ARAMCO考试题知识分享.doc

ARAMCO考试题

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Questionnaire and Answer Sheet: MECHANICAL GENERAL 1
机械综合 1
1. What is the purpose of a penetrameter or IQI?
Indicates radiographic sensitivity and quality of the techniques.

To find the smallest defect.

2. What is meant by the term sensitivity with regard to radiography?

The ability of a radiographic technique to reveal defects of a specific size.

3. What are the limitations of magnetic particle inspection and liquid penetrant inspection?
M.T. can be used only on ferromagnetic materials to detect surface subsurface discontinuities.
L.T. can be used to detect defects open to the surface.
Both M.P. and L.P. require surface preparations before testing.

1) magnetic material
2) surface and sub surface
3) Surface finish(scale oil )

4. What information is contained in a Welding Procedure Specification?
Process type, groove (joint) design, material type, material thickness, position of groove, filler metal type, pre-heat requirements, interpass temperature, post weld heat treatment requirements, shielding gas or flux type, electrical characteristics, techniques of welding.

Essential and non-essential variables.

5. Why is post weld heat treatment required for some type weldments?

Relieve stresses, adjust hardness

6. What is the basic difference between a DIN and an ASME penetrameter?

DIN penetrameter has a wire type penetrameter, 7 wires
ASME penetrameter is a wire type penetrameter. 6 wires

7. What type of defects would you expect to find during visual inspection of a completed weld?

Undercut, excessive or insufficient weld reinforcement, lack of penetration, lack of fusion, porosity, slag inclusion cracks, weld spatter, etc.
incomplete penetration on a single butt-weld, weld spatter, etc..

8. What precaution must be taken with low hydrogen welding electrodes?
Store in oven when not in use, kept in heated container by welder awaiting use.

9. What information normally appears on radiography?

Penetrameter identification, Location of markers to ensure complete coverage, the name of the inspecting laboratory, the date, the part number, whether original or subsequent exposure.

10. What is the code require amperage for the dry, prod method of magnetic particle inspection?

90-110 amps/inch for <19mm
100 – 125 amps / inch.for >19mm

11. What materials are the transducer (search unit) (crystal) made from?

Quartz, Barium Titanate, Lithium Sulphate and Ceramics.

12. What is a film defect (artefact)?
A mark on the film usually caused by improper handling or processing.

Artefact, water mark, finger print, any bad operation.

13. If you were inspecting an item using the prod method and located a weak crack pattern, where would you place the prods to obtain a stronger location?

Relocate prods 90 degrees to the crack pattern and re-inspect.

14 What typical defects would you expect while inspecting a casting?
Sand and slag inclusions, gas porosity, shrinkage, hot tears.

15. Describe the pulse echo technique.
When an electric current is applied to the crystal, the crystal vibrates transforming the electric energy into mechanical vibrations which are transmitted through a coupling medium into the test material as high frequency sound waves. These pulse vibrations propagate through the object and are reflected as echoes from both discontinuities and the back surface of the test piece and will appear as a vertical deflection on the cathode ray tube or oscilloscope.

The prob make sound wave, though the material, reflect by the wall & defect, and indicate on the sceen.

16. Which method i.e. magnetic particle examination or liquid penetration examination, locate non-metallic inclusions open to the surface.

Both.

17. What is a “Procedure Qualification Record?

Listed are the “essential variable” of the specific process of processes. It is a record lf the parameters of the test weld.
It supports the range of values on the WPS.

18. What is meant by the term “Film Density”?

Measurement of film blackening.测量或胶片的发黑度。
Densitometer is used to measure film darkening. 显像密度计是用于测量胶片的暗色变化。

19. What factors determine the echo height of a flaw in ultrasonic inspection?

Size of the flaw, its type, position or orientation and instrument characteristics.

20. What surface preparation is required on a material before magnetic particle or liquid penetrant inspection?
The material surface should be clean, dry and free from oil, grease, weld spatter or anything that will obscure or interfere with defect detection. Clean 1” from each side.

Questionnaire and Answer Sheet: MECHANICAL GENERAL 2

机械综合 2
1. What is a mil?“Mil”是什么？
1/1000 inch, 0.001” or 0.0254mm.

2. Difference between stress relieving and normalising.

1) Stress relieving was not to refining the grain structure, but normalising dose.
2) Stress relieve dose not alter mechanical property of material, but normalising dose.

