2. Understand the common welding defects and welding deformation.
3. Understand the basic principle of oxygen cutting, the process of gas cutting, the conditions of metal gas cutting and the application of gas cutting.
4. Understand the safety technology of manual arc welding and gas cutting.
5. Initially master the manual arc welding arc initiation and surfacing wave operation technology.
6. Have a general understanding of the welding production process of typical welded structures.
Second, the internship content
1. Manual arc welding: arc initiation, surfacing wave and butt welding.
It is required to master the arc initiation technology skillfully, and the arc initiation position should be accurate, and master the operation essentials of surfacing welding wave and butt welding preliminarily, so that the weld can be formed well. No welding is needed.
2. Gas welding and gas cutting: ignition and fire extinguishing, gas welding flame adjustment, surfacing wave and manual gas cutting of medium-thick low-carbon steel plate.
It is required to be able to ignite and extinguish fire, to distinguish three kinds of oxyacetylene flames, and to adjust to a neutral flame with appropriate size, and to understand the operation essentials of flat welding wave in gas welding reactor. Manual gas cutting operation is to deeply understand the process and basic principle of oxygen cutting. Note that the workpiece metal does not melt during the whole gas cutting process, so the cut is narrow and uniform. It is best to cut the cast iron plate again by gas cutting, and pay attention to observe different phenomena.
Three. field operation
1 manual arc welding
1. Manual arc welding process
Observe the manual arc welding operation. Do you know what manual arc welding is? What equipment and welding materials will be used? The general situation of manual arc welding is illustrated with simple pictures, including power grid connection, circuit breaker (switch), welding machine, electrode holder, covered electrode, arc, workpiece and weld.
2. Hand arc welding machine
(1) Understand the types and general structure of hand arc welding machine, welding machine model and its main technical parameters, and the use of welding machine (wiring and current regulation). ).
② Observation and performance: Both AC welder and DC welder adopt J507 welding, and compare their arc stability. Write down the observed phenomena and conclusions.
3 covered electrode
(1) Understand the composition of covered electrode, the functions of each part, the types of covered electrode, the meaning of structural steel covered electrode brand and covered electrode specifications (covered electrode diameter).
② Observation and performance: Weld with bare wire and covered electrode, and compare the difficulty of arc initiation, arc stability, splash and weld quality (whether there are oxides and pores on the weld surface, etc.). ). Write down different phenomena.
③ Observation and performance: Both alkaline covered electrode and acidic covered electrode are welded by AC welder, and their arc stability is compared. Write down different phenomena and conclusions.
④ When visiting welding production, pay attention to observe and compare the slag removal performance of alkaline covered electrode and acidic covered electrode.
4 manual arc welding process
① Understand the four common joint types and four common groove types of butt joint, the size parameters of groove and their functions. Visit butt welding, fillet welding and multi-layer multi-pass welding.
② Understand the process parameters and selection of manual arc welding, and what are the different phenomena and results of welding with different current and different speed.
③ Visit the welding of welds in different spatial positions: flat welding, vertical welding, horizontal welding, overhead welding and pipeline all-position welding. Pay attention to the differences of welding process parameters and operation methods, and compare the differences of welding quality, productivity and working conditions.
5 hand arc welding operation technology, viewing performance:
(1) striking and friction arc striking methods. Understand the main points of operation: Use wrist force to lift and lower covered electrode.
(2) Surfacing wave technology. Pay attention to its operation essentials.
③ Sawtooth strip conveying mode.
(4) butt welding. Understand the whole process: material preparation-groove processing-cleaning before welding-assembly-tack welding-welding-cleaning after welding-inspection.
6. Understand the safety technology of manual arc welding.
7 welding defects and inspection methods.
① Observe welding defects, understand the characteristics of defects such as incomplete penetration, burn-through, blowhole, slag inclusion, crack, undercut and flash, and analyze their causes (from the aspects of pre-welding preparation, welding process parameters, operation technology, etc.).
② Watch the common inspection methods and their applications: color inspection, magnetic particle inspection, X-ray inspection, ultrasonic inspection and water pressure test.
8 welding deformation
Understand the common basic forms of welding deformation and their correction methods (mechanical correction and flame correction), and watch the correction process.
2 gas welding and gas cutting
1 gas welding process
Observe the gas welding operation. Know what gas welding is? What gas is used for gas welding? What equipment and devices should be used for gas welding? What welding material should be used? Draw a sketch of gas welding work, including the connection between gas welding equipment and gas path, and indicate the names of each part.
2 gas welding equipment, know five kinds of gas welding equipment:
(1) The function, structure and working principle of acetylene generator, and the safety technology of using acetylene generator.
② Function, structure and working principle of temperature regulating fuse.
(3) The function of the oxygen cylinder and its safety technology.
④ Function, model, structure and working principle of pressure reducer.
⑤ Function, model, structure and working principle of welding torch.
3 gas welding materials-gas welding wire and gas flux, understand:
① Brand and function of welding wire. Specification and selection of welding wire.
② Function, brand and application examples of gas welding flux.
