I. Single selection issues
1. Which of the following welding methods does not belong to welding? ( )
A. Manual arc welding b. Air welding c. Electrical welding d. Welding
Answer: c
2. When welding, the total name(s) of the parameters selected to ensure the mass of the welding。
Welding process parameters b. Welding process c. Welding methods d. Welding materials
Answer: a
3. When welded arc, the reason for the bite is (...)。
A. Welding over too small b. Welding too slow c. Long arcs too slow d. Transport strips too slow
Answer: c
4. Fire oxide in welding flames applies to welding。
Carbon steel b. Stainless steel c. Copper d. Cast iron
Answer: c
The usual welding number(s) for co2 gas protection。
A. H08mn2sia b. H08a c. H13crmoa d. H10mnsi
Answer: a
When welding is used ( ) different polarity will have different process effects。
A. Straight current b. Communication c. Pulse current d. Square wave current
Answer: a
The most dangerous flaw in the welding is (...)。
Air hole b. Slag c. Fragmentation d. Unmelted
Answer: c
8. During welding, the wind speed in the welding room shall be less than (...)。
A. 8m/sb 5m/sc. 3m/sd. 1m/s
Answer: d
9. When welding, there must be a certain safe distance between the human body and the body carrying the electrical. When humid and electrocution is more dangerous, the safe distance should not be less than (...)。
A. 0. 5 m b. 0. 6 m c. 0. 8 m d. 1 m
Answer: d
10. Welding sites shall maintain the necessary passages, and the width of the footlines shall be no less than (...)。
1m b 1. 5m c. 2m d. 2. 5m
Answer: b
Ii. Multiple options
Welding methods can be classified according to the characteristics of their process(s)。
A. Melting welding b. Pressure welding c. Welding d. Welding
Answer: abc
2. The components of welds are (...)。
A. Weld core b. Pills c. Painting d. Welding
Answer: ab
3. Welding process parameters for manual arc welding primarily include (...)。
Welding diameter b. Welding currents c. Welding voltage d. Welding speed
Answer: abcd
4. Welding equipment consists mainly of (...)。
A. Oxygen cylinder b. Acetylene cylinder c. Depressors d. Welding torches
Answer: abcd
The characteristics of co2 gas protection welding are (...)。
A. High weld productivity b. Low welding costs c. Welding deformations d. Strong rust resistance
Answer: abcd
6. Welding has some advantages。
B. Welding quality c. Welding conditions d. Welding in various locations
Answer: abc
The basic forms of welding are (...)。
A. Connecting b. T., c., corner, d. Connect
Answer: abcd
Weld defects can be divided by their position in the welding。
B. External defects c. Surface defects d. Root defects
Answer: ab
Safety techniques during welding consist mainly of (...)。
Electrical safety b. Fire protection against blast c. Radiation protection d. Drug protection
Answer: abcd
10. The main measures of labour protection in welding are (...)。
A. Personal protection b. Ventilation c. Blocking d. Isolation
Answer: abcd
Iii. Questions of judgement
Welding is a process by which welding is combined with heat or pressure, or both, and the atoms are combined with or are not filled with materials. ( )
Answer:
The larger the diameter of the welds, the smaller the current of the welds. ( )
Answer: x
The distance between the oxygen cylinder and the acetylene cylinder shall not be less than 5 m when welded. ( )
Answer:
4. The greater the flow of carbon dioxide gases, when welded, the better. ( )
Answer: x
5. Welding is used to protect welding metal, metallurgical treatment and improve welding. ( )
Answer:
6. Welding is generally less intense than the parent. ( )
Answer: x
The gas hole is an empty hole formed by the gas in the smelt during welding that was not released before the metal condensed and left behind in the welding. ( )
Answer:
8. Toxic gases generated during welding are mainly ozone, nitrogen oxides, carbon monoxide and hydrogen fluoride. ( )
Answer:
9. Welding sites should be kept dry and free of water. ( )
Answer:
10. Welders should be operated in working clothes, hats, gloves and insulation shoes. ( )
Answer:
Iv. Brief answers
1. Briefly describe the rationale for manual arc welding。
Artisanal arc welding is the process of welding, using the heat generated by electrical arc discharge, which melts the welding with the welding and then welding after condensing, thereby obtaining a strong joint. When welded, welds and welds are used as two electrodes, respectively, creating arcs between them. The high temperature of the arc causes welds and welds to melt locally and form a melting pond. As the arc moves forward, liquid metals in the melting pond gradually cool down and condensate into welding。
2. Briefly describe the type and scope of application of weld flames。
