2. When the plate thickness is less than or equal to ≤20mm, the thickness of the flat bending specimen shall be equal to the plate thickness (√).
3. For materials with the same thickness, the bending qualification rate of multi-layer welding is higher than that of single-layer welding (√).
4. The impact test of welded joints can also be used as the cold-working aging sensitivity test of welded joints (√).
5. The purpose of flattening test is to determine the hardness (×) of welded butt joint of pipeline.
6. When high-speed ions hit the metal surface, X-rays will be generated on the metal surface.
7. Dotted slag inclusion is a single black spot on the negative film, with irregular appearance, angular edges and even blackness (√).
8. Ultrasonic waves are transmitted through media (√).
9. Ultrasonic inspection is intuitive for defects (×).
10, and fluorescence test is used to detect some ferromagnetic substances (×).
1 1. The sensitivity of color test is higher than that of fluorescence test (√).
12. Fracture inspection is very sensitive to "incomplete fusion" and "poor fusion" defects (√).
13, hydrogen is easy to cause hot cracks (×) in welded joints.
14. The drying temperature for removing water absorbed by covered electrode coating is higher than100 C (√).
15. The specimen for chemical analysis of deposited metal is immersed in water, and there is no requirement for water temperature (√).
16, check whether there is water leakage, air leakage, oil leakage and other phenomena called pressure test (x).
17, welder installation work should generally be completed by welder (x).
18, the debugging process of plasma arc welding and cutting equipment must be carried out in strict accordance with its usage rules (√).
19. Only after all parts of plasma arc welding and cutting equipment are checked to be normal can debugging be carried out (√).
20. The working principle diagram and installation circuit diagram of welding machine are two kinds of electrical circuit diagrams (√) frequently used by welders and welding equipment maintenance personnel.
2 1, during electroslag welding, if the power supply is not enough, several welding power supplies can be connected in series (×).
22. The purpose of surfacing welding on the groove surface of multi-layer pressure vessel is to prevent slag inclusion and cracks (√).
23, found in the production of products with quality problems, must be scrapped (x).
24. Brittle crack is flat with metallic luster (√).
25, cracks in the structure is an important factor of brittle fracture (tick).
26. If the welding defect occurs in the stress concentration area of the structure, it has little influence on brittle fracture (×).
27, welding structure due to the strong integrity, crack is not easy to spread, so it is not easy to produce brittle fracture (x).
28, in order to prevent brittle fracture, welding structure materials should have high notch toughness (tick).
29. Insufficient material strength is the main reason for brittle failure of low voltage (X).
30. Brittle fracture is rare, so it is not harmful (×).
3 1. The welding line energy is determined by the welding process parameters (√).
32. With the increase of weld energy, the cooling rate of weldment becomes slower (√).
33. When calculating the static load strength of butt joint, consider the residual height of weld (×).
34. The calculated height of fillet weld is the center line (X) of the triangle inscribed in the weld.
35, dissimilar metal welding, arc welding is the most widely used fusion welding method (tick).
36. When austenitic stainless steel and pearlite heat-resistant steel are welded, a decarbonization zone (√) will be formed on the pearlite substrate in the fusion zone.
37, austenitic stainless steel and pearlite heat-resistant steel welding commonly used method is manual arc welding (tick).
38. The main problem of welding pearlite heat-resistant steel with ordinary low-alloy steel is that cold cracks (√) are easy to appear in the heat affected zone of welded joints.
39, who can withstand a certain pressure (not less than the design pressure) of the container is a pressure vessel (x).
40. In order to facilitate the assembly, and avoid the intersection of welds at one point, an angle (√) should be cut off on the transverse rib plate.
4 1. After welding, carry out stress-relieving heat treatment first, and then carry out mechanical correction to prevent fracture (√).
42. The preheating temperature of welded structure can be determined by carbon equivalent (√).
43. After welding, the whole weldment is tempered at high temperature, which can eliminate stress and deformation (×).
44. The hydraulic jack can be loaded in the recumbent state (×).
Answer: ×
45. The no-load voltage consumed by DC welder is greater than that of AC welder (√).
46. There are empirical methods, empirical statistical methods and empirical analysis methods to formulate working hours quota.
