Classification of Welding MCQ Quiz in मल्याळम - Objective Question with Answer for Classification of Welding - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

Explanation:

Flux:

• Flux coating acts as deoxidizers; by forming the slag it will protect the liquid metal from atmospheric gases.
• Slag formation controls the heat transfer rate of liquid metal to the weld pool.

Types of welding, working, and use of flux:

Additional Information

Concept:

Power in welding is given as

P = VI

where V = voltage (V), I = current (A)

Calculation:

Given:

Voltage = 20 V, Current = 300 Amp

P = VI

P = 20 × 300 = 6 kW

Explanation:

TIG Welding: 

• Tungsten Inert Gas (TIG) or Gas Tungsten Arc (GTA) welding is the arc welding process in which an arc is generated between a non-consumable tungsten electrode and workpiece.
• The tungsten electrode and the weld pool are shielded by an inert gas normally argon and helium.
• The principle of the tungsten inert gas welding process is shown below.

• In shielded arc welding, heat is generated through an electric arc, causing the metal to melt and fuse.
• Electric-resistance welding involves pressure and heat generated by electrical resistance to join materials, somewhat similar to the principles of forge welding.
• Gas welding uses a flame to melt the metal parts to be joined, which makes it a fusion welding process.
• Thermit welding relies on the chemical reaction between iron oxide and aluminum to produce molten metal, which fuses the components together.

Explanation:

Welding:

• Welding is a metal joining process in which two or more parts are joined or coalesced at their contacting surfaces by suitable application of heat or/and pressure.

Welding processes can be broadly classified into

• Fusion welding
• Pressure welding/solid-state welding/Forge welding
   

Fusion Welding:

• In fusion-welding processes, heat is applied to melt the base metals.
• In many fusion welding processes, a filler metal is added to the molten pool during welding to facilitate the process and provide strength to the welded joint.
• Types: Arc welding, Gas welding, Oxyfuel gas welding, electron beam welding, laser welding, Thermit welding, Electric-resistance welding.
   

Solid-state welding:

• In solid-state welding, the joining of materials is performed with the help of heat and pressure or pressure alone.
• Types: Forge welding, Ultrasonic welding, Explosive welding, Friction welding.
  

Explanation:

Welding:

• Welding is a metal joining process in which two or more parts are joined or coalesced at their contacting surfaces by suitable application of heat or/and pressure.

Welding processes can be broadly classified into

• Pressure welding/solid-state welding
• Fusion welding

Solid-state welding:

• In solid-state welding, the joining of materials is performed with the help of heat and pressure or pressure alone.
• Types: Forge welding, Ultrasonic welding, Explosive welding, Friction welding.

Fusion Welding:

• In fusion-welding processes, heat is applied to melt the base metals.
• In many fusion welding processes, a filler metal is added to the molten pool during welding to facilitate the process and provide strength to the welded joint.
• Types: Arc welding, Gas welding, Oxyfuel gas welding, electron beam welding, laser welding.

Concept:

Projection welding is a multi-spot-welding process.

Introduction to spot welding process:

• In resistance spot welding, two or more sheets of metal are held between electrodes through which welding current is supplied for a definite time and also force is exerted on work-pieces.

Introduction of projection welding:

• Projections are little projected raised points that offer resistance during the passage of current and thus generating heat at those points.
• These projections collapse under heated conditions and pressure leading to the welding of two parts on cooling that is multi-spot welding.
• Projection welding involves the joining of parts by a resistance welding process which closely resembles spot welding. 
• Projection welding may be carried out with one projection or more than one projection simultaneously.

Explanation:

Welding

The joining of two similar or dissimilar metals with each other. It comes under permanent fastening.

There are basically three main types:

1. Solid-state welding
2. Liquid state welding
3. Solid/Liquid state welding

1) Solid-state welding: 

• It is a group of welding processes that produces coalescence at temperatures essentially below the melting point of the base materials being joined, without the addition of filler metal. They are a homogeneous group of welding.
• No heat resources will be required but the pressure may be applied externally for welding.
• It is classified into five groups:

1. Explosive welding
2. Friction welding
3. Ultrasonic welding
4. Diffusion welding
5. Forge welding

2) Solid/Liquid state welding:

• These methods are used when the metals to be joined cannot withstand the high temperature produced in arc and gas welding.
• It is a heterogeneous group of welding.
• It is classified into :

1. Brazing 
2. Soldering

3) Liquid state welding: 

• It is a group of welding processes that produces coalescence at temperatures essentially above the melting point of the base materials being joined, with the addition of filler metal.
• They are a homogeneous group of welding.
• Heat resources will be required for welding.

Explanation:

The Oxyhydrogen flame:

Hydrogen burns in oxygen according to the reaction

2H₂ + O₂ ⇒ 2H₂O (water vapor) + 116000 cal

• The hydrogen to oxygen ratio supplied to the torch can vary between 2.5 to 1 and 6 to 1.
• Oxyhydrogen is a mixture of hydrogen and oxygen gases.
• The gaseous mixture is used for welding and brazing aluminum alloy and lower melting point alloy and for micro-welding.
• An oxyhydrogen torch is an oxy-gas torch that burns hydrogen (fuel) with oxygen (oxidizer).
• It is used for cutting and welding metal, glass, and thermoplastics.
• The temperature produced by oxy-hydrogen flame is about 2400°C
• It has been given the misleading title of water welding.

Explanation:

Welding

The joining of two similar or dissimilar metals with each other. It comes under permanent fastening.

There are basically three main types:

1. Solid-state welding
2. Liquid state welding
3. Solid/Liquid state welding

1) Solid state welding: 

• It is a group of welding processes that produces coalescence at temperatures essentially below the melting point of the base materials being joined, without the addition of filler metal. They are a homogeneous group of welding.
• No heat resources will be required but the pressure may be applied externally for welding.
• It is classified into five groups:

1. Explosive welding
2. Friction welding
3. Ultrasonic welding
4. Diffusion welding
5. Forge welding

2) Solid/Liquid state welding:

• These methods are used when the metals to be joined cannot withstand the high temperature produced in arc and gas welding.
• It is heterogeneous group of welding.
• It is classified into :

1. Brazing 
2. Soldering

3) Liquid state welding: 

• It is a group of welding processes that produces coalescence at temperatures essentially below the melting point of the base materials being joined, with the addition of filler metal.
• They are a homogeneous group of welding.
• Heat resources will be required for welding.
• 

Explanation:

Gas metal arc welding (GMAW) or Metal inert gas arc welding (MIG)

• In this process, the arc is formed between a continuous, automatically fed, metallic consumable electrode and welding job in an atmosphere of inert gas, and hence this is called metal inert gas arc welding (MIG) process.
• The shielding gases for MIG welding are mixtures of argon, oxygen, and CO2, and special gas mixtures may contain helium. 
• Direct current power supply is used to weld the workpiece.