• Post category:weld tech

The Interviewer: interview question from welding

 

 

“The Interviewer” is actually a collection of interview questions collected from several interviews and the purpose of broadcasting it is to help only those who are preparing for the interview.

Interview questions from welding

In the “interviewer” some questions are being added for the purpose of the information that may help to clarify the concept of the welding technique.

 welding 

What is welding?

In fact, welding is simply a process of joining two or more materials together with the help of heat and/or pressure.

How will you prescribe the source of heating for welding activity?

In the welding process, the base metal is heated to the melting point, requiring a certain temperature. For this purpose, sources of electrical energy or flammable gases are used.

When did the arc source begin to use?

The electric arc was first described by Dewey in England in the year 1809, but the beginning of the arc could become possible only between 1877 and 1880 with improvements in electric dynamo or generator. In 1881. August de Meritens established the arc welding process.  See Detail   Before Arc Hindi           Before Arc English

Which was the first metal that was welded?

 Refer to The First Metal

In which welding process flammable gases are used?

The flammable gases are used in the gas welding process.

How many types of flammable/fule gases are used in gas welding processes?

Acetylene, hydrogen, propane, and butane are being used as fuel gas in the gas welding process. 

Explain the gas welding process?

 Refer to the     Gas welding process.

How many types of welding processes are being used, except gas welding?

  1. Arc Welding Process
  2. Resistance Welding Process
  3. Solid-State Welding Process
  4. Thermo-Chemical Welding Process
  5. Radiant Energy Welding Process.

What are the different types of welding flame and their temperature in the Oxy-acetylene welding process?

Natural Flame: With equal proportions of Acetylene and oxygen is about 5900º F or 3200º C,

Oxidizing Flame: With increasing of the amount of oxygen, the oxidizing flame can be produced about 6300ºF

Reducing Flame:  A reducing flame has an approximate temperature of 5500ºF or 3038ºF

The temperature of flammable gases in combination with oxygen is as follows:

  • Oxyacetylene —-3200 ºC
  • Oxyhydrogen—-2500  ºC
  • Oxypropane —-2500   ºC

What is the main difference between gas welding and arc welding?

The main difference between gas welding and arc welding is the use of heat sources. Flammable gas is used to obtain the desired heat in heat source gas welding, while in arc welding an electric current is used to obtain the desired heat.

How will you define the arc welding process?

Refer to  welding processes, Arc welding

Short Interview questions asked by the Interviewer

Why do you have to leave a hole or some part of the welding while welding the pipe trunion for the pipe/reinforcement pad?

To exclude hot gas which may be generated due to welding.

How will you calculate the Current required for Welding?

Current (Amp) = [Diameter of Electrode (mm) X 40) ±20

Define the common welding defects?

The common welding defects are as follows:

  • Lack Of Penetration (Insufficient Or Incomplete Penetration)
  • Lack Of Fusion (Incomplete Fusion)
  • Undercut
  • Inclusion(Slag inclusion,Tungsten inclusion)
  • Porosity (Uniformly Scattered, Cluster, Linear, Pipe)
  • Blowhole
  • Crack (Longitudinal, Transverse, Crater, Throat, Toe, Root, Under- Bead, Heat Affected Zone, Hot, Cold Or Delayed)
  • Faulty Weld Size &Profile
  • Distortion

See Detail  Welding Defects

Define the Heat treatment in welding operation?

Refer to Heat treatments of materials

What is the test condition for welding in plate and pipe?

Refer to Welding positions

 

The Interviewer may ask these questions also

Name any two limitations of the GTAW welding process?

If tungsten is transferred to the molten metal it may become contaminated tungsten incorporation is hard and brittle

The filler rod end may cause weld metal contamination if it accidentally exits the inert gas shield.

Name any three limitations of the MMAW welding process?

There is a chance of more slag entrapment as compared other welding processes

This process is a bit slower due to the use of stick electrodes.

The machining process is difficult because of its electrode limited length and brittle flux coating.

Why is a gas shielded needed in the two types of arc processes in which it is used?

In two types of arc processes a gas shielded is used to protect the weld pool from atmospheric contamination.

The two welding processes that use gas shielded are GTAW and GMAW.

For each of the following cases state which kind of cracking is most likely to occur in a fusion-welded joint?

  1. a-A weld highly stressed during the early stage of solidification?
  2. b- a weld in hardenable steel made without pre-heat?
  3. c- a weld in an unstabilized austenitic stainless steel?

Refer to  Welding Defect Cracks

In tungsten arc welding, how should the welding arc be initiated without contact between the electrode and parent metal?

Using a High-Frequency unit with a tig torch.

Interview questions from welding joints.

Define the welding joint?

The edges of the workpieces that need to be added are called a welding joint.

How many types of joints are used in welding operation?

Following types of welding joints are used in welding operation:

  • Butt joint
  • Lap joint
  • Edge joint
  • Corner joint
  • T joint

Define the parts of the welding joint?

Part of groove weld joints

  • Groove angle
  • Bevel angle
  • Root gap
  • Root face
  • Groove face
  • Job thickness

Part of fillet weld joints

  • Leg of fillet
  • Root of fillet
  • Welding toe
  • Depth of fusion
  • Face of fillet
  • Throat of fillet