Welding technical skills

1. 1 Work has a direction and a goal.

Do any work with goals and directions. Generally speaking, do you want to be a good welder? If you don't really want to be a "welder", then give up the profession of "welder" and engage in a job that suits you. Then, if you have been engaged in the profession of "welder", you should set a benchmark, set a direction, invest in a "famous teacher" and set a correct direction and goal, so as to achieve success in this profession. When I look back on my life journey, I find that my life has not been wasted and my efforts have not been in vain. We added a "psychological counseling course" in welder training, first preaching the correct outlook on life, and then teaching welding skills, which played a good career-oriented effect.

1.2 cultivate the spirit of hard work and perseverance

"Electric welder" is independent and generally irreplaceable. At present, the degree of welding automation and mechanization in field installation engineering is still low, and welders still rely on manual operation, which is labor intensive. Therefore, to be an excellent welder, we must be prepared to "suffer hardships". If you want to do something well and do it well, you need to work twice as hard as ordinary people, pursue it persistently, and even work dozens of times to make progress and success.

1.3 Willing to study and study.

Often some welders think that they can do a good job as long as they are steady and willing to endure hardships, but they are not. When welding, material properties, welding method characteristics, equipment characteristics, process characteristics, welding defect principle and overcoming, etc. All need the knowledge of welding theory to pave the way. Otherwise, in the welding process, the welder is "either the donkey can't walk or the donkey can't grind", looking around, stumbling, seemingly beautiful weld, but the welder himself can't say clearly how to actually complete the welding, and there are still different degrees of defects in the weld. Therefore, to be a good welder, we should not only have the spirit of hard work, but also be willing to study and research, so that our experience, experience and skills can be continuously improved and become "top masters".

2 Develop good habits

To do any work well, we must have good living habits. Behavior forms habit, habit forms quality, and quality determines fate. Good living habits, correct working methods and a sense of responsibility for work will make you get twice the result with half the effort and succeed in your career.

2. 1 guide to developing good living habits

Living habits and working habits are closely related, and bad habits in life are very easy to bring to work. For example, if you don't trim the edges at ordinary times, you will muddle along if you don't have strict requirements on the appearance quality of the weld during the welding process; Another example is that we are often left behind and sloppy in our lives, which will lead to the mentality of "dealing with things" in the welding process, which will eventually lead to poor welding quality. All these reflect that a good "welder" needs to pay attention to developing good living habits, being clean and tidy, and paying attention to self-cultivation in order to become a qualified welder.

2.2 guide to develop good work habits

Develop good working habits. Subjectively speaking, make use of your professional theoretical knowledge and operating experience to make a preliminary analysis of welding tasks, find out the unfavorable factors that may affect welding quality and efficiency, and find out the solutions, so as to make welding tasks go smoothly and solve difficult problems on the spot. At the same time, form a good habit of recording and analyzing problems and accumulate welding experience for yourself.

From the objective factors, the objective conditions in the work are ever-changing, so as welders, we should actively respond. For example, in cooperation with related types of work, welders should put forward the requirements of equivalent standards for weld groups according to relevant specifications, so as to avoid entanglement and damage to their reputation when repairing welds due to quality reasons. At the same time, in the workplace, sometimes when encountering unfavorable factors such as strong wind and inappropriate scaffolding, we should actively find ways to take preventive and overcoming measures in order to better complete the assigned welding tasks.

3. Have some knowledge of welding theory.

Welding theory comes from practical operation, and the summarized theory guides operation. Only when skill operation is closely combined with theory can we be a good welder. The theoretical knowledge of welding is very rich and extensive. Many welders know too little about welding knowledge in their initial work. Most welders only know a thing or two from some old masters, only master a relatively simple operation technology, and don't know how to solve welding problems. If stainless steel is welded with carbon steel covered electrode, the weld formation will be poor, because the thermal conductivity of stainless steel is poor compared with that of carbon steel, and the molten pool formed by arc is not easy to solidify. With the development of science and technology and the development of materials, processes and methods, it is very necessary for welders to learn and master more theoretical knowledge.

3. 1 Learn to master the knowledge of welding materials.

