CSWIP 3.1 - Heat Input

Question 1.

Which of the following is the correct arc energy minimum and maximum, if the amps are (250-300), volts (25-28) and travel speed (250-300) mm/minute by MMA welding?

• 1,0 - 1,5 (kJ/mm)

• 1,0 - 1,6kJ/mm)

• 1,25 - 2,0 (kJ/mm)

• 1,5 - 2,0 (kJ/mm)

Answer explanation

The correct arc energy for MMA welding with the given parameters falls within 1,25 - 2,0 kJ/mm, as this range accounts for the specified amps, volts, and travel speed, ensuring optimal welding performance.

Question 1a.

With reference to the previous question and the correct answer, what the minimum

and maximum heat input?

• 1,0 - 1,5 (kJ/mm)

• 1,0 - 1,6 (kJ/mm)

• 1,25 - 2,0 (kJ/mm)

• 1,5 - 2,0 (kJ/mm)

Answer explanation

The correct choice, 1,0 - 1,6 (kJ/mm), indicates the range of heat input that is acceptable based on the previous question's context, ensuring it meets the specified criteria.

Question 2

During the MAG welding of a test piece for the purpose of approving a WPS the following parameters have been recorded: Amps 300, Volts 30, ROL 250mm, time 1 minute.

What is the heat input value?

• 1.808 KJ/mm.

• 2.055 KJ/mm.

• 1.728 KJ/mm.

• 2.16 KJ/mm.

Answer explanation

Heat input is calculated using the formula: Heat Input (KJ/mm) = (Volts x Amps x Time) / (60 x ROL). Substituting the values: (30 x 300 x 1) / (60 x 250) = 1.728 KJ/mm. Thus, the correct answer is 1.728 KJ/mm.

Question 3.

The specimen for hardness test shall be taken from which of position when doing the welding HL045?

• PB

• PA

• PE

• PC

Answer explanation

The hardness test specimen for welding HL045 should be taken from position PE, as this area is critical for assessing the weld's mechanical properties and integrity.

Question 3a.

With reference to the above question and the correct answer, what is the reason?

• Highest heat input

• Lowest heat input

• K=1

• K=0.8

Answer explanation

The correct answer is 'Lowest heat input' because lower heat input typically leads to more efficient energy use and reduced thermal stress, making it the preferred choice in many applications.

Question 4

What is the thermal efficiency factor of SAW?

• k=1,0 (AE= HI)

• k=0.8

• k=0,5

• k=0,6

Answer explanation

The thermal efficiency factor of SAW is represented as k=1.0 (AE= HI), indicating maximum efficiency. Other options like k=0.8, k=0.5, and k=0.6 represent lower efficiencies, making k=1.0 the correct choice.

Question 4a.

With reference to the above question and the correct answer, what is the definition of thermal efficiency factor:

• Efficiency factor is Arc energy x 100% / Heat input

• Efficiency factor is Heat input x 100% / Arc energy

• Efficiency factor is Heat input / Arc energy

• Efficiency factor is arc energy / heat input

Answer explanation

The correct definition of thermal efficiency factor is 'Heat input x 100% / Arc energy'. This formula indicates how effectively the heat input is converted into useful arc energy.

Question 5.

Heat Affected Zone (HAZ)

• Higher strength

• Higher hardness

• Lower toughness

• Lost of corrosion resistance

• All of the above

Answer explanation

The Heat Affected Zone (HAZ) experiences changes in material properties due to heat. It typically results in higher strength, higher hardness, lower toughness, and loss of corrosion resistance, making 'All of the above' the correct choice.

Question 5a.

With reference to the above question and the correct answer, what is the

meaning of HAZ?

• The Hardest region

• The area who receives heat on the fist time and faster cooling rate

• The one where the heat concentrated

• a and b correct

Answer explanation

HAZ refers to the area that receives heat first and has a faster cooling rate, which affects material properties. This choice accurately describes the characteristics of HAZ, making it the correct answer.

Question 6.

Arc Strike?

• Arc Strike are the local damages to the surface of parent metals adjacent to

  weld.

• High hardness

• Potentially crack

• Brittle

• All of the above are correct

Answer explanation

Arc Strike refers to local damages near the weld, characterized by high hardness, potential cracking, and brittleness. Therefore, all the provided options are correct, making 'All of the above are correct' the right choice.