20 Questions
What is a characteristic of TW applications?
Weld surface is often smooth enough that no finishing is required
What process is similar to flash welding?
Stud welding
What is a characteristic of flash welding?
Heat generated very rapidly from the arc
What is the purpose of a ceramic ferrule in stud welding?
To both concentrate the heat generated and retain the molten metal in the weld zone
Which of the following is NOT a characteristic of flash welding?
Requires a vacuum chamber
What type of materials can be welded using flash welding?
Similar or dissimilar metals
What is the advantage of using a continuous wire electrode in Gas Metal Arc Welding (GMAW)?
It allows for better use of electrode filler metal.
What is the key difference between self-shielded and gas-shielded Flux-Cored Arc Welding (FCAW)?
The presence or absence of externally supplied shielding gas.
What is an advantage of Gas Metal Arc Welding (GMAW) over Shielded Metal Arc Welding (SMAW)?
It has higher deposition rates.
What is a characteristic of the electrode used in Flux-Cored Arc Welding (FCAW)?
It is a continuous consumable tubing with flux and other ingredients in its core.
What is eliminated in Gas Metal Arc Welding (GMAW) due to the use of shielding gases and a continuous wire electrode?
The need for manual grinding and cleaning of slag.
What is the purpose of the flux in the core of a Flux-Cored Arc Welding (FCAW) electrode?
To produce shielding gases.
What type of electrode is used in Electrogas Welding (EGW)?
Continuous consumable electrode
What is the purpose of molding shoes in Electrogas Welding (EGW)?
To contain molten metal
What type of shielding is used in Submerged Arc Welding (SAW)?
Granular flux
What type of metals are not suitable for Submerged Arc Welding (SAW)?
Nonferrous metals
What is the name of the welding process that uses a nonconsumable tungsten electrode and an inert gas for arc shielding?
Gas Tungsten Arc Welding (GTAW)
What is the melting point of tungsten in degrees Celsius?
3410°C
What type of electrode is used in Gas Tungsten Arc Welding (GTAW)?
Nonconsumable electrode
Which of the following is NOT a type of nonconsumable electrode process?
Submerged Arc Welding (SAW)
Study Notes
Gas Metal Arc Welding (GMAW)
- Uses a continuous wire electrode and shielding gases to eliminate slag on the weld bead
- Advantages over Shielded Metal Arc Welding (SMAW):
- Better arc time due to continuous wire electrode
- Better use of electrode filler metal
- Higher deposition rates
- Eliminates the problem of slag removal
- Can be readily automated
Flux-Cored Arc Welding (FCAW)
- Adaptation of SMAW to overcome limitations of stick electrodes
- Electrode is a continuous consumable tubing containing flux and other ingredients
- Two versions:
- Self-shielded FCAW: core includes compounds that produce shielding gases
- Gas-shielded FCAW: uses externally applied shielding gases
Flash Welding (FW)
- Also known as flash butt welding
- Heat generated rapidly from the arc as the ends of the two specimens begin to make contact
- Ends soften, and molten metal is expelled in the form of sparks
- Suitable for end-to-end or edge-to-edge strips, sheets, rings of similar or dissimilar metals
Stud Welding
- Similar to flash welding
- Also known as stud arc welding
- The stud acts as an electrode and is joined to another flat plate
- A ceramic ferrule is used to prevent oxidation, concentrate heat, and retain molten metal in the weld zone
Electrogas Welding (EGW)
- Uses a continuous consumable electrode, either flux-cored wire or bare wire with externally supplied shielding gases
- Molding shoes are used to contain molten metal
- Can be a special case of self-shielded FCAW or GMAW depending on the electrode used
Submerged Arc Welding (SAW)
- Uses a continuous, consumable bare wire electrode with arc shielding provided by a cover of granular flux
- Electrode wire is fed automatically from a coil
- Flux is introduced into the joint slightly ahead of the arc by gravity from a hopper
- Completely submerges operation, preventing sparks, spatter, and radiation
SAW Applications and Products
- Steel fabrication of structural shapes (e.g., I-beams)
- Seams for large diameter pipes, tanks, and pressure vessels
- Welded components for heavy machinery
- Most steels (except hi C steel)
- Not suitable for nonferrous metals due to reactivity with oxygen and fluxes
Nonconsumable Electrode Processes
- Gas Tungsten Arc Welding (GTAW)
- Plasma Arc Welding
- Carbon Arc Welding
- Stud Welding
Gas Tungsten Arc Welding (GTAW)
- Uses a nonconsumable tungsten electrode and an inert gas for arc shielding
- Tungsten melting point: 3410°C (6170°F)
This quiz covers the advantages of Gas Metal Arc Welding (GMAW) over Shielded Metal Arc Welding (SMAW), including its benefits, process, and applications.
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