3. Name 2 tests carried out to determine toughness.

D.W.T.T., CHARPY impact test.

4. What is max. hardness valve as per NACE MR 0175?

Low carbon steel 235 Hv max. (21 HRC max) 钢 最大：235 Hv

5. How would you measure gramophone lines (水线) on a raised face of a flange?

Depth guage.

6. Name 3 types of flanges face.

Plain face, Raised Face, RTJ.

7. What precautions must be taken when welding cladded pipe?
Check angle, Prep etc. when welding ensures slag is removed and freed of beads etc.

8. What info is required on a standard mill cert?

Cast number, Chemical Analysis, Mechanical property test result, P.O. Number, Client. Test Results etc.

9. Why is radiography preferred over other N.D.T. methods?
Permanent indications on SPAM.
RT give a record.

Questionnaire and Answer Sheet (MAGNETICAL PARTICLE TESTING)
磁粉检验
1. Can heat have an effect on the results of a magnetic particle test?
YES是的 ( 1, magnetic change, 2. water or dye dry)

2. How does the appearance of a surface defect differ from that of a subsurface defect?
Surface defects have a more clear and distinct indication and are easier to detect, they can also be re-tested by PT method. Subsurface defects are detectable by MT-Method (most reliable method is “wet fluorescent” after A.C. magnetizing) keep in mind the skin effect when using AC current

3. TRUE or FALSE: A coil shot produces what is generally considered to be a longitudinal magnetic field.
TRUE (apply the right hand rule)

4. As per ASME Section V, what amperage should be used for the dry prod exam of base metal?
For thickness below ¾”>> 90-110 Amp/25mm for thickness above ¾”>> 100-125 Amp (refer to ASME Section V)

5. Surface defects are more clearly defined by A.C. or D.C. current.
By A.C.

6. TRUE or FALSE: Discontinuities parallel to the magnetic field produce the strongest indications
FALSE, best case is 90° to the magnetic field lines.

7. TRUE or FALSE: It is possible to detect defects by magnetic particle examination that cannot be detected by radiography.
TRUE, for example, by x-ray method using an Iridium 192 source, you will not detect very small
Cracks, called “hair cracks”. Those kinds of defects can be found by MT-wet fluorescent method, on the surface or close to the surface.

8. What method is more sensitive for the detection of subsurface defects, AC or DC current?
DC. 　
9. According to ASME Section V. what are the three main steps in a magnetic particle examination?
Cleaning up the test surface, magnetizing of the component and application of the according test medium i.e. dry powder or fluorescent suspension, evaluation and record the results.

Clean, test, report.

10. TRUE or FALSE: When parts are to be welded after magnetic particle testing, residual magnetism may attract the filler material. This aids in the disposition of weld metal improving the weld quality.
False

11. TRUE or FALSE: A longitudinal magnetized part retains a more objectionable residual field than a circular magnetized part.
TRUE

12. TRUE or FALSE: Demagnetization is still required when a part will be subsequently heat treated.
FALSE

13. TRUE or FALSE: The detection of subsurface defects over ¼” deep in weldments is more of a problem than is the case of surface defects.
TRUE正确

14. When a magnetic field is induced in a part with prods, spaced 6 inches apart, the field is considered as: a) solenoid field b) distorted circular field c) longitudinal field d) yoke field
b)

15. TRUE or FALSE: Abrupt changes in thickness, high amperages and drilled holes near the test surface are causes of non-relevant indications.
TRUE正确

Questionnaire and Answer Sheet RT (RADIOGRAPHY TESTING)
射线检验
1. What is the purpose of a penetrameter?

To indicate the quality of radiological images.
The ability of showing the smallest defect.

2. What are the minimum and maximum acceptance levels, per ASME Section V, for film density using a gamma-ray source and single film viewing?
1.8-4.0 for x-ray, 2.-4.0 for gamma-ray

3. Name five (05) attributes which are normally included in a written radiographic procedure.

Material thickness, isotope or X-ray source, minimum source to object distance, maximum source size, film type and manufacturer, required sensitivity, radiographic technique,

4. Name at least 5 types of weld defects would you expect to find with Radiography.

Hi-Lo, porosity, slag inclusion, tungsten inclusion, lack of penetration, lack of fusion, cluster gas pores, offset, burn through isolated inclusion,

5. What American standard specifies the qualification requirements for technicians involved in nondestructive testing?
ASNT, SNT-TC-1A and CP-189

6. TRUE or FALSE: ASME Section VIII, div. 1 contains radiographic acceptance criteria for rounded indication.
True

7. In a double wall technique for single wall viewing, what is the minimum number of exposures required by ASME V?
Three exposures taken 120 deg. to each other

8. Source size, specimen thickness, and source to object distances are three factors that determine the ______________________________ of a radiograph?
Ug-(Geometric unsharpness) Sensitivity灵敏度

9. What does ASME V say about quality of radiographic film?
All radiographs shall be free from mechanical, chemical, or other blemishes to the extent that they do not mask and are not confused with the image of any discontinuity in the area of interest.

