This article is about Welding Inspector CBT Questions related to topic of Welding Inspection on Vessel Fabrication as per Aramco or International Standards.
Welding Inspector CBT Questions | Welding Inspection on Vessel Fabrication
SAIC-W-2068 – Welding Inspection on Vessel Fabrication
Document required at welding station:
- All weld joint shall be marked for identification by a weld number & welder symbol and made with suitable weather proof marking material.
- The markings shall be placed in location such that they will be easily observed and remain visible for a time suitable for SAPID.
ROTATING EQUIPMENT ALIGNMENT:
Vertical Angular Mis-Alignment
- (+) Reading, add shim to FF
- (-) Reading, remove shim to BF
Horizontal Angular Mis-Alignment
- (-) Reading, move BF to the right
- (+) Reading, move BF to the left
Vertical Parallel Mis-Alignment
- (+) Reading, remove shim to all feet
- (-) Reading, add shim to all feet
Horizontal Parallel Mis-Alignment
- (-) Reading, move all feet to the right
- (+) Reading, move all feet to the left
ALIGNMENT TYPES
1. Rim (Radial) and Face (Axial) Method
R= radial A= Axial
2. Reverse Rim (Dial) Indicator Method
R= radial
ALIGNMENT FIXTURES
1. Brackets – should be rigid to minimize sag.
2. Dial Indicators – shall be calibrated.
3. Wrenches.
GENERAL REQUIREMENTS
1. Alignment bracket shall not be used to rotate the equipment.
2. Reading shall be at 90 degree increments in the horizontal and vertical plane.
3. Readings to be considered valid, the readings and zero shall repeat within 0.02mm (1mil). The algebraic sum of the horizontal readings shall be equal to the algebraic sum of the vertical reading within 0.05mm (2mils).
4. Reverse dial (rim) alignment shall be performed while turning both shaft at the same time in the direction of rotation.
5. Rim and face alignment is recommended when the coupling hub is greater than the spacing between indicators or one end of the train elements cannot be turn.
6. When the shaft cannot be rotated, micrometer measurement wit an accuracy of 0.01mm (0.5mil) are to be used. These can be asked in Welding Inspector CBT Questions.
FINAL ALIGNMENT TOLERANCES
1. All piping is disconnected.
2. Fixed and movable shafts free to move.
3. Maximum five shims under any support.
4. Shim 300 series stainless steel or better material not laminated and flat to 1/1000. At least 3 mm (0.125 in) but not more than 12 mm (0.5 in) under movable machine foot. No more than one ≥3 mm (≥ 0.125 in) thick under any foot.
5. Shim are full bearing.
6. Bolts are not undercut.
7. Washer are not lock washer and do not yet yield when hold-down bolt are tightened.
8. Hold-down bolts are not bolt bound and reasonably centered in bolt holes.
9. Soft-foot is not more than 0.05mm (0.002in).
10. Pipe Strain checks made in accordance with procedure in Chapter 6-Piping; section 4 par. 1.8.1 through 1.8.5. API 686/REIE 686.
ALIGNMENT PROCEDURE
1. Indicate and Record Rim (Radial) Reading @ 6:00 Oclock
2. Indicate and Record Face (Angular) Reading @ 6:00 Oclock
3. Use Formula to compute the shim
+ sign means shaft is low so add shim
– sign means shaft is high so remove shim
Formula: S1 = ±R/-2 + ±F × B / A → S1 = B/A × F + R/2
S2 = ±R/-2 + ±F × C / A → S2 = C/A × F + R/2
Where:
S1 = shim needed under Front foot
S2 = shim needed under Rear foot
R = rim reading at the bottom
F = face reading at the bottom
4. Install or Remove Shim as required
5. Repeat 1 & 2 as needed. If reading is within tolerance the alignment is satisfactory.
CLEANING (SEAS-L-350)
1. During project proposal and detailed design, detailed procedures for cleaning and flushing of the piping spool and systems shall be established identifying acceptable methods.
a. All pipes shall be internally cleaned by air blowing prior to installation.
b. Chemical or Vapor or Foam Cleaning after hydrostatic pressure testing to remove oil, grease, preservatives, rust and mill scale per approved procedures. (refer to 01-SAMSS-017, SAES-G-116 and SAEP-1024).
2. Pressure Testing of the piping systems shall be in accordance with SAES-A-004 and SAES-L-150.
3. Lay Up Requirements after cleaning and pressure testing has been completed shall be in accordance with SAES-A-007.
4. All piping systems shall be flushed using high pressure (60.8mPa/8.8ksi) jet such as rotating hose or rotating nozzle.
5. Below 4” use High Velocity Water Flushing (HVWF) with a minimum of 3m/s velocity.
Flushing medium shall be plant/process water or raw water.
6. When flushing stainless steel lines, the chloride ion content shall be less than 50mg/l. After flushing it should be completely drain, dried to a dew point below 1°C and protect against
corrosion.
7. Pneumatic Flushing with dry air (dew point – 1°C or less) or steam with a minimum exit velocity of 15m/s.
8. Pressurized Air Shock Blowing (PASB) for initial cleaning for instrument air, plant air and as an alternative method cleaning method for initial cleaning of small bore pipe (less than 2 inch), working pressure shall never be more than 810 kPa (115 psi).
9. Alignment of flange joints with spectacle plate is within the following tolerances:
a. Vertical bolt hole offset ± (2.4mm + 30%) = ± 3.12mm.
b. Horizontal bolt hole offset ± (2.4mm + 30%) = ± 3.12mm.
c. Rotational offset ± (2.4mm + 30%) = ± 3.12mm.
d. Combination of vertical, horizontal and rotational offset ± 3.12mm.
WELDING – ASME SEC.IX
– A weld – is a union of materials produced by heat and or pressure
– A joint – is a configuration of members
Types of Common Welds
1. Butt weld.
2. Fillet weld.
3. Spot weld.
4. Seam weld.
5. Edge weld.
Types of Common Joints
1. Butt joints.
2. Tee joints.
3. Lap joints.
4. Open corner joints.
5. Close corner joints.
Weld Preparation
1. Single bevel butt weld.
2. Single vee butt weld.
3. Single J butt weld.
4. Single U butt weld.
Normally made on thinner materials when access from both sides are restricted.
5. Double bevel butt weld.
6. Double vee butt weld.
Normally made on thicker materials when access from both sides are unrestricted
7. Double J butt weld.
8. Double U butt weld.
5 Acceptable Heat Treatment of Process Piping
1. Enclosed furnace.
2. Local flame heating.
3. Electric resistance.
4. Electric induction.
5. Exothermic chemical reaction
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