QA/QC Saudi Arabia CBT Exam Questions Answer

1) What is the package number and explain?

 Package one stands for Distillation & Hydro treating unit.

Different units are

 91/92- High Pressure Hydro Desulphurization

 101/102- Low Pressure Hydro Desulphurization

 111/112-Naphtha Hydrotreater Unit

 151/152- Distillation and Hydro treating Hydrogen Unit

 155- Off Gas PSA Unit

 150-Hydrogen storage unit

 011/012- Crude Distillation Unit/ Vacuum Distillation Unit

2) What are the duties & responsibilities of a welding inspector?

 Perform material inspection.

 Perform consumable inspection.

 Application of inspection gauges, instruments and tools.

 Check equipment and accessories.

 Witness procedure qualification test.

 Witness welder qualification test.

 Perform visual inspection.

 Review / witness NDT

 Witness mechanical test.

 Monitor heat treatment

 Observe production and fabrication welding.

 Interpret and assure compliance to Code / Standard / Specification.

 Review technical drawing.

 Witness weld repair.

 Prepare and compile inspection records.

3) What is the formula for heat input?

a. Heat Input (j/cm)= Voltage x Amperage x 60 / Travel Speed(cm/min)

4) What are welder qualification limits?

 Base metal qualification limits. (P no. and

 Filler material qualification limits.(F No.)

 Pipe diameter and position qualification limits.

 Weld metal thickness qualification limits.

5)What is WPS?

 The WPS is a written document that provides direction to the welder

for making production welds in accordance with Code/Standard

requirements.

6) How is the Procedure Qualification Record (PQR) different from the WPS?

 Procedure Qualification Record certifies that test welds performed in

accordance with the WPS meet Code requirements and summarizes

the specific test results.

7) What is PQR?

 A record of welding variables used to produce an acceptable test

weldment and the results of tests conducted on the weldment to qualify a

welding procedure specification.

8) What are essential variables?

a. Essential Variable (Procedure) – A change in a welding condition

which will affect the mechanical properties (other than notch

toughness) of the weldment. E.g. – change in P Number, welding

process, F number, electrode, preheat or postweld heat treatment.

b. Essential Variable (Performance) – A change in a welding condition

which will affect the ability of a welder to deposit sound weld metal.

E.g - change in welding process, deletion of backing, electrode, F

number, technique etc.

9) What are supplementary essential variables?

a. The change in a welding condition which will affect the notch

toughness properties of a weldment is known as supplementary

essential variable.

10) Can we use two welding process in a WPS?

 Yes (E.g.: GTAW + SMAW)

11) What is PWHT?

 Postweld heat treatment (PWHT),defined as any heat treatment after

welding, is often used to improve the properties of a weldment.

12)Why we are using PWHT?

 To increase the resistance to brittle fracture and relaxing residual

stresses.

13) Mention the drying temperatures for low hydrogen SMAW electrodes?

 260-430°C for 2 hrs min (A5.1)

 370-430°C for 2 hrs min(A5.5)

 120-250°C for 2 hours minimum. (SS and Non-Ferrous

electrodes)

14) What do you meant by low hydrogen consumables?

 Low hydrogen consumables are defined as less than or equal to 8 ml

of hydrogen per 100 g of deposited weld metal.

15) What are dissimilar metal welds?

 Any weld joint (excluding weld overlays or strip lining) between

ferritic steel and either austenitic stainless steel, duplex stainless

steel, or nickel-based alloys, or Use of stainless steel or nickel-based

filler metals on ferritic steels.

16) Explain about 31.3?

 The piping which is generally found in petroleum refineries, chemical,

pharmaceutical, textile, paper, semi conductor and cryogenic plants, and

related processing plants.

 This section includes

a) Acceptable material specifications and component standards, including

dimensional requirements & pressure temperature ratings.

b) Requirements for design of components and assemblies, including

piping supports.

c) Requirements and data for evaluation and limitation of stresses,

reactions, and movements associated with pressure, temperature

changes, and other forces.

d) Guidance and limitations on the selection and application of materials,

components, and joining methods.

e) Requirements for the fabrication, assembly, and erection of piping.

f) Requirements for examination, inspection, and testing of piping.

