1. After the brazing is completed, the vacuum unit should be shut down immediately.
Correct Answer: False.
2. Pulse MIG welding at 0It is less widely used in butt welding of steel plates below 8mm, while pulse TIG brazing can be as small as 0Butt welding of 3mm ultra-thin plate (suspended flat welding, no backing plate).
Correct Answer: True.
3. A metal composed of two or more elements is called an alloy.
Correct Answer: False.
4. Before vacuum brazing, it is necessary to ensure sufficient circulating cooling water and water pressure to meet the needs of the equipment.
Correct Answer: True.
5. Carbon arc gouging is a method of planing metal by using the high temperature of the carbon arc to melt the metal and then blowing off the molten metal with compressed air.
Correct Answer: True.
6. When the electrode bath furnace is working, most of the current flows through the molten salt between or near the electrodes, converts it into heat energy and forms a high temperature there, and then transmits it outward. Therefore, the temperature field of the electrode bath furnace has a lot to do with the electrode arrangement.
Correct Answer: True.
7. Soldering is completed in two steps, first wetting the metal surface with the brazing metal, and then filling the gaps between the surfaces.
Correct Answer: True.
8. In a vacuum environment, metal is not easy to volatilize.
Correct Answer: False.
9. Dust and oil precipitation on the inner wall of the compressor cylinder, air storage barrel, air duct, etc. should not cause the compressor to burst.
Correct Answer: False.
10. Brazing in inert atmosphere furnace has become the mainstream brazing process in the aviation industry.
Correct Answer: False.
11. The vacuum brazing furnace generally uses two vacuum gauges with different ranges, rather than a composite vacuum gauge with a wide range of ranges.
Correct Answer: False.
12. The metal bonding mechanism of pressure welding and brazing is exactly the same.
Correct Answer: False.
13. The difference in the arrangement of internal atoms leads to the difference in the properties of crystalline and amorphous.
Correct Answer: True.
14. If the valve of the oxygen cylinder catches fire, as long as the operator closes the valve and cuts off the oxygen, the fire will be extinguished by itself.
Correct Answer: True.
15. Inorganic squirting agent has strong corrosiveness.
Correct Answer: True.
16. The top-buried electrode handle is buried vertically downward into the wall of the bath, and its lower end is connected with the electrode, so it is not easy to leak salt, and the structure is relatively simple.
Correct Answer: False.
17. The frequency of high-frequency power supply is high and the heating is rapid.
Correct Answer: True.
18. When the induction ring is working, the tube can only be cooled by oil.
Correct Answer: False.
19. The ability of metal materials to resist the corrosive effect of oxidizing atmosphere at room temperature is called oxidation resistance.
Correct Answer: False.
20. Sodium hydroxide can corrode plastics.
Correct Answer: False.
21. The transmission speed of the conveyor mechanism of the continuous brazing furnace mesh belt is not adjustable.
Correct Answer: False.
22. The main safety points of induction brazing are anti-electric shock and anti-radiation.
Correct Answer: True.
23. Electroslag welding is an efficient welding method for large-thickness workpieces.
Correct Answer: True.
24. Touching the exposed metal parts of the equipment that are not electrified, such as metal shells, metal shields and metal frames, will not be electrocuted.
Correct Answer: False.
25. The greater the impact energy, the better the toughness of the material.
Correct Answer: True.
26. When using cardiac resuscitation for first aid, after pressing and blowing for half a minute, the method of "seeing, listening, and trying" should be used to re-judge whether the electrocuted person has resumed natural breathing and heartbeat.
Correct Answer: False.
27. The safe production of brazing operations can eliminate or control dangerous and harmful factors.
Correct Answer: True.
28. According to the different mixing ratios of oxygen and acetylene, oxygen-acetylene flame can be divided into three types: neutral flame, carbonization flame and oxidation flame.
Correct Answer: True.
29. Usually the induction ring is made of copper alloy tube.
Correct Answer: False.
30. In flame brazing, gas flux is often used as flux.
Correct Answer: True.
31. The source of danger refers to the root cause or state that may cause injury, disease, property damage, damage to the working environment or other losses.
Correct Answer: True.
62. The melting temperature of gallium-based brazing metal is 106℃~29.8 between.
Correct Answer: True.