Welding flames are divided into neutral, oxidized and carbonated flames. Welding of most metals, such as carbon steel, purple copper, etc., by neutral fire; welding of flames, such as brass and copper, by virtue of their high oxidity; and carbon fire with a certain reduction and carbon seepage effect, such as welding of materials such as high carbon steel, cast iron and rigid alloys。
3. Briefly describe the advantages and disadvantages of protecting the welding of carbon dioxide gases。
Advantages: weld productivity is high, which is 1 - 4 times higher than manual arc welding; welding costs are low, about 40 - 50 per cent of the welding and manual arc welding; welding is small and thermal impact is narrow; welding is strong, with low hydrogen content and high frack resistance. Disadvantages: welding is larger and welding is not good enough; it is difficult to weld with communication power and complex equipment; it is not possible to weld where there is wind; the welding process is better arc light and smoke is larger。
4. Brief description of the cause of gas holes during welding and of preventive measures。
Causes: welds or welds have impurities such as oil and rust on their surfaces; welding is too large or too small; electric arcs are too long; welding is too fast; gas is poorly protected, etc. Precautionary measures: pre-weld cleaning of welds and weld surfaces; selection of appropriate welding currents and weld speeds; control of the length of the arc; guarantee of gas protection; drying of welds, etc。
Topics for discussion
1. Discussion of options for different welding methods for application in actual production。
In actual production, the choice of welding methods requires a combination of multiple factors. For some small, complex-shaped welds with high weld quality, manual arc welding is highly flexible and can be welded in various locations, often for maintenance and single-piece production. Welding is efficient and of good quality and is widely used for large-scale production of long and straight welding and ring welding in larger diameters. Welding of co2 gases is suitable for welding sheeting and medium-heavy sheeting structures, which are more applied in such industries as automobile manufacturing and engineering machinery. Welding is used to weld thin steel plates, non-ferrous metals, etc., such as welding on bicycle frames。
2. Discuss the importance of weld quality control and the main measures。
Weld quality control is essential and directly relates to the safety, reliability and useful life of the product. The poor quality of welding can lead to defects in welding, such as cracks, gas holes, reduced structural strength and safety accidents. The main control measures include rigorous pre-weld inspection of welds and welding materials to ensure that they are of the required quality; selection of appropriate welding process parameters, such as welding currents, voltage, speed, etc.; enhanced quality control during welding, such as the use of non-destructive tests; and increased skill level and quality awareness of welders and strict enforcement of welding protocols。
Discussion of the need for welding safety protection and the main protective measures。
Welding is necessary because of a variety of risk factors during welding, such as electrocution, fire, explosion, radiation, toxic gases, etc. The main protection measures include electrical safety protection, such as the use of qualified welding equipment and ensuring good terrain; fire protection against blasts, such as cleaning of inflammable materials around the site and equipping with fire suppression equipment; radiation protection measures, such as the use of protective masks, clothing, etc.; anti-virus measures, such as enhanced ventilation, gas masks, etc.; and personal protection, such as gloves, insulation shoes, etc。
4. Discussion of ways and means of improving the efficiency of welding production。
Improving the efficiency of welding production can begin in many ways. In terms of process, the selection of appropriate welding methods, such as automated welding, can significantly increase productivity; optimize welding process parameters and reduce welding time. In terms of equipment, the degree of automation and reliability of equipment is enhanced by the introduction of advanced welding equipment. At the personnel level, welding training is enhanced to improve its operational skills and proficiency; production plans are rationalized to reduce the amount of time spent on equipment. In addition, productivity could be improved by improving weld design, reducing unnecessary welding, improving the quality of welding and reducing the number of repeat repairs。
