Top welders rely on technology to make a living. They are good at work and have good skills. You must come to solve problems at critical moments. Projects cannot be carried out without you. Bosses are scrambling to hire such welders. They are popular everywhere, and their salaries cannot be calculated on a daily basis.
Ordinary welders have average skills, average abilities, average ideas, and average creativity. They work honestly and regularly, and earn hard-earned money and technical money, with occasional highlights.
The worst welders are those who earn hard-earned money and physical money. They have no experience and no skills. They can only be a “tailor” who sews and mends. They can’t even swing a welding gun. To put it bluntly, their skills can’t hold people.
“Water flows to low places, and people go to high places.” The pursuit of excellence is not only a manifestation of the spirit of craftsmanship, but also can increase income, promotion and salary increase, realize personal value, and become a great person in the eyes of others. As a welder, you have to quietly learn these three skills in welding technology, and then you can surprise people around you and make them look at you with new eyes.
1. Single-sided welding and double-sided forming technology
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Single-sided welding and double-sided forming technology is a difficult operation technology for welding rods and arcs. Only by mastering the essentials and skills of operation can the welds and test pieces with qualified internal and external quality be welded.
Single-sided welding and double-sided forming operation technology uses ordinary welding rods and special operation methods to weld on the front side of the groove without any auxiliary facilities on the back side of the groove. After welding, it is a welding operation method that ensures that both the front and back sides of the groove can be uniform, well-formed, and meet the requirements of the weld.
It is a difficult operation technology in welding rod arc welding, suitable for important welds that cannot remove the weld root from the back and re-weld.
Manual single-sided welding is generally divided into two types: continuous arc method and broken arc method. The continuous arc welding arc burns uninterruptedly, and has the characteristics of high production efficiency and good quality.
If the operation process performance of the welding rod is improved, the continuous arc welding method only requires the operator to maintain a stable and uniform rod movement, and its technique does not change much and is easy to master.
The broken arc method relies on the length of time when the arc starts and extinguishes to control the temperature of the molten pool. Therefore, the selection range of welding process parameters is wide and easy to master, but the production efficiency is low and the welding quality is not as good as the continuous arc method.
2. Fish scale welding technology
1. Fish scale welding skills
TIG welding itself belongs to open arc operation, which can well observe the shape and flow of the molten pool, which is much better than arc welding.
Controlling the stability of the hand during welding is the biggest key to avoid shaking and burning the dock electrode, causing tungsten to be clamped in the molten pool.
The control method can be supported by the index finger holding the welding gun on the welded pipe or plate.
The extension length of the tungsten electrode can be selected according to the depth of the groove, generally 3-5MM.
Regarding the wire feeding method, it can be selected according to the size of the groove. When the groove angle is small, the welding wire can be placed in the middle of the molten pool and fed continuously.
When the groove is large, the wire can be fed from both sides (it must be quite skilled to avoid touching the tungsten electrode), and the welding gun moves left and right to make the edges fuse well.
Regarding the full fish scale pattern on the surface, according to the scoring standards of the test competition, the TIG weld excess height is generally 0-2MM, and the surface is smooth without undercut, pores, cracks, and unfused.
The general methods of electrode swinging for flat butt welding are zigzag, crescent, triangle, ring, and figure eight!
The key to vertical fillet welding is how to control the molten pool metal. The electrode should swing up and down rhythmically according to the cooling condition of the molten pool metal.
During the welding process, when the first molten pool appears after the arc is struck, the arc should be raised quickly.
When the molten pool is seen to cool into a dark red dot instantly, the arc is lowered to the arc pit, and the droplet is overlapped with the previous molten pool by 2/3 when falling, and then the arc is raised.
In this way, the vertical fillet weld is formed rhythmically.
The quality can be seen from the welding fish scale pattern: the coarse and uneven welding pattern is obviously the uneven appearance of the weld, and the swing arc is unstable during the welding process. The smaller the weld appearance pattern, the more stable the swing arc is during the welding process.