In the welding process, you will come into contact with many metal materials, and each material has its own characteristics, such as the mechanical properties of metal materials such as strength, plasticity, hardness and toughness. Physical properties of metals include density, melting point, thermal expansion, thermal conductivity, electrical conductivity and magnetism. These are closely related to the welding process. For example, when austenitic stainless steel is welded, its physical characteristics are large thermal expansion coefficient and large deformation; The thermal conductivity is poor and the weld appearance is difficult to control. Therefore, when welding stainless steel, it is necessary to use small line energy, small current and short arc to weld quickly, speed up the cooling rate, make it stay in the sensitized temperature zone for a short time, strictly control the interlayer temperature, prevent intergranular corrosion and reduce welding stress and deformation.

Avoiding welding defects can also be analyzed by combining theoretical knowledge from macro to micro. For example, the welding blowholes in the construction site are theoretically divided into three types: hydrogen blowholes, nitrogen blowholes and CO blowholes. Based on the macroscopic characteristics of three kinds of blowholes, the blowholes in welding parts are identified and distinguished. Combined with the theoretical causes of qualitative blowholes, the field and welding conditions are analyzed to find out the causes and overcome measures, so as to avoid blowholes. Therefore, many on-site welding phenomena can be solved through the research and analysis of theoretical knowledge.

At the same time, the development of welding materials is endless, which requires welders to study hard to become "advanced welders".

3.2 Learn and master the welding "procedures"

Welding "regulations" include welding standards and specifications, welder assessment rules, etc. This is the basis of implementing welding technology. Just as people must abide by laws and regulations in society, the welding technology and methods of each material have been repeatedly studied, experimented and explored by generations. After repeated verification, only the products welded according to this technology can meet the use requirements.

Welding procedure standard is a set of technical regulations in the welding process. Including welding method, pre-welding preparation, welding materials, welding equipment, welding sequence, welding operation, process parameters and post-welding heat treatment. Different welding methods have different welding processes. The welding process is determined according to the material, brand, chemical composition, structural type and welding performance requirements of the weldment. In addition to the work of welders, we should also strengthen the study and mastery of relevant welding codes and standards.

At the same time, international, national, industrial and local governments have issued many relevant welding specifications and standards. As an electric welder, you should always consult and ask. As shown in figure 1.

Figure? 1 welding related specifications and standards

3.3 Welding environment factors

It is the influence of environmental factors, environmental protection, labor protection consciousness and environment on welding process. If we should pay attention to the influence of rainy and humid weather on welding technology and welding defects. There is also the pollution of welding environment and its impact on human safety. The third is the harm of smoke and dust, splash and so on. And the influence of bad habits on people's health.

4 Exercise excellent operation skills

Many welders only know how to finish the work quickly at work, without seeking good operating skills, so that they feel tired after work and gradually improve their skills.

How can I have a good skill operation level? First of all, in addition to certain knowledge of welding theory, we should also know about metal materials, characteristics of molten pool and other related knowledge, pay attention to the shape of molten pool in the welding process, and choose the correct covered electrode conveying method and welding angle in time to complete good welding.

Of course, a good welder should fully understand the functions of various parts of the body, skillfully choose the appropriate welding posture and make good use of the functions of various parts of the body. For example, the swing of covered electrode is controlled by the wrist to ensure the weld width, and the feed speed of covered electrode is controlled by the elbow. All parts of the body are coordinated, the welding posture is comfortable, and the physical consumption is naturally less.

4. 1 fully understand the role of various parts of the body in the welding operation.

During the welding operation, the welder's eyes, elbows, waist, wrists and other parts have corresponding functions, which should be used reasonably during welding. For example, the eyes mainly play an observation role during the welding operation, as shown in Figure 2. It is difficult to observe the change of molten pool from far to near, and it is easy to cause visual error, which leads to the confusion of molten pool, unsightly weld and easy to appear defects. Similarly, the elbow plays a feeding role in welding operation, and the body or waist cannot be used instead of feeding. Wrist plays the role of covered electrode swing, and the width, swing frequency and pattern of weld are all done by wrist, while the swing of covered electrode cannot be done by elbow swing. Therefore, welders should fully understand the functions of various parts of the body. In the construction site, it is often seen that some welders are sent to cover covered electrode with their bodies, and the welders have to stick them all over. This is not only unsightly, easy to burn, but also harmful to people's lumbar and cervical vertebrae. Many welders suffer from lumbar and cervical diseases at a young age because they have not developed a good welding position and posture.