Second, multiple-choice question A( 1-32)
1, which does not belong to the external restraint test method for cold cracks of welded joints of carbon steel and low alloy steel is (d).
A bolt test B tensile restraint crack test C rigid restraint crack test D inclined Y groove welding crack and test
2. The welding crack specimens of oblique Y-groove are on both sides of the welding restraint weld (A-groove).
AX shape BY shape c oblique y shape DU shape
3, determine the plastic size of welded joint test is (c).
A tensile test b metallographic test c bending test d impact test
4, the same material, one-sided welding, the bending qualified angle is bigger than double-sided welding (C).
A is much bigger, B is much bigger, C is much smaller, and so is D.
5. (c) The thickness of the welded joint allows temperature measurement on its surface.
A is less than 3mm B6 mm c10mm d12mm.
6, X-ray inspection of weld defects, cracks show (b).
A sensitive b insensitive c invisible d very sensitive.
7. Most of the pores are on the negative film (b).
A angular black dot b circular or oval black dot c circular or oval bright dot d angular bright dot
8, ultrasonic flaw detection ability to identify defects (a).
A is poor, B is strong, C is generally easy to D.
9, macro fracture analysis, interception sample processing method is not correct (D).
A milling b planing c sawing d gas cutting
10, the following sample fracture can't be used for metallographic examination is (d).
A extension crack b bending crack c waste crack d gas cutting crack
1 1, covered electrode with excessive eccentricity, the defects produced during welding are incorrect (D).
A unstable arc blowing b During welding, C molten pool is not well protected, and D burns through.
12. The treatment method for the angular deformation of the sample exceeding 5 after welding is (d).
A flame correction b mechanical correction c is not allowed to correct d is invalid.
13, the test item not included in the purpose of withstand voltage test is (c).
A withstand voltage b leakage c fatigue d damage
14, ammonia test The following statement is incorrect (D).
A is more accurate, B is more efficient, and C can also be used when the environmental stability is low. D the higher the purity of ammonia gas, the more accurate it is.
15. The defect that cannot be checked in the seal inspection is (c).
A leaks water, B leaks oil, C leaks air through the air hole D.
16, which can improve the commutation condition of DC arc welding generator is (b).
A main pole b auxiliary pole c brush device d commutator
17. At present, (a) is mostly used for fillet welds connecting nozzles, cylinders and heads of multi-layer pressure vessels.
A manual arc welding b submerged arc welding CC02 gas shielded welding d manual argon arc welding.
18. The post-weld heat treatment method for controlling welding deformation of complex structural parts is (b).
A dehydrogenation treatment, B annealing and high temperature tempering, C normalizing and D quenching.
19, the welded joint of the welding procedure qualification test plate shall be subjected to nondestructive testing (D).
70% B80% C90% D 100%
20, should not be quenched steel comprehensive performance in the heat affected zone is the best (B).
A positive zone b normalized zone c partial phase change zone d melting zone
2 1, welding dissimilar metals is better than welding the same metal (b).
A is easy, B is difficult, and C is as easy as D.
22, dissimilar steel welding, the principle of selecting process parameters is mainly considered (A).
A reduces the fusion ratio, B increases the fusion ratio, C has higher welding efficiency and D has lower welding cost.
23, martensite heat-resistant steel has obvious tendency of air quenching, easy to get (A) after welding.
A martensite structure b pearlite structure c ledeburite structure d austenite structure
24. When ferritic heat-resistant steel is welded with other ferrous metals, the purpose of post-weld heat treatment is wrong (C).
A makes the welded joint uniform, B improves plasticity, C improves hardness and D improves corrosion resistance.
25, cast iron and low carbon steel welding belongs to dissimilar materials welding, the following circumstances should not reduce the fusion ratio (d).
There are many welding layers in A, the angle of groove in B is large, groove in C is open, and groove in U is D weld.
26, pressure vessel must pass (a) test in accordance with the provisions.
