[Lương Phi]

1. What is the effect of tempering after quenching
   a. Toughness and strength are increased.
   b. Toughness and strength are reduced.
   c. Toughness reduced and strength increased
   d. Toughness increased and strength reduced
   e. Toughness increased and hardness increased

2. What is the possible effect of having the heat input too low during welding?
   a. Low toughness, entrapped hydrogen and low hardness.
   b. High hardness, lack of fusion and entrapped hydrogen.
   c. Entrapped hydrogen, low toughness and high ductility.
   d. Lack of fusion, low toughness and a reduction in ductility

3. Which of the following is the most likely to be considered an essential variable for a welder qualification test?
   a. A change from an electrode classified to BS EN 499 as an E46 3 INI B to an electrode classified to AWS A5.1 as an E7018.
   b. A change of pipe wall thickness by at least 15 mm.
   c. A change in pre-heat temperature from 50oC to 100oC.
   d. A change from PC welding position to PA welding position.
   e. All of the above.

4. Which of the following is most likely to increase the chance of solidification cracking?
   a. Reduction in sulphur content of the parent material
   b. Increased restraint on the joint during welding.
   c. Increase in weld hydrogen content from 15 ml/100 g to 25 m/l100 g.
   d. Poor through thickness ductility in the materials being welded.
   e. Both a and b.

5. When considering the advantages of site radiography over ultrasonic inspection which of the following applies?
   a. A permanent record produced good for detecting lack of sidewall fusion in a single U butt weld and defect identification.
   b. A permanent record produced, good for the detection of all surface and sub-surface defects and assessing the through thickness depths of defects.
   c. Permanent record produced, good for defect identification and not as reliant upon surface preparation.
   d. No controlled areas required on site, a permanent record produced and good for assessing pipe wall thickness reductions due to internal corrosion.
   e. Both a and c

6. Austenitic stainless steel can be identified by:
   a. Very shiny appearance.
   b. Lack of magnetic attraction.
   c. Its extreme hardness.
   d. None of the above

7. Which of the following flame types would you expect to be used for the cutting of mild steel?
   a. Carburising flame.
   b. Oxidising flame.
   c. Reducing flame.
   d. Neutral flame.

8. Cold lapping is another term for:
   a. Lack of fusion at the toe of a weld.
   b. Lack of fusion between weld metal and weld metal.
   c. Undercut at the toe of a weld.
   d. Both a and b.

9. On a single-V butt weld, the distance through the centre of the weld from root to face is called:
   a. Reinforcement.
   b. Penetration.
   c. Throat thickness.
   d. None of the above

[Lương Phi]

10 The HAZ associated with a fusion weld:
a. Can not be avoided.
b. Usually has the highest tensile strength.
c. Is usually martensitic.
d. Both a and b.
e. All of the above.
11. Which of the following butt weld preparations would normally be considered for a mechanized welding process
a. Single-V butt, root gap 2.5 mm (welded from on side only).
b. Double-V butt-welded both sides, root gap 2.0 mm.
c. Single-U butt with backing.
d. None of the above can be used for mechanized welding.
12. Which of the following applies to the heat treatment process of tempering
a. It is always carried out at a temperature above upper critical limit.
b. It is carried out to increase the strength and toughness of weldments.
c. Tempering is generally carried out before quench hardening.
d. None of the above
13.The usual method of assessing the sensitivity and density of a radiograph is by means of:
a. Densitometer and dosimeter.
b. Penetrameter and a densitometer.
c. IQI and a dosimeter.
d. IQI and a fluxmeter.
14. Hot cracking in steel weldments occurs:
a. Along the fusion line.
b. In the last metal to solidify.
c. Weld centre line
d. In areas of the lowest dilution.

[Toan Dinh Phu]

Theo em:
1.d
2.b
3.a
4.e
5.c
6.b
7.b
8.d
9.c

[Hiền]

Theo mình là :1D, 2D, 3A, 4E, 5E, 6B, 7D, 8A, 9C

[WIC]

1. What is the possible effect of having the heat input too low during welding?
   a. Low toughness, entrapped hydrogen and low hardness.
   b. High hardness, lack of fusion and entrapped hydrogen.
   c. Entrapped hydrogen, low toughness and high ductility.
   d. Lack of fusion, low toughness and a reduction in ductility

Đáp án đúng là B nhé em.
--> Answer B: Low HI > high Travel Speed > high hardness, LOF, and entrap H2.

[Hiền]

Thật sự thì em cũng phân vân B và D nên pick đại , em thấy D cũng ok . Low HI > fast cooling > susceptible microstructure > low toughness + reduce ductility.

[bien]

Câu này, không phải lúc nào Low HI thì low toughness cả.
Khi nào high HI thì ảnh hưởng lớn nhiều đến low toughness.

[Bien]

Mình gợi ý trả lời như sau:
1. Toughness increased, hardness decreased.
2. B.
3. B, thay đổi dãy thickness > 12mm thì dãy qualify khác. Các thông số còn lại áp dụng cho WPS.
4. B, (A- sai, vì giảm S thì giảm Solidification Crack).
5A. / 6B. / 7D. / 8A. / 9C. / 10E. / 11C. / 12D. / 13B. / 14C.

Lần sau anh em trao đổi nên đưa ra cái đáp án của chính mình, để mọi người góp ý. Không nên đưa cả thớt câu lên như thế được gì thì được, không được thì thôi. Hy vọng anh em kết nối vì mục đích chia sẽ và hỗ trợ, cũng như nhận hỗ trợ.

[Toan Dinh Phu]

Câu 14 em nghĩ là A, vì nứt nóng không 100% luôn luôn xuất hiện ở trung tâm đường hàn.

[Bien]

Câu 14: đáp án A không phù hợp em nhé. đường Fusion line nằm phía HAZ chứ k phải ở giữa. Cơ chế nứt nóng thường là centerline em ah.

[Bien ND]

Phi ơi, đáp án của em như thế nào? em đưa ra nhé. Format của TWI hình như không có 5 câu trả lời.

[Author]

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