Is manual welding technology bottom up welding? How to weld?

Hand welding, vertical welding, bottom-up welding. Here's how:

1. When the first welding wave is welded after the arc is initiated, the arc should be increased quickly; When the molten pool is seen to be instantly cooled into a dark red dot, the arc descends to the arc pit again, and the molten droplet is solidified at the weld wave 2 3 that has been formed in front, and then the arc is raised again.

2. In order to make the two steel plates evenly heated, ensure the penetration depth and improve the work efficiency, the inclination angle of the welding rod should be paid attention to. When the thickness of the two steel plates to be welded is equal, the angle between the welding rod and the two steel plates should be equal to the left and right, and the angle between the welding rod and the center line of the weld should change its size according to the difference in plate thickness, and generally should be kept at 60°-80°.

Precautions: 1. The key to vertical welding operation is how to control the molten metal, which requires concentration during welding, paying attention to observing the cooling of the metal, and the welding rod should swing rhythmically according to the cooling of the molten metal.

2. In the process of vertical welding, if the previous molten droplet is not cooled to a certain extent, the welding rod will be lowered too quickly, which will cause the molten metal to flow down; When the electrode descends too slowly, it will cause poor fusion between the droplets. So keep the speed under control.

First of all, learn flat welding and see the molten iron. Vertical welding is the spot welding of the molten iron from the bottom drop by drop, and each drop is two-thirds of the previous drop of molten iron. Personally, I think vertical welding is the best welding, because molten iron is more beautiful and clear.

When welding with electric welding, it can be welded from top to bottom or from bottom to top.

Electric welding does not require the direction of welding, only the specific welding process will be stipulated, therefore, the upper to lower welding can also be welded from the bottom to the top, and often appears in the welding method of vertical welding, in the welding process, the molten pool metal and the molten droplet have a downward tendency due to the action of gravity, and the weldment is separated, so it is easy to produce welding nodules.

Operating procedures for vertical welding:

1. The current used should not be too large, slightly lower than the fillet welding current, and the size of the welding rod should be selected according to the thickness of the weldment.

2. The arc should not be too large when welding, and should be short-arc welding. Welding method, take the zigzag or triangular welding method.

3. If it is multi-layer welding, the first current should be smaller, and the subsequent welding should be cleaned up to reduce slag inclusion or impermeable welding.

4. The swing should be in place and evenly swinged, otherwise the weld is not particularly good-looking, and it is likely to undercut or have a large weld nodule.

Vertical welding operation skills.

The vertical welding operation is more difficult than the flat welding operation, under the action of gravity, the molten droplets formed by the melting of the welding rod and the molten metal in the molten pool should flow downward, which makes the weld forming difficult, and the welding seam forming is not as beautiful as the flat welding.

For example, vertical butt welding with a plate thickness of 5mm and no groove. This welding method uses a smaller diameter electrode, which is suitable for use, and the current is 80-100A (10-15% smaller than flat welding), so that the molten pool is small in volume and condenses quickly, which can prevent the molten liquid metal from flowing down; When welding, a short arc is adopted, usually the arc length is not greater than the diameter of the welding rod, and the welding rod and the weldment form an angle of 60 0 2-80 0 2, so that the thrust effect on the weld pool is generated by the electric solitary blowing force to support the molten iron, and the welding rod is used to melt the metal to transition to the molten pool; The welding rod is in VY motion (that is, the electrode is arced on one side of the groove, and then transported to the other side after melting), and the rod transportation method can be in the form of "double sawtooth" and "continuous sawtooth", swinging left and right upwards until the welding of the whole weld is completed.

Points to note: 1. The three movements of VX, VY and VZ should be coordinated to prevent uneven penetration of the weld.

2. The melting width on both sides should be consistent to prevent unwelded penetration and keep the weld penetration neat.

3. When the molten iron is applied, it is necessary to make VX movement immediately, and it cannot stay or slow down.

4. Adopt repeated arc extinguishing method to finish.

Electric welding is a rough and fine work, and it is still relatively difficult to learn fine, mainly the welding process. When you burn a ton of welding rods, you will feel that you have improved, and you must be serious at all times when operating. When arcing, you can first let the electrode head contact with the workpiece, and then twist it to the side to start the arc.

The current is small, the electrode is damp, and it is easy to stick the electrode. When learning, you can use half a electrode or a shorter one, which is easy to control. If the workpiece is not important, it can be scratched near the weld, and after the arc is started, it can be scratched to the weld and welded normally.

You can also put a piece of scrap iron next to it, arc on it, and after the electrode head is red (not the electrode is red), it will be moved to the weld immediately, and it will be easy to arc on the workpiece. When welding operation, be sure to buckle the welding helmet before arcing. If you fasten the welding cap, you can't see the weld, so you should know the position of the weld.