33. The barreled oxidant shall not roll on the cement floor.
Correct Answer: True.
34. The brazing equipment in the furnace is mainly resistance furnace.
Correct Answer: True.
35. The drier the human body, the greater the resistance.
Correct Answer: True.
36. The electrode of the embedded electrode salt bath furnace is drawn out from the lower wall of the furnace, which can significantly reduce the effective use volume of the furnace and reduce the amount of furnace loading compared with the plug-in electrode salt bath furnace.
Correct Answer: False.
37. In the process of using cardiac resuscitation, the breathing and pulse of the electrocuted person should be determined again every few minutes by the method of "seeing, listening, and trying", and the time for each judgment shall not exceed 5s 7s.
Correct Answer: True.
38. Acetylene is decomposed into carbon and hydrogen under the action of heating, and then the carbon reacts with the oxygen in the mixture to form carbon monoxide, forming the first stage of acetylene combustion in oxygen.
Correct Answer: True.
39. Hydrochloric acid is the most commonly used solution to remove scale and rust.
Correct Answer: True.
40. When repairing cast iron, the wire planting method can effectively prevent the weld from peeling.
Correct Answer: True.
41. The temperature of the inlet and outlet of the vacuum brazing cooling water should be lower than ().
a:25 b:65 c:45
Correct answer: B
42. When employees find hidden dangers of accidents or other unsafe factors, the wrong practice is ().
A: The personnel who receive the report should be placed and then processed B: Immediately report to the on-site safety production management personnel or the person in charge of the unit C: The personnel who receive the report should be dealt with in a timely manner.
Correct Answer: a
43. The requirements of the insulation standard must be met between the live parts of the welding machine and between the shell and the ground, and the resistance value shall not be less than () m.
a:1 b:2 c:3
Correct Answer: a
44. The surface of the ** after metallization becomes rough and hard, and brass will cause the skin color to be ().
A: Blue-green B: Gray-yellow C: Yellowish-brown.
Correct Answer: a
45. During resistance brazing, () will lead to the growth of matrix grains, the evaporation of low-boiling point elements in the brazing metal, and the decomposition of the brazing agent.
A: The heating speed is too fast B: The heating speed is too slow C: The current is too small.
Correct answer: B
46. Regarding salt bath brazing, the wrong of the following statements is ().
A: Salt bath brazing is mainly used for soft brazing of workpieces B: Salt bath brazing uses molten salt as the heating medium of the workpiece C: Most of the bath salts commonly used in production are chloride, fluoride and cyanide and other salts.
Correct Answer: a
47. Single-layer steel plate can be used to make () type furnace shells.
A: Large B: Medium C: Small.
Correct answer: c
48. When pipelines, valves, water seals and other devices are frozen, it is strictly forbidden ().
A: Steam heating and thawing B: Hot water defrosting C: Baking over an open flame.
Correct answer: c
49. The nitrate bath furnace belongs to ().
A: High temperature bath furnace B: Medium temperature bath furnace C: Low temperature bath furnace.
Correct answer: c
50. The soft brazing method of brazing using the latent heat of the vapor released when the saturated vapor pressure condensation of the liquid is used as a heat source for brazing is called ().
A: Scratch brazing B: Steam bath brazing C: Brazing in furnace.
Correct answer: B
51. In order to protect the lead vapor, the maximum allowable concentration of lead smoke in the air of the workshop is ()mg.
a:0.08 b:0.03 c:0.05
Correct answer: B
52. The text of the roof light of the vehicle transporting hazardous chemicals and the sign that must be hung on the rear of the vehicle is ().
A: Pay attention to safety B: Keep a distance between vehicles C: Dangerous goods.
Correct answer: c
53. Substances with chemical ** occurrences are not included according to their characteristics ().
A: Gasoline B: Explosives (gunpowder) C: ** mixture formed by combustible substances and air.
Correct Answer: a
54. In the following description of highly toxic drugs, the wrong one is ().
A: It is not allowed to be stacked in the open air B: It cannot be stored in glass bottles C: It must be sent and received by two people.
Correct answer: B
55. The bearing material of the turntable automatic induction brazing machine is ().
A: Carburized rubber B: Asbestos cement C: High manganese steel.