A hydrostatic test B mechanical performance test C corrosion test D weldability test
27, the sample is in accordance with the provisions, cut off from the test plate (D) for testing.
A weld metal b fusion zone metal c heat affected zone metal d sample
28, for carbon steel and 16MnR steel container, used in the hydraulic test should be not less than (d).
A2℃ B3℃ C4℃ D5℃
29, kerosene inspection is often used in (a) container butt weld compactness inspection.
A is not compressed, B is low, C is medium, and D is high.
30, the flame correction method of hot spot heating point diameter is not less than (b) mm.
A10mm b15mm C20 mm d25mm
3 1, the following inspection methods belong to the surface inspection is (c).
A metallographic examination b hardness test c magnetic particle examination d compactness test
32, welding positioner workbench can drive the workpiece to rotate around the axis of rotation (d).
A tilt 45 b tilt 90 c tilt 135 d plus or minus 360.
Fill in the blanks A( 1-42)
1. The tensile test of welded joint can determine the tensile strength, yield point, elongation and section (shrinkage) of weld metal and welded joint.
2. The tensile specimens of welded joints can be divided into three types: plate, round and (whole tube).
3. After the tensile test, the fracture position and (welding) defects of the specimen shall be recorded and filled in the report.
4. After the specimen is bent, the bending test in which the front surface becomes the tensile surface after bending is called (surface bending).
5. Bending specimens can be divided into two forms: flat and tubular.
6. The value of bending test is measured by (bending) angle.
7. Impact test can be used to determine the impact toughness and notch sensitivity of welded joints.
8. The purpose of flattening test is to determine the plasticity of welded butt joints.
9. At present, for boilers, pressure vessels, large ships and other important products. X-ray flaw detection is widely used as an important method to detect weld quality.
10, the core of X-ray device is a special electron tube (X-ray tube).
1 1. According to the regulations, the quality standard for radiographic inspection of steel welds is divided into (4) grades.
12. When ultrasonic waves propagate from one medium to another, they will be reflected and refracted.
13. Ultrasonic wave is generated by piezoelectric effect.
14, ultrasonic pulse reflection (flaw detector) is the full name of ultrasonic flaw detection equipment.
15, fluorescence detection is used to detect some (non-magnetic) substances.
16. When the inspected surface is defective, a red image can be displayed on white (developer).
17, and the diffusion hydrogen determination method adopts glycerol method, mercury method and gas chromatography.
18. There are five testing methods for intergranular corrosion tendency of acid-resistant stainless steel: C method, T method, L method, F method and (X method).
19. The water-based (pressure-resistant) test is called hydrostatic test.
20. The moving parts of arc welding transformer should be kept clean, flexible and free from looseness.
2 1, the main content of welding equipment inspection is the basic parameters and (technical) status of welding equipment.
22. When repairing the defects of containers with complex structure, high rigidity and deep grooves, coated covered electrode with slightly lower strength can be used as the base material.
23. Choosing the welding method with concentrated heat source (energy) is beneficial to control the welding deformation of complex components.
24, lap joint (stress) uneven distribution, low fatigue strength, is not an ideal type of welded joint.
25. When bearing supporting load, the bearing capacity of fillet weld (concave) is the highest.
26, when the temperature decreases, the toughness of the material becomes worse, at this time is easy to produce (brittle) fracture.
27, when welding by welding heat source input to the unit length of weld energy is called (welding) line energy.
28. The calculated height of fillet weld is the height of weld (inscribed) triangle.
29. When ordinary low-alloy dissimilar steels with different strength grades are welded, the strength of weld metal and welded joint should be greater than the lowest strength in welded steel, and the plasticity and impact toughness should not be lower than those of steel with lower plasticity and impact toughness.
30. The welding method in which both welding metals are melted is called (fusion welding).
3 1. When welding low-carbon steel with low-alloy structural steel, the preheating temperature should be selected according to the (low-alloy) structural steel. When low-alloy structural steel with strength grade exceeding 500Mpa is welded with low-carbon steel, the preheating temperature should not be lower than 100 degrees, and the preheating range should be about 100mm on both sides of the weld.
