ARAMCO - CBT QC WELDING INSPECTORS INTERVIEW QUESTIONAIR FOR ARAMCO PART-3

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

Notch toughness

77) How will you calculate the geometric unsharpness in radiographic film?

Geometric unsharpness of the radiograph shall be determined in accordance with:

Ug = Fd/D

where

Ug = geometric unsharpness

F = source size: the maximum projected dimension of the radiating source

(or effective focal spot) in the plane perpendicular to the distance D from

the weld or object being radiographed, in.

D = distance from source of radiation to weld or object being

radiographed, in.

d = distance from source side of weld or object being radigraphed to film.

78) What is the welder qualification based on f number?

79) Which markers are used on SS materials?

Low halogens and Low sulfur less than 200 ppm

80) Principle of UT

Reflection of Sound

81) Principle of RT

Absorption in different materials

82) Principle of PT

Capillary action

83) Principle of MT

Magnetic flux leakag

84) What is the use of Couplant?

To remove the air gap between the transducer and object.

85) Types of Probe in UT?

Normal probe, Angular probe, triangular probe (45°, 60°, 70°)

86) Name 3 of the 5 mechanical tests in ASME IX employed for procedure & performance

qualifications?

Hardness test, toughness test, tensile test, macro examination, bend test, fillet weld

fracture test, nick break test

87) Name an NDT method and technique that employs a reflected sound beam that can be

used for the volumetric examination of welds?

Ultrasonic testing

88) List 3 disadvantages of RT over other NDT Methods.

A. Its very harmful for human being

B. high skilled interpretation required

c. access to both side required

d. parallel to the axis defects will not get

89) If a product is to be stress relieved, why is it important to use exactly the same RT

procedure before and after stress relieving?

Due to the stress relieving some types of defects will form and enlarged.

90) A dark narrow area 2-3mm wide appears on a radiograph all along the edge of the area

representing the weld. The joint has a 60-Degree double-vee groove. What is the

indication most likely to be?

Slag inclusion

91) A localized darker density Radiographic image with fuzzy edges in the center of the

width of the weld image that may or may not be wider than the width of the root pass

image is most likely what?

Incomplete root penetration

92) When the radiation source is located inside piping with the film located outside, singlewall exposure and single-wall view, name this type of exposure?

Panoramic

93) How do gamma rays compare with X-rays when applied to RT of welds?

1. Easy handling

2. High penetration

3. Low sensitivity

94) What is the Welding Process?

a) GTAW (Gas Tungsten Arc Welding)

b) SMAW (Shielded Metal Arc Welding)

c) SAW (Submerged Arc Welding)

d) FCAW (Flux Coated Arc Welding)

e) GMAW (Gas Metal Arc Welding)

f) PAW (Plasma Arc Welding)

95) Welding Position

 Pipe – 1GR, 2G, 5G, 6G,

 Plate – 1G, 2G, 3G, 4G

 PIPE:-

 1G: - A Pipe is Horizontal Position and weld beed is a vertical position.

 The Pipe will be rotated.

 2G: - A Pipe is Vertical Position and weld beed is Horizontal Position

 5G: - A Pipe is Horizontal Position and weld beed is Vertical Position

 6G: - A Pipe is a 450 Position

 PLATE:-

 1G: - Plate is Horizontal and weld is Horizontal

 2G: - Plate is Vertical and weld is Horizontal

 3G: - Plate is Vertical and weld is Vertical

 4G: - A Plate is in Overhead Position weld is Horizontal Position

96) Why we maintain the interpass temperature?

The yield and ultimate tensile strengths of the weld metal are both a function of the

interpass temperature.

High values of interpass temperature tend to reduce the weld metal strength.

Additionally, higher interpass temperatures will generally provide a finer grain structure

and improved Charpy V notch toughness transition temperatures.

97) While welding of pipe trunion to pipe/reinforcement pad you have to put a hole or leave

some portion of welding why?

For venting of hot gas which may get generated due to welding.

98) List 3 disadvantages of RT over other NDT Methods.

Radiation Safety Precautions, Planar defects not readily detectable, heavy equipment