4 gas welding flame
① Observe the characteristics and adjustment of three kinds of oxyacetylene flames.
② Understand the temperature distribution of gas welding flame. Observe that the heating speed of welding wire or steel plate is different when it is placed in different parts of neutral flame. It is concluded that the temperature and heat in different parts of neutral flame are different.
(3) when visiting gas welding production, we should pay attention to the use of different oxyacetylene flames when gas welding different metal materials. Write down examples.
5 observe the gas welding operation technology
(1) Ignition and fire extinguishing methods.
② Gas welding of low carbon steel: flat welding, thin plate left welding and thick plate right welding. Understand its operation essentials, pay attention to nozzle angle, flame height, heating temperature, welding speed and welding wire addition method.
(3) When gas welding cast iron, pay attention to the characteristics of welding materials and welding process (such as preheating). ).
6 understand gas welding safety technology
7 oxygen cutting
① Understand the principle and process of oxygen cutting, the conditions of metal gas cutting and the application of gas cutting.
② Understand the model and structure of cutting torch, and pay attention to the difference between cutting torch and welding torch.
③ Observe the manual gas cutting of low carbon steel. Observe the preheating temperature of the metal (pay attention to the color of the steel plate, and note that the steel plate has not melted at this time), and then put in the cutting oxygen (pure oxygen) airflow, and the steel plate will immediately form a narrow and uniform incision. Note that the steel plate has not melted yet.
④ Demonstration of cast iron gas cutting. Note: The cast iron has melted during preheating. When the oxygen is turned on for cutting, the airflow only blows away the molten iron, but cannot burn the cast iron below the molten iron. If the thickness of iron castings is small, cracks can be formed, but the cracks are wide and uneven. This means that cast iron cannot be cut by gas.
⑤ Visit semi-automatic gas cutting and write down the model and main technical parameters of semi-automatic gas cutting. Observe the surface quality of incision and notch width.
⑥ Visit profiling gas cutting, photoelectric tracking gas cutting and numerical control gas cutting. Observe the surface quality of notch width and notch number, and record the application examples.
3 submerged arc automatic welding
1 Visit the submerged arc automatic welding equipment, understand the composition of the equipment and the functions of each part, and write down the model and main technical parameters of the submerged arc automatic welding machine.
2. Understand the function and brand of submerged arc welding wire.
Understand the brand and function of flux.
Watch the automatic submerged arc welding of longitudinal seam and circumferential seam. Write down examples, including workpiece name, material (steel grade), quantity, workpiece drawing, welding wire, flux (brand) and welding process (joint type, groove type and size, welding wire diameter, welding current, arc voltage, welding speed and welding level, welding sequence, flux pad, etc. ).
5 Watch welding process equipment, such as tire turnover, lifting platform, telescopic cantilever, etc.
4 Other welding methods
1 visit argon arc welding and carbon dioxide gas shielded welding.
Understand and write down the name, model, main technical parameters, equipment composition and function, brand of welding materials (such as welding wire and tungsten electrode) and welding process parameters (such as welding wire diameter, tungsten electrode diameter, welding current, arc voltage, gas flow, automatic welding and welding speed) of famous parts. Observe the appearance quality of weld after welding. Write down product examples.
Visit resistance welding (spot welding and butt welding)
Understand the name, model, main technical parameters and general structure of the equipment used. Watch spot welding and butt welding operations to understand the process of electrification and pressurization. Observe the external welding quality. Write down product examples.
3 visit brazing
Observe the welding process and pay attention to the fact that the base metal (workpiece) does not melt during brazing. Write down examples of brazing products, brazing filler metals (brazing solder), brazing flux (brazing flux) and heating methods.
Visit the welding production process of typical welding structures (such as boiler drum, pressure vessel and steel frame, etc.). ).
Understand the welding production process and the equipment and process equipment used. Write down the name, model and main performance parameters of welding production process and its typical equipment.
Fourth, safe operation.
1. Electric shock protection
Check whether the welding machine is well grounded before work; Check whether the electrode holder is in good condition. Special attention: welding machine rear connector.
2. Prevent arc burns and scalds
Arc light contains a lot of ultraviolet rays, infrared rays and strong visible light, which is irritating to eyes and skin. Do not touch the welded workpiece. When tapping welding slag, use proper force and pay attention to the direction.
3. Protective equipment
Welding mask, leather gloves, rubber-soled shoes
4. Safety of equipment
Don't put the electrode holder on the European worker or the workbench to avoid short circuit burning the welding machine. If you find a high fever or a burning smell at work, stop working immediately, turn off the power and report to the teacher.
5. Self-prevention and treatment of eye burns
(1) human milk drops
② Eye drops
(3) cold and wet towel eyes.
Although our internship time is very short, we have learned a lot of knowledge that we want to learn, which makes us have a further understanding of the welding industry. During the internship, we studied welding knowledge seriously with the masters and worked hard to cultivate our spirit of hard work. This internship also made me feel the combination of theory and practice for the first time. Generally speaking, I have successfully completed this internship, which will play an important role in my future work.