Fig. 2 the role of various parts of the car body in the welding process.

4.2 welder's position and welding posture

As the saying goes, "there is a standing posture when standing, and a sitting posture when sitting." Of course, welders should also have correct standing posture and welding posture when operating. Correct standing posture and welding posture can not only help the welder to complete the welding task with half the effort, but also effectively avoid the welder's scald and protect all joints, lumbar vertebrae and cervical vertebrae from injury.

The correct position generally requires the welder to choose a reasonable position according to the spatial position of the weld. When standing, we should consider the effective functions of various parts of the body, such as the distance between the glasses and the weld, whether it will affect the swing of the wrist and so on.

Welding posture is also important. Correct welding posture means that all parts of the welder give full play during welding, with low physical consumption, good vision and easy operation. This requires welders to abandon the "make do" mentality from subjective and objective factors, take it seriously subjectively, analyze it carefully and try again and again. With the passage of time, the experience of correct welding posture will become more and more abundant, and objectively, the factors that may lead to incorrect welding posture should be actively eliminated. As shown in figure 3.

Good welding posture? b？ Bad welding posture

Figure? 3 welding posture comparison

4.3 Fully understand the principle of molten pool

The welder controls the welding pool according to the process card and reasonable skills, and realizes the welding with beautiful appearance and excellent quality. Welders are required to fully understand the temperature field of molten pool and the principle of arc transition. Generally speaking, the temperature in the center of the molten pool is basically the highest, the molten iron has good fluidity, and the temperature on both sides and the back gradually decreases. The temperature field change of welding pool is shown in Figure 4.

Figure? 4 Schematic diagram of temperature field change of welding pool

According to this principle, it can be analyzed that the arc molten pool is also moving. As shown in Figure 4, 1-2-3-4-N has been moved. Because the arc frequently passes through the center of the molten pool, the heat in the middle of the molten pool is the highest, so the molten iron in the middle is relatively thin. If 1-2-3-4-n moves at a uniform speed, the middle of the weld will protrude, but the two sides will not be full, resulting in excessive residual height of the weld and undercut on both sides. According to this principle, when welding by hand, the welder must avoid the uniform motion of the arc in the weld. Generally, it is required to stop at both sides of the weld and make a quick transition in the middle to balance the heat of the molten pool, so as to control the weld quality and beautiful appearance.

4.4 Principle of weld pool shape

Take a bottle of water as an example, as shown in Figure 5. When the water bottle is vertical, the water in the bottle is horizontal, but when the water bottle is inclined, according to the principle of natural gravity of the earth, the water in the water bottle is horizontal regardless of the spatial position of the water bottle. Then, the water bottle is compared to a weld, and the water inside is compared to a "molten pool", which is composed of "molten iron". This principle should also be followed.

Then this principle is very important in the daily skill operation of welders. Often, when welding, the welder is influenced by the spatial position of the weld, line-of-sight error, welder's position and welding posture, and the end of the welding pool will be uneven and the weld will be unsightly. Through the principle of this phenomenon, the welder can control and improve the welding pool. As shown in fig. 6.

Figure? 5. According to the principle of natural gravity of the earth, the welding pool is kept horizontal at any position.

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Is the molten pool level well controlled? b？ Poor molten pool level control (lower left and upper right)

Figure 6? The role of molten pool level principle in weld formation

5 concluding remarks

Some people just understand skills as being able to do things, operate tools and equipment or conduct experiments, which is not enough. An excellent welder needs to have correct thoughts, develop good habits, master certain welding theoretical knowledge and exercise excellent skills. At the same time, a perfect weld requires the welder to master the characteristics of welding equipment and welding parameters according to the basic welding theory and relevant standards and specifications, and to control the temperature, arc height, arc swing amplitude, arc swing frequency, arc residence time on both sides of the molten pool, molten pool water level and so on. In the welding process, these parameters are ever-changing, not static, and need to be constantly adjusted by the welder according to the situation in order to better complete the welding task. The above are just a few examples of combining welding theory with practice. In the actual operation process, there are still many skills of combining welding theory with practical operation, which need to be excavated and sorted out by the majority of welding skill operators.