Welding & Joining Processes - Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering welding processes, equipment, safety, joints, defects, testing, and standards drawn from the Welding & Joining Processes lecture notes.

Welding

A process of joining metals by heating and melting to fuse pieces together.

Joining processes

Techniques used to join parts in manufacturing, with welding being a major method.

American Welding Society (AWS)

Organization that standardizes welding processes and classifications.

Oxy-fuel gas welding (OFW)

Welding using a flame produced by burning fuel gas with air or oxygen.

Oxyacetylene welding (OAW)

A type of OFW that uses an acetylene-oxygen flame.

Pressure gas welding (PGW)

Welding by heating metals and applying pressure from gas flames, usually without filler metal.

Arc welding

Joining metals by heat from an electric arc between an electrode and the workpiece.

SMAW (Shielded Metal Arc Welding)

Arc welding using a consumable flux-coated electrode.

GMAW (Gas Metal Arc Welding)

MIG welding; uses a bare wire electrode and shielding gas.

GTAW (Gas Tungsten Arc Welding)

TIG welding; uses a non-consumable tungsten electrode with shielding gas.

FCAW (Flux Cored Arc Welding)

Arc welding with a flux-core wire providing shielding and alloying elements.

SAW (Submerged Arc Welding)

Arc welding with flux covering the arc; high deposition rate and protection from arc visibility.

PAW (Plasma Arc Welding)

Welding that uses a plasma arc for precise, high-energy welding.

Thermit Welding (TW)

Exothermic reaction welding using thermite; no external heat source.

LBW (Laser Beam Welding)

Welding with a focused laser beam for high energy density and precision.

ESW (Electroslag Welding)

Welding of thick sections using flux slag to melt filler metal in a vertical process.

FW (Flash Welding)

Resistance welding where flash is expelled and parts join under pressure.

IW (Induction Welding)

Welding by heating parts through induced currents and magnetic fields.

EBW (Electron Beam Welding)

Vacuum fusion welding using a high-energy electron beam.

Oxyacetylene flame temperature

Approximately 3200°C, a very hot flame used in OFW/OAW.

Welding torch components

Handheld device comprising torch body, gas tubes, control valves, mixer, flame tube, and nozzle.

Gas regulators

Devices that control cylinder pressure and regulate flowing gas to the torch; have high and low gauges.

Flashback arresters

Safety devices that prevent flame from traveling back into hoses/regulators.

Gas color coding

Hoses: acetylene typically red; oxygen typically green.

Hose threading

Acetylene fittings use left-hand threads; oxygen fittings use right-hand threads.

Non-return valve

One-way valve that prevents reverse gas flow in lines.

Beveling

Beveling metal edges to provide a larger welding surface for thick pieces.

Metal preparation

Cleaning metal of dirt, oil, paint, rust; beveling surfaces as needed; brushing after heating.

Butt Joint

A joint where two pieces are in the same plane and joined end-to-end.

Corner Joint

A joint formed at a corner where two pieces meet at an angle.

Tee Joint

A joint where one piece intersects another at a 90° or 45° angle to form a T.

Lap Joint

Two pieces overlapped along their edges for welding.

Edge Joint

Joining along the edge of two plates.

Five Essentials to Obtain Quality Welds

Correct Current, Correct Arc Length, Correct Travel Speed, Correct Size of Electrode, Correct Electrode (selection).

Arc length

Distance from the electrode to the workpiece; typically about equal to the core wire diameter.

Too short arc

Causes sticking and slag entrapment.

Too long arc

Exposes weld to atmosphere, reduces heat concentration, increases spatter.

Travel speed

Speed of welding along the joint; affects fusion, slag coverage, and efficiency.

Electrode size

Diameter of the electrode; larger sizes require more current; choose appropriately.

Flux (coating) functions

Protects molten weld metal, stabilizes the arc, improves weld quality, and can add desirable properties and deposition rate.

PPE (Personal Protective Equipment)

Protective gear for welders including helmet, gloves, jackets, and footwear.

Welding helmet

Protects eyes and face from radiation, sparks, and spatter.

Welding gloves

Leather gloves protecting hands from heat, shock, and radiation; often with gauntlet cuffs.

Protective clothing (ANSI Z49.1)

Flame-resistant attire providing full body coverage; prevents burns from sparks and radiation.

ANSI Z49.1-2012

Standard for welding and cutting protective clothing and equipment.

Steel-toe shoes

Safety footwear required to protect feet in welding environments.

Dye penetrant examination

Non-destructive test using dye and developer to reveal surface cracks.

Hardness testing

Non-destructive test to measure hardness; Brinell 220 BHN is typical for mild/low-alloy steel.

Magnetic Particle Testing

Non-destructive test using magnetic fields and iron particles to reveal surface/subsurface cracks in ferromagnetic materials.

Radiographic examination

Non-destructive test using gamma or X-rays to reveal internal defects in welds.

X-ray examination

Radiographic examination using X-rays to detect internal weld flaws.

Ultrasonic examination

Non-destructive test using high-frequency sound waves to detect flaws by reflection timing.

Common welding defects: Incomplete Penetration

Root pass does not fuse through the full thickness of the joint.

Lack of Fusion

Weld does not fuse with base metal or previous weld pass.

Undercut

Grooving of base metal at weld toe due to excessive heat/ current.

slag inclusions

Slag trapped within the weld metal due to incomplete cleaning or improper welding.

Porosity

Small gas pockets in the weld caused by moisture or contamination.

Burn-through

Excessive heat causes the weld to burn through the base metal.

Underfill

Final weld bead is thinner than the base metal.

Overlap

Filler material extends beyond the edge of the previous weld bead.

Cracks

Fractures in weld or base metal due to stresses or improper pre-heat.

Pinholes

Small holes from escaping gas in the weld, often from moisture.

Inclusion

Foreign material trapped in weld metal, such as slag.

Destructive testing

Tests that deform or fracture the material to assess properties (e.g., tensile, bending, sectioning).

Tensile test

Destructive test measuring ultimate tensile strength and ductility.

Bending test

Destructive test evaluating crack tendency and ductility by bending the specimen.

Sectioning

Destructive test where a weld is cut to inspect the cross-section.

Non-destructive testing (NDT)

Methods to evaluate weld quality without damaging the part (e.g., dye penetrant, radiography, ultrasound).

Heat-affected zone (HAZ)

Area of base metal whose properties have been altered by welding heat.

Oxyacetylene flame envelope types

Neutral flame (balanced O2/acetylene), oxidizing flame (excess O2), carburizing flame (excess acetylene) with characteristic cones and temperatures.

Oxygen and acetylene storage

Oxygen cylinders store at high pressure (up to ~300 bar); acetylene is dissolved in acetone in porous material and stored at lower pressure (~15 bar).