10. A radiographic film having wide latitude also has, by definition: a) poor definition b) low contrast c) high
speed d) none of the above.
b　low contrast低的对比度
胶片的种类很多，ACFA C7 D7 C4 D4 （D4比D7晶粒度细，更清晰）, FOSI 1x80 1x100 1x 150
对比度月底，灵敏度月底。Latitude 越高contrast 越低。
11. TRUE or FALSE: To make a proper evaluation when interpreting a radiograph, it is necessary to know the welding process used to make the weld
True正确

12. A dark line of varying width on a radiograph which follows the edge of the fusion zone of a weld cap is indicative of: a) undercutting b) incomplete fusion c) porosity d) shrinkage
A

13. A radiograph that shows a narrow dark line traveling in irregular directions would generally indicate the presence of: a) a crack b) slag line c) aligned porosity d) lack of fusion
a- crack 裂缝

14. TRUE or FALSE: Radiographic film with large grain size will produce radiographs with better definition than film with small grain size.
False 错误

15. TRUE or FALSE: Deep scratches in lead screens result in corresponding dark lines on the radiograph.
True 正确

Questionnaire and Answer Sheet UT (ULTRASONIC TESTING)
超声检验
1. What is the first step in a UT examination? 超声检验的第一步是什么？

Read and understand the procedure, calibration of test unit, check the test surface condition.

2. Why is surface condition critical?
The longitudinal or transverse waves, produced by the test probe have to penetrate into the material, possibly without any loss of wave energy and to avoid UT-echoes on the screen, caused by a rough surface, which can result in miss-interpretation of the echoes. To eliminate those and to support a proper wave penetration into the material, in any case, it must be applied a kind of Gel or alternative medium with a similar viscosity, onto the test surface prior commencement of scanning the surface with the test probe.
Uneven surface can impede sound transfer and create non-relevant indications.

3. What is the most common method to check for cracks in a weld using UT?

Shear wave (angle beam testing) technique

4. Higher frequency transducers are generally better suited for: a) castings b) forgings c) neither
b) Forgings

5. Define sensitivity
To calibrate the UT-Test Unit in conjunction with the calibration / reference block, i.e. “K1” or “K2”, you have Unit amplification for example of 12dB, this is the calibration sensitivity. To have a better resolution for detection of irregularities, you put on top another 3dB for transfer correction and another 3dB for compensation of wave pressure reduction occurred by the steel micro structure. This increase of 6dB means that the test or scanning sensitivity is doubled. Upon detection of a defect, you have to reduce the 6dB correction for further evaluation acc to the negotiated acceptance criteria.
The ability of ultrasonic test system to locate flaws of a know size specified in the referencing code.

6. Define resolution
The resolution depends on correct choice of test unit incl. choice of test transducer, proper calibration incl. all above mentioned correction compensations, test surface condition, depth -type – size -characteristic of defects.
Resolution is the ablitity of an ultrasonic system to differentiate between two reflectors.

7. Which transducer provides greater sensitivity and resolution: a) low frequency b) high frequency c) expensive transducers.
b) High frequency, due to the shorter wave length.

8. TRUE or FALSE: Ultrasonic is the preferred method for examining clad plate for lack of bonding.
TRUE 正确

9. List at least three types of defects can be detected by ultrasonic testing?
Lack of bonding, none metallic inclusion, porosity / pores, overlaps
Lack of fusion, cracks

10. What level of certification must an ultrasonic test operator, working independently, have as a minimum?
For plate and bar stock ferro materials, using longitudinal wave technique: Level 1 required, for testing of weld connections using shear wave technique, testing of austenitic: Level 2 required.
When working independent and evaluating and classifying UT flaws level 2 is required
Level 2 was required.

11. When examining materials for planar flaws oriented parallel to the part surface, what test method is most often