32. When austenitic stainless steel and pearlite heat-resistant steel are welded, the smaller the fusion ratio, the better.
33. For pressure parts of boilers and pressure vessels, certified welders can only carry out welding work within the scope of qualification.
34, pressure vessel steel carbon content is generally not greater than (0.25%).
35, compactness inspection is used to test whether there is compactness (defect) on welded joints or joints on welded containers, pipelines and closed containers.
36. According to the influence on the mechanical properties of welded joints, welding procedure qualification factors can be divided into three categories: basic factors, strengthening factors and (secondary factors).
37, welding itself should have enough strength and stiffness.
38. For important structures, the chemical composition and (mechanical) properties of each batch of steel shall be reinspected before use.
39, weldment heat treatment method generally adopts flame heating and (electric heating).
40. Before painting the finished welded structure, the surface (rust), oil stain, splash, scale and other dirt should be removed.
4 1, the man-hour quota of arc welding is determined by operation time, work place schedule, rest and physiological need time.
And (ready to end) time.
42, man-hour quota refers to the labor quota expressed in (time).
Question and answer: A( 1- 15).
1. What are the methods for evaluating crack sensitivity in variable constraint test?
Answer: Minimum strain value, total crack length and maximum crack length.
2. What is the qualification standard of flattening test?
Answer: During the test, when the distance between the outer walls of the pipe joint is pressed to a specified value, if the crack length of the tensile part of the sample is less than 3mm, it is considered that the flattening test is qualified.
3. How is ultrasonic generated?
A: But the ultrasonic wave used in the test is produced by the piezoelectric effect.
4. Briefly describe the application scope of magnetization current range?
Answer: The applicable range of magnetization current: when the thickness of the workpiece is less than or equal to 20mm, the magnetization current is 35-45 a; When the thickness of the workpiece is greater than or equal to 20mm, the magnetization current is 40-50A.
5. What is macroscopic metallographic examination?
A: Macroscopic inspection is to observe the visible tissues with naked eyes or with the help of a low-power magnifying glass on a large specimen, and you can clearly see the boundaries, incomplete penetration, cracks, segregation and seriously uneven tissues in the weld zone.
6. What is metallographic examination?
Answer: Microscopic examination is to observe the microstructure of metal with microscope, electron microscope and scanning electron microscope. So as to determine micro-defects and microstructures in the welding metal.
7. What is the purpose of measuring the hydrogen content of diffused hydrogen?
Answer: The purpose of measuring the hydrogen content in weld is to evaluate the welding method and the quality of welding materials.
8. What are the advantages and disadvantages of measuring diffused hydrogen by glycerol method?
Answer: The equipment is simple and the price of glycerol is cheap, which is conducive to popularization; Disadvantages: The viscosity of glycerol is high, some tiny hydrogen bubbles are not easy to float, and the density of glycerol is much lower than that of mercury, so hydrogen bubbles are difficult to float.
9. How many methods are there to test the mechanical properties of deposited metal?
Answer: The mechanical properties of deposited metal are tested by tensile test and impact test.
10. Briefly describe the method of kerosene test?
Answer: Apply lime water on one side of the weld; After drying, apply kerosene on the other side of the weld; Because the surface expansion force of kerosene is small; Have the ability to penetrate tiny pores; When the weld is defective, kerosene will seep out and spots or stripes will appear on the lime powder.
1 1. What are the common weldment equipments, and what are their maintenance and adjustment contents?
Answer: Commonly used welding equipment mainly refers to manual welding equipment; Its maintenance and adjustment include: installing arc welding power supply; In order to obtain large current, several arc welding power sources are used in parallel; The arc welding power supply is broken and should be repaired.
12. What kinds of circuit diagrams are the electrical diagrams divided into?
Answer: the classification of electrical diagrams: block circuit diagrams; Principle circuit diagram; Install the circuit diagram.
13. What tasks does the person in charge of the seam welder undertake?
Answer: The tasks undertaken by the seam welding head are: transmission, pressurization and conduction.