19)What are the types of Mechanical tests?

 Tension Tests

 Guided Bend Tests

 Fillet Weld Tests

 Notch Toughness Test

 Stud Weld Test

20)The term used to describe delay in the production schedule to permit

inspection is __________

 Hold Point

21) Equation for Heat Input?

 H = 60EI / 1000S

Where,

 H -- Heat Input (KJ/mm)

 E -- Arc Voltage (volts)

 I – Current (Amps)

 S – Travel Speed (in/min)

22)What is the Procedure Qualification Thickness Limits?

ASME SEC IX QW – 452

i) It is the test coupon < 1¨ - Size welded (Dia)

ii)

Thickness always 2T – T – Thickness of Test Coupon

iii)

Minimum Thickness Qualified – 1.5mm

23)What are the essential variables for PWHT?

 Heating rate

 Temperature attained

 Choking temperature and

 Cooling rate.

24)What is the gap of socket weld?

 1.5 mm to 3 mm

25)Formulae for carbon equivalent?

 CE = C + (Mn)/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

26)What do you mean by ITP?

 It is a mandatory item in the Quality Plan to guide and assure

quality in a specific type of work in a specific sequence of QC

activity steps.

27)What is NCR?

 NCR: (Non Conformity report): A record reporting the variation from the

specified requirements.

28) How do you calculate the weld repair percentage?

 % RR = (Lr/Lw) X 100

 Where, % RR – Percent repair rate

Lr -- Total length of repair in one week

 Lw --Total length of weld radiographed in one week

29)RT % of M, D, Normal and Sever cyclic service?

 D Service : a) if rating is ≥ 1500 lb, 100 % RT

b) If MDT ≤ -29ºC, 5% RT

c) Hydrocarbon service, 100%

 M service : a) if rating is ≥ 600 lb, 100 % RT

b) If MDT ≤ -29ºC, 20% RT

c) Hydrocarbon service, 100%

 HP Service : 100% RT

 SC Service : 100% RT

30) What should be the distance b/w two parallel welds?

 20mm or three times the wall thickness of the joint, whichever is

greater.

31)What factors (give at least four) are taken into account when selecting and

designing a joint for a welding application?

 Strength

 Accessibility for welding

 Minimize distortion

 Cost of welding

 Accessibility for inspection

32)What is the difference b/w stud bolt and machine bolt?

 Machine bolt has a head on one side and nut on other side but stud bolt

have nuts on both sides.

33)Which standard do you refer for the welding equipment calibration?

 BS 7570.

34)What are the tests required for verifying supplementary essential variables?

Notch toughness tests-

 Charpy V- Notch test

 Drop weight.

35) What is the chemical composition of a low hydrogen electrode – E7018?

 E7018 – C 0.15, Mn 1.60, Si 0.75, P 0.035, S 0.035, Ni 0.30, Cr 0.20,

 Mo 0.3, V 0.08.

36) What does L stands for 316L and the composition?

 Low Carbon.

37) Mention the drying temperatures for low hydrogen SMAW electrodes?

 260-430°C for 2 hrs min (A5.1)

 370-430°C for 2 hrs min(A5.5)

 120-250°C for 2 hours minimum. (SS and Non-Ferrous

electrodes)

37) What are the different factors that cause HIC?

 A sensitive microstructure

 A sufficient level of hydrogen

 A high level of stress

38)What is the minimum thickness of pipe that requires stress relieving to be

done as per B31.3?

 19 mm

39) What is the function of shielding gas?

 Stabilises the arc roots on the material surfaces.

 Ensures smooth transfer of the molten metal from the wire to weld

pool.

 Forms the arc plasma.

40)If welder is qualified in 3G position in pipes, he can weld all

position?

3G position in pipe not mentioned in ASME Sec IX,

The pipe positions are 1G, 2G, 5G and 6G as per ASME Sec IX