Correct answer: B
56. The industrial name of sodium carbonate with 1 crystal water is ().
A: Heavy alkali B: Light alkali C: Soda ash.
Correct Answer: a
57. At present, the preheating method basically adopted by the wave soldering machine is ().
A: Heat conduction B: Thermal radiation C: Heat convection.
Correct answer: B
58. Generally, it does not become inflamed or suppurated, but often causes local numbness and loss of consciousness in the form of electric shock ().
A: **Metallization B: Electromagnetic field C: Electrobranding.
Correct answer: c
59. When resistive brazing, the voltage that cannot be selected is ()v.
a:380 b:110 c:220
Correct answer: B
60. Among the following cases, they are definitely not caused by electromagnetic field injuries ( ).
A: Menstrual disorders B: **metallization C: Hair loss.
Correct answer: B
61. Sodium hydroxide belongs to ().
A: Strong base B: Strong acid C: Weak base.
Correct Answer: a
62. After handling highly toxic chemicals, it should be ().
A: Rest B: Eat to replenish your energy C: Wash your hands with running water.
Correct answer: c
63. The tolerance when determining the maximum secondary short-circuit current value of the welding machine in an indirect way is ()%.
a:5 b:-10 c:10
Correct answer: B
64. China's current fire protection regulatory system does not include ().
A: Fire Protection Laws B: Criminal Regulations C: Fire Protection Regulations.
Correct answer: B
65. In arc brazing, when other conditions remain unchanged, the brazing metal changes from the vertical position to the backward welding method ().
A: Decreased penetration, small splash B: Increased penetration, small splash C: Increased penetration, large spatter.
Correct answer: B
66. Sufficient time is necessary for the solder and the substrate to diffuse each other and form a firm bond, and the welding time and the welding current () complement each other.
A: Yes within a certain range B: No C: Absolutely.
Correct Answer: a
67. The maximum secondary short-circuit current value of the resistance brazing machine is ()a.
a:600 b:900 c:1200
Correct answer: c
68. The elements that can improve the cutting performance of metal materials are ().
A: Silicon B: Manganese C: Sulfur.
Correct answer: c
70. The wrong thing about the fire extinguishing mechanism of water is ().
A: Suffocation B: Cooling C: Wet.
Correct answer: c
70. When destroying a large number of flammable and explosive chemicals, the consent of the local supervisory authority shall be obtained.
A: Chemical B: Public Security and Fire C: People**.
Correct answer: B
71. Measures that do not belong to the prevention of electric shock accidents are ().
A: The electrical box door should be locked, keep the internal wiring neat, configure the fuse according to the regulations, and strictly configure one machine, one box, one gate and one leakage B: The construction site can be slightly higher than the standard height to build machinery and equipment C: If the building or scaffold is too close to the outdoor high-voltage line, a protective net should be added according to the specification.
Correct answer: B
72. After the brazing is completed, before turning off the mechanical pump, ensure that the oil temperature of the diffusion pump is lower than ().
a:40 b:80 c:60
Correct answer: B
73. The carbon content of cast iron commonly used in industry is generally in ().
a:1.5% to 25% b:2.5% to 40% c:4.0% to 50%
Correct answer: B
74. Vacuum brazing is mainly used for the welding of () materials.
A: Low melting point B: Easy to oxidize C: High hardness.
Correct answer: B
75. Sufficient time is necessary for the solder and the substrate to diffuse each other and form a firm bond, and the welding time and the welding current () complement each other.
A: Yes within a certain range B: No C: Absolutely.
Correct Answer: a
76. The core content of the Work Safety Law is correct ().
A: Five basic legal systems B: Tripartite operation mechanism C: Two combined regulatory systems and three major countermeasure systems.
Correct answer: c
77. The methods for determining the symptoms of "feigned death" of electric shock are "looking", "listening", and "trying". where "test" refers to ().
A: Test the breathing airflow in the mouth and nose with your hands or a small piece of paper, and then use two fingers to gently press the carotid artery in the depression next to the Adam's apple on one side to see if there is a pulsatile sensation B: Test the breathing airflow in the mouth and nose with your hand or a small piece of paper, and then touch the pulse at the wrist with your hand to see if there is a pulse C: Test the mouth and nose with your hand or a small piece of paper for breathing airflow, and then touch the heart with your hand to see if there is a beat.