14. What is the relationship between welded joint structure and post-weld heat treatment method?
Answer: Relationship between microstructure of welded joint and post-weld heat treatment method: Different post-weld heat treatment methods will lead to different microstructure of welded joint.
15. according to the melting and compression conditions of basic metals, what are the welding methods of dissimilar metals?
Answer: The welding methods of dissimilar metals can be divided into fusion welding, pressure welding, fusion welding-brazing and liquid phase transformation welding according to the melting pressure of basic metals.
16. What is the use of the stainless steel organization chart?
Answer: The purpose of stainless steel organization chart is: When austenitic stainless steel and pearlite heat-resistant steel are welded, we can find the welding raw materials to avoid martensite structure in the weld through stainless steel organization chart, thus laying the foundation for the correct selection of raw materials before welding.
17. What is the weldability of austenitic stainless steel and ferritic steel?
Answer: Weldability of austenitic steel and ferritic steel: The main characteristics of this kind of dissimilar steel are the migration of carbon and the diffusion of alloying elements in welded joints, which leads to the reduction of low-temperature impact toughness of weld fusion lines and cracks.
18. When welding steel with nickel and its alloy, what technological measures should be taken to ensure the joint quality?
Answer: When welding steel with nickel and its alloy, the technological measures taken to ensure the welding quality are: carefully cleaning the welding materials and base metal; Reduce the melting amount of steel; Use smaller welding process parameters.
19. Why should the carbon content of pressure vessel steel be strictly controlled?
Answer: The carbon content of steel used for pressure vessels should be strictly controlled and limited: Because pressure vessels bear pressure, they often contain toxic and flammable media, and are made of steel plates, which requires good weldability of steel used for vessels. Carbon is the main element that affects the weldability of steel. When the carbon content increases, the weldability of steel deteriorates significantly and the cracks increase rapidly. Therefore, in order to ensure the quality of welded joints of pressure vessels, the carbon content of steel must be strictly controlled.
20. The overall structure of pressure vessel consists of five parts?
Answer: The overall structure of pressure vessel consists of five parts: small nozzle; Cylinder; Head; Manhole ring; Take over.
2 1. Why not use air pressure test instead of water pressure test at will? Under what circumstances can air pressure test replace water pressure test?
Answer: The reason why air pressure test can't replace water pressure test: Because air pressure test is more dangerous than water pressure test; Only when it is necessary can the air pressure test be used instead of the hydraulic test. For example, there is no trace of residual liquid in the container; A container that cannot hold liquid because of its complicated structure.
22. What are the five commonly used compactness testing methods?
Answer: The commonly used density inspection methods are: air tightness inspection; Ammonia gas inspection method; Kerosene inspection method; Hydrostatic test method.
23. Why do a large number of variable cross-section beams replace equal cross-section beams?
Answer: The reason why the beam with variable cross-section is used instead of the beam with equal cross-section: Although the beam with equal cross-section is simple in structure, convenient to manufacture and easy to realize automation, it wastes a lot of materials; In order to use metal reasonably, different types of variable cross-section beams can be designed according to the stress situation.
24. What are the cross-section combinations of welded box girder?
Answer: There are several cross-section combinations of welded structural box girders: beams composed of section steel and steel plates; Large cross-section beams welded with steel plates; Beam (bending section) assembled and welded by pressing steel plates.
25. Discuss the role of post-weld heat treatment?
Answer: The role of post-weld heat treatment: The purpose of timely tempering after welding is to make residual hydrogen escape, reduce welding residual stress and improve the microstructure of heat affected zone.
26. What are the commonly used flux recovery devices?
Answer: The commonly used flux recovery devices are: electric suction flux recovery device; Pneumatic suction magnetic flux collector, suction pressure magnetic flux collector, combined magnetic flux collector.
27. Briefly describe the composition of welding man-hour quota?
Answer: The working hour quota consists of four parts: (1) operation time, (2) arrangement time, (3) time needed for rest and physiology, and (4) preparation time.
28, briefly describes the composition of welding man-hour quota?
A: There are four parts in the working hour quota.
(1) Operation time (2) Scheduling time (3) Rest and physiological need time (4) Preparation end time.