Workshop Practice Lab LAB 1
Experiment 1
To introduce the fundamentals of welding, study different types of weld joints,
and perform electric arc welding to weld various joints.
Apparatus:
Electric Arc Welding Plant
Figure:
Theory:
Welding is a process of joining two or more metal pieces by applying heat or pressure, with
or without filler material. It is widely used in industries such as construction, automotive,
aerospace, and manufacturing. Welding processes can be classified into different categories,
including fusion welding (arc welding, gas welding) and solid-state welding (friction
welding, ultrasonic welding).
Types of Weld Joints:
1. Butt Joint: Two metal pieces are placed in the same plane and welded along the
joining edge.
2. Lap Joint: One piece overlaps the other, and welding is done along the overlapping
edge.
3. Tee Joint: One metal piece is positioned perpendicular to another, forming a ‘T’
shape, and welding is done along the intersection.
4. Corner Joint: Two pieces are joined at a right angle, forming an ‘L’ shape.
5. Edge Joint: The edges of two metal pieces are placed together and welded along the
length.
Sheet Metal Forming and Welding 1
Techniques Shop
Workshop Practice Lab LAB 1
Procedure:
1. Preparation of Workpieces:
o Clean the metal surfaces using a wire brush or grinder to remove rust, oil, or dirt.
o Align the workpieces as per the selected weld joint type and secure them using
clamps.
2. Setting Up the Welding Machine:
o Connect the electrode holder and ground cable properly.
o Select the correct current setting based on the electrode and material thickness.
3. Striking the Arc:
o Hold the electrode at a slight angle and strike it against the metal surface like
striking a match.
o Once the arc is established, maintain a consistent gap between the electrode and
workpiece.
4. Welding Process:
o Move the electrode steadily along the joint, maintaining a uniform bead.
o Adjust travel speed and electrode angle to avoid defects like porosity and
undercut.
5. Cooling and Cleaning:
o Allow the welded joint to cool naturally.
o Remove slag using a chipping hammer and clean with a wire brush.
6. Inspection of Weld:
o Check for uniformity, penetration, and any visible defects.
o Perform necessary corrections if required.
Precautions:
Always wear proper PPE to protect from heat, sparks, and UV radiation.
Ensure proper ventilation to prevent fume inhalation.
Do not touch hot metal surfaces immediately after welding.
Check electrical connections before starting the welding process.
Keep flammable materials away from the welding area.
Sheet Metal Forming and Welding 2
Techniques Shop
Workshop Practice Lab LAB 1
Comments
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Sheet Metal Forming and Welding 3
Techniques Shop
