Monday, 1 May 2017
Competency Evaluation & Interview Tool for Specific Evaluations for Welding/Mech QC Candidates
Rate Technical Knowledge (Mechanical, GC-12)
1. Describe the difference between QA & QC?
Answer: Quality Control is the operational techniques (Inspection, Examination & Testing) that are used to fulfill requirements for quality. Quality Assurance is the system of action and planning needed to provide confidence that a Product or Service will satisfy quality requirements
2. What do quality system audits evaluate?
Answer: The degree of quality system conformance to established requirements.
3. Saudi Aramco has adopted the basic framework and definitions of the International Quality System Standards ISO-9000 Series. This has been done to provide universal understanding and improve communication between the COMPANY and prospective CONTRACTORS whose Quality System is congruent with the ISO-9000 Series. Describe the basic elements of an ISO 9000 Series Quality Program?
Quality Systems per ISO-9001, 9002, 9003
4. What is an essential variable as related to a Weld Procedure Specification (WPS)?
Answer: A change in a welding condition that will affect the weld’s mechanical properties.
5. What is the relationship between a Procedure Qualification Record (PQR) and a WPS?
Answer: The PQR documents what occurred during the welding and testing of the test coupon.
6. Heat input (SMAW per ASME IX) is a combination of what two electrical characteristics & travel speed?
Answer: Voltage and Amperage
7. Excessive heat input is mainly attributed to what poor welding techniques during SMAW process?
Answer: Excessively wide weaving and slow travel speed.
8. What are 3 potential sources of Hydrogen encountered during SMAW process?
Answer: Moisture in the metal and electrode coating, oil, elemental Hydrogen in the base metal
9. What are several likely causes of porosity in carbon steel welds using the SMAW process?
Answer: Poor welding technique and equipment, excessive wind, moisture & weld contaminants.
10. What dimension is measured to determine the size of a concave fillet weld?
12. What dimension is measured to determine the size of a convex fillet weld?
13. Where would cracking most likely occur from excessive current input in a single pass weld?
Answer: Centerline of the weld
14. Using GTAW process, describe what happens to a weld without proper purging/back gassing on SS material?
Answer: Oxidation at the ID (Sugaring)
15. Name 3 of the 5 mechanical tests in ASME IX employed for procedure & performance qualifications?
Answer: Tension, Guided Bend, Fillet-weld, Notch-toughness & Stud-weld tests
INTERVIEW ATTACHMENT w/ANSWER KEY
Rate Technical Knowledge (Mechanical, GC-12)
16. How is Magnetic Particle inspection of a weld using the wet continuous test method performed?
Answer: The particles (usually fluorescent) are sprayed, poured on or applied by immersion and the magnetizing current is applied while the particles are still flowing.
17. Indications with Liquid Penetrant Testing are easily seen if the surface has been prepared by grinding prior to testing? True/false? Why?
Answer: False, because grinding can smear metal and mask/cover discontinuities.
18. Name an NDT method and technique that employs a reflected sound beam that can be used for the volumetric examination of welds?
Answer: Ultrasonic Testing using Shear Wave Technique provides good volumetric exam coverage.
19. List 3 disadvantages of RT over other NDT Methods.
Answer: Radiation Safety Precautions, Planar defects not readily detectable, Heavy equipment
20. If a product is to be stress relieved, why is it important to use exactly the same RT procedure before and after stress relieving?
Answer: So that a baseline evaluation is performed to ensure that borderline indications are not misinterpreted after stress relief.
21. 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?
Answer: External Undercut
22. 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?
23. Name 5 common film artifacts that may be cause for rejection of Radiographic Film?
Answer: Film Scratches, light leaks, chemical stains, fogged film, static marks, water marks, streaks, crimp marks, finger marks, lint, dirt
24. When the radiation source is located inside piping with the film located outside, single-wall exposure and single-wall view, name this type of exposure?
25. How do gamma rays compare with X-rays when applied to RT of welds?
Answer: Gamma rays have greater penetration ability, but give poorer contrast.