Correct Answer: a
78. The management personnel of the warehouse where hazardous chemicals are stored must be equipped with reliable ().
A: Labor protection supplies B: Safety monitoring instruments C: Portable fire-fighting equipment.
Correct Answer: a
79. Inhalation of higher concentrations of hydrogen fluoride gas or vapor can seriously irritate the mucous membranes of the eyes, nose and respiratory tract, resulting in bronchitis and bone lesions.
A: Not sure Yes B: Yes C: No.
Correct answer: B
80. The following description of sulfuric acid is correct ().
A: Monobasic acid B: Tribasic acid C: Dibasic acid.
Correct answer: c
81. After the welding machine is finished working below 0, the methods for dealing with the cooling water in the cooling pipe are ().
A: Heating volatilization B: Hanging itself outflow C: Compressed air blows out the cooling water in the cooling line.
Correct answer: c
82. For most workpieces, the appropriate clearance is () when pre-applying the brazing department.
a:≤0.025mm b:≥0.025mm c:0.025mm
Correct Answer: a
83. The generally recognized "lead-free" means that the mass fraction content of lead in electronic products does not exceed ().
a:0.3% b:0.2% c:0.1%
Correct answer: c
84. The oxidation and corrosion resistance speed index of superheater tubes and other materials is generally controlled at () mm d.
a:0.01 b:0.10 c:0.05
Correct answer: B
85. In arc brazing, when other conditions remain unchanged, the brazing metal changes from the vertical position to the backward welding method ().
A: Decreased penetration, small splash B: Increased penetration, small splash C: Increased penetration, large spatter.
Correct answer: B
86. The description of nitrogen is wrong ().
A: Chemically inactive B: Can be directly combined with carbon and oxidation C: Can be combined with some metals or non-metals.
Correct answer: B
87. A certain gap should be maintained between the induction ring and the weldment.
A: Keep air circulating B: Avoid heating too fast C: Avoid short circuit.
Correct answer: c
88. Ammonia is easily cured into ().
A: Snowy solid B: Strip solid C: Lumpy solid.
Correct Answer: a
89. The main components of gas during brazing in reducing gas furnace are ().
A: Carbon dioxide B: Hydrogen C: Chlorine.
Correct answer: B
90. The following description is wrong ().
A: Carbon dioxide is not soluble in water B: Carbon dioxide is slightly denser than air C: Solid carbon dioxide is commonly known as dry ice.
Correct Answer: a
91. The inclination angle at which the maximum penetration depth can often be obtained by the backward welding method in arc brazing is ().
a:25° b:15° c:5°
Correct Answer: a
92. When vacuum brazing, the oil level of the mechanical pump and the diffusion pump should be compared with the indicated horizontal line.
A: Not higher than B: Quite C: Not less than.
Correct answer: c
93. In vacuum brazing equipment, the () structure is easy to cause mechanical injury.
A: Heating system B: Measurement and control system C: Vacuum system furnace body.
Correct answer: c
94. Minimize the gap between the induction ring and the weldment is ().
A: Prevent heat loss B: Improve thermal efficiency C: Avoid short circuits.
Correct answer: B
95. The maximum secondary short-circuit current value of the resistance brazing machine is ()a.
a:600 b:900 c:1200
Correct answer: c
96. The most widely used aluminum alloy in welded structures is ().
A: Anti-rust aluminum B: Forged aluminum C: Duralumin.
Correct Answer: a
97. The gas and oxygen produced after the calcium carbide is in contact with water are mixed and burned, and the maximum temperature that can be obtained is ().
a:2000 b:2600 c:3200
Correct answer: c
98. The following () cannot protect against direct electric shock.
A: Install residual current action protector B: Install high-current socket C: Install leakage switch.
Correct answer: B
99. After increasing the electrode pressure, the application of () measures cannot reduce its influence on the strength of the weld.
A: Increase the welding current B: Extend the welding time C: Reduce the welding time.
Correct answer: c
100. Combustible dust** mainly occurs in ().
A: Inside the production equipment B: Inside the container C: Inside.
Correct Answer: a