2. Influencing factors
1. Argon flow rate In order to reliably protect the welding area from air pollution, there must be enough protective gas. When the flow rate is appropriate, the molten pool is stable, the surface is bright and free of slag, there is no oxidation mark, and the welding tongs are beautifully formed;
If the flow rate is not appropriate, there will be slag on the surface of the molten pool, and the surface of the weld will be black or have oxide scale. The appropriate flow rate of argon gas is 0.8~1.2 times the nozzle diameter. Empirical formula Q=(0.8~1.2)D
2. Nozzle diameter The size of the nozzle diameter directly affects the range of the protection area. It is generally selected according to the tungsten electrode diameter. According to production experience: 2 times the tungsten electrode diameter plus 4mm is the selected nozzle diameter. Empirical formula D=(2.5~3.5)d
3. The distance from the nozzle to the weldment Here refers to the distance between the nozzle section and the weldment. If the distance is too large, the gas protection effect is poor: if the distance is too small, although it is beneficial to gas protection, the range that can be observed and the protection area become smaller. The distance between the nozzle and the weldment should be 5~14mm.
4. Tungsten electrode extension length To prevent arcing
3. Overhead welding technology
Overhead welding is the most difficult of the four welding positions. Because people are in an unnatural position during overhead welding, it is difficult to operate stably. At the same time, the operator has to lift the heavy welding gun and cable, which increases the difficulty of operation.
In addition, the molten iron in the molten pool is easy to sag during overhead welding, which is easy to form a convex weld bead, and in severe cases, it causes the iron liquid to flow. Therefore, the welding parameters should be strictly controlled to obtain a good weld formation.
1. Single-pass overhead welding
Thin plates often use single-sided welding. In order to be able to penetrate, the workpiece should leave a gap of 1.4~1.6mm.
Use fine welding wire (diameter 0.8~1.2mm) for short-circuit transition welding, the welding current is 120~130A, and the arc voltage is 18~19V.
At this time, the molten pool should be maintained by the arc force and surface tension in a straight line or small swing. When the welding speed is too slow, the molten metal sags, the weld surface becomes uneven, and in severe cases, the molten metal is lost.
Therefore, you should always pay attention to the state of the molten pool during welding, and adjust the welding speed and swing mode in time. When the welding gun is tilted too much, it will cause convex welds and undercuts.
2. Multi-layer overhead welding
When the workpiece is thicker, multi-layer welding is required. When there is no backing plate, the first layer of weld is similar to single-sided welding. When there is a backing plate, there should be a certain gap between the workpieces, and the current can be slightly larger, but it is still a short-circuit transition.
At this time, the welding current is 130~140A, and the arc voltage is 19~20V.
During operation, the welding gun should be aimed at the center of the groove, the welding gun should maintain the corresponding angle, and move at a constant speed with the right welding method.
At this time, it must be noted that the backing plate and the root of the groove should be fully melted, and no convex weld should appear. For this reason, a small swing should be used, and a little stay on both sides of the weld to obtain a weld with a flat surface, creating good conditions for the subsequent filling weld.
The second and third welds are welded in the form of uniform swinging welding gun, but a short stop should be made at the junction of the previous place and the groove surface to ensure full penetration and prevent undercut.
The welding parameters used at this time are welding current 120~130A and arc voltage 18~19V.
After the fourth layer, due to the large width of the weld, it is easy to produce incomplete penetration and pores when the swing amplitude is too large.
Therefore, it is best to adopt the deposition method, that is, from the fourth layer onwards, two welds are welded for each layer.
In these two welds, the first weld should not be too wide, otherwise it will cause the weld to sag and the groove left for the second weld to be too narrow, which will easily cause the second weld to form incomplete penetration and convex welds. Therefore, the first weld passes the center slightly, and the second weld should overlap the first weld.
The cover weld is a decorative weld and should be beautiful.
First, ensure that the surface of the previous weld of the cap weld is flat, and make the weld about 1~2mm away from the workpiece surface.
The cap weld is also completed with two welds; when welding these two welds, the arc groove should be slightly stopped on both sides to prevent undercut and insufficient excess height. When welding the second weld, pay attention to evenly overlap with the first weld to prevent irregular height and width of the weld.
The welding parameters used at this time are relatively small, the welding current is 120~130A, and the arc voltage is 18~19V.
Summary
Today, we introduced three advanced welding techniques, which can be called the “Nine Yin Manual” in welding. After practicing, the internal strength will be greatly increased, and it will be in the welding world.
Any unique skill is not easy to practice, and it must pay physical and mental strength. It depends on your determination to test a person’s willpower and endurance, as well as the loneliness that must be endured to become a master.
Post time: Nov-25-2024