26. Per ASME B31.3 (assume latest edition), name three of the four Categories of Fluid Service?
Answer: Categories D, M, High Pressure & Normal
27. Per ASME B31.3, who is responsible for classification of service to a given category?
Answer: The Owner
28. Per ASME B31.3 (assume latest edition), what are the RT requirements for Socket welds in severe cycle service?
29. Relating to the above question, Give good reasons why random RT of socket welds is recommended?
Answer: Both gross welding defects & poor quality welders can be identified, with repairs and corrective action taken, & Gap can be verified.
30. Briefly describe good QC practice relating to the installation & bolting of flanges?
Answer: Verify Materials (type, size and rating) are acceptable, gasket verification & good bolting practices (torque value requirements met) in accordance with approved procedures.
31. What is an often-overlooked Inspection/NDT requirement on the installation of an orifice flange?
Answer: Visual weld inspection of the seal weld & NDT has been missed prior to bolting of flanges
32. Per ASME Section VIII, Div. 1, can a nozzle to be attached to the exterior surface of a pressure vessel without any portion of the nozzle projecting into the shell?
Answer: Yes, with many restrictions
33. Explain the difference between a 2:1 Ellipsoidal head and a hemispherical head?
Answer: A hemispherical head has no flange and knuckle region and holds greater volume.
34. Which of the above two heads given equal thickness can withstand greater internal pressure?
Answer: The 2:1 elliptical head can withstand much more internal pressure given equal thickness.
35. In ASME Section VIII, Division 1, Parts UW and UCS cover what scope of work?
Answer: UW designates requirements for pressure vessels and vessel parts fabricated by welding, and UCS designates requirements for pressure vessels and vessel parts constructed of carbon and low alloy steels.
36. Name several Inspection items on internal component/tray installation for new columns?
1. Drawings, Calcs & Data review
2. Verification of Material Construction of Internal components (tray assemblies & systems, hardware, packing medium)
3. Location, levelness and orientation of internal components per Mfg. Drawings/tolerances.
4. Seams, holes, gaps, missing items, looseness of hardware in trays
5. Leakage Tests as needed for trays, troughs, weirs, etc.
6. Final Cleanliness of Tray Assemblies
37. What API documents apply to the replacement of an existing floor for an Aboveground Oil Storage tank?
Answer: API 653 & API 650
38. What are two key items to be resolved prior to addition of new nozzles to older tanks per API 653?
Answer: Tank Material identification, Material Design Considerations & selection (need for shell insert).
39. Briefly describe an area impressed Cathodic Protection System?
Answer: Electrical current & use of selectively placed sacrificial anodes is employed to stop/slow the electrochemical reaction that occurs during the corrosion process.
40. Relating to Contractor Weld Shop evaluation prior to the beginning of pipe welding for a major project, what are several key items you would look for as the Inspector assigned to approve the shop for Company?
Answer: 5M + E formula = Manpower, Methods, Materials, Machines, Measurement, Environment
1. Manpower=Ensure adequate Personnel that are trained, qualified, certified & approved
2. Methods=Ensure that standards are followed and that welding procedures, special processes (PMI, PWHT, etc) are acceptable and that there is a good quality system (paper trail) in place.
3. Materials=Ensure Materials are approved, certified, documented (traceable), stored correctly with area for deficient items (quarantined), and segregation of dissimilar metals.
4. Machines=Ensure Equipment is adequate for the intended work and in good working condition.
5. Measurement=Ensure Contractor QC Program & testing/calibration program is in place for equipment and work.
6. Environment=Ensure that the working environment (building) is safe, sheltered from the elements and adequate to ensure quality work.
Per SAES-W-011 (show section where information is found, review with candidate)
1. What is the maximum size of low Hydrogen (E7018) permitted?
2. What are the diameter limitations (per pipe size) for different welding processes?
3. a) What is the requirement (Material, location) for bridge tacks?
b) In what must bridge tacks be contained to avoid the need for Surface Method NDT?
4. a) For temporary supports and attachments welded to the pipe, what are requirements related to Material?
5. What is the maximum amount of time that E-7018 electrodes can be kept out in the field?
6. What is the minimum drying temperature and drying time?
7. How many times can electrodes be rebaked?
8. What is the maximum internal misalignment of butt joints?
9. Piping during preparation before fit up shall be cleaned/ground internally/externally for what distance from the edge of the prepared joint?
10. Moist surfaces require moisture removal and surfaces to be preheated must be preheated to what distance from the joint edge?