and techniques.
b. Effect of Alloying Elements on Weldability and concept of Cladding (overlaying to improve surface properties).

Q7. Weld Defects and Testing

a. Explain Weld Defects (porosity, cracks, slag inclusion, undercut, lack of fusion) with neat sketches, causes, and remedies.
b. Welding Procedure Specification (WPS) and difference between Destructive and Non-Destructive Testing (NDT) methods

 Key Concepts Covered

Welding principles and classification                            Arc characteristics and metal transfer

Heat-affected zone and cooling rate effects                Welding metallurgy and residual stresses

Modern welding techniques (Laser, Ultrasonic, Underwater)  Weld testing and quality control

For Related Learning
 

To explore modern welding methods, industry tools, and engineering guides, visit Tytil.com — it provides helpful insights into manufacturing, joining processes, and materials engineering.

 FAQs
 

Q1. What is the purpose of flux in arc welding?
Flux protects the molten metal from atmospheric contamination and stabilizes the arc.
 

Q2. What is the main difference between welding and soldering?
Welding involves fusion of base metals; soldering joins metals using a filler below melting point.
 

Q3. What are common weld defects?
Cracks, porosity, undercut, slag inclusion, and lack of fusion.
 

Q4. What is carbon equivalent (CE)?
CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 — helps predict steel weldability.
 

Q5. What is hardfacing used for?
Hardfacing improves wear resistance of components by depositing hard materials on surfaces.