You can press the electrode head to the weld at once, and you can see the weld after the arc starts, and you can do it naturally after more work. If the arc starts first and then buckles the welding cap, the eyes will be shaken by the arc light for a short time and cannot see anything, which will also affect the eyesight. Electric welding operation is a skilled process, that is, the workpiece and welding rod are melted and then cast together, and it is more important to control defects when casting.

There is a lot to learn about the welding process.

Grasp the angle, stabilize the wrist, and look at the fullness of the weld.

The volume of the molten pool should not be too large and the arc should not be too long.

Back-up welding is one of the most difficult welding positions among the various welding positions. Since the molten pool is inverted under the weldment, the gravity of the molten metal of the electrode prevents the transition of the molten droplet, and the molten pool metal also falls due to its own gravity. The larger the volume of the weld pool and the higher the temperature, the smaller the surface tension of the weld pool, so the back side of the weld is easy to be dented during upward welding, and the front weld is welded, and the weld is difficult to form.

Therefore, the shortest arc length must be maintained during the upward welding, and the molten droplet is transitioned into the molten pool in a very short time by using the arc blowing force, and the molten pool is as small and thin as possible, so as to reduce the fall due to gravity and prevent the appearance of the weld concave and the appearance of the weld nodulum.

When welding with electric welding, it can be welded from top to bottom or from bottom to top.

Electric welding does not require the direction of welding, only the specific welding process will be stipulated, therefore, the upper to lower welding can also be welded from the bottom to the top, and often appears in the welding method of vertical welding, in the welding process, the molten pool metal and the molten droplet have a downward tendency due to the action of gravity, and the weldment is separated, so it is easy to produce welding nodules.

Can vertical welding be welded from top to bottom? Let you have a comprehensive understanding of vertical welding, and read the knowledge.

This is the earth object is affected by gravity, so it is from the bottom up. It is basically one to two millimeters away from the weld.

Key points of operation of vertical welding:

During vertical welding, the liquid metal and the molten pool are easy to separate due to their own weight. However, if the temperature of the molten pool is too high, the liquid metal is easy to flow down and form welding nodules. It is easy to grasp the welding penetration, but the surface is easy to undercut, it is not easy to weld flat, and the weld forming is poor.

According to the characteristics of vertical welding, the angle of the welding rod should be tilted downward by 60°-80°, the arc should be pointed to the center of the weld pool, and the welding current should be small to control the temperature of the weld pool.

The operation of vertical fillet welding and vertical butt has many similarities, such as welding with small diameter electrodes and short arcs, and the operation posture and the method of holding the welding tongs are basically similar. In order to master the operation skills of vertical welding, we should also pay attention to the following links.

Welding current: Under the same conditions as vertical butt welding, the welding current can be slightly larger to ensure penetration.

The position of the electrode: In order to make the two weldments can be heated evenly, ensure the penetration depth and improve the efficiency, the position and inclination angle of the electrode should be noted. If the thickness of the weldment is the same, the angle between the electrode and the weldment should be equal to the left and right, and the angle between the electrode and the center line of the weld should be kept in the range of 70°-90°.

Control of molten metal: The key to vertical fillet welding is how to control the molten pool metal, and the welding rod should swing up and down rhythmically according to the cooling of the molten pool metal. In the welding process, when the first molten pool appears after the arc is initiated, the arc should be raised relatively quickly, when the molten pool is seen to be instantly cooled into a dark red dot, the arc is quickly lowered to the arc pit, and the molten droplet is overlapped with the front molten pool when it falls 2 3, and then the arc is raised again, so that the weld can be established rhythmically.

If the previous molten pool has not cooled to a certain extent, the electrode will be lowered too quickly, which will cause poor fusion between the droplets, and if the droplets fall incorrectly, the welding wave will be disjointed, affecting the beauty of the weld and the welding quality.

Swing of welding rod: according to the requirements of different plate thickness and welding leg size, the appropriate transportation method can be selected, and the linear reciprocating transportation method can be adopted for the weld with small welding leg size; When the size of the welding leg is large, the crescent-shaped, triangular, zigzag and other transportation strip methods can be adopted. In order to avoid defects such as undercuts, in addition to selecting the appropriate current, the electrode should stay on both sides of the weld for a short time so that the molten metal can fill the edges on both sides of the weld.

The width of the welding rod swing should not be greater than the required welding leg size, for example, when the welding leg with a width of 10mm is required, the swing range of the welding rod should be within 8mm.

Welding method when the local gap is too large: when the local gap exceeds the diameter of the welding rod, the method of downward welding can be taken in advance, so that the molten metal fills the excessive gap, and then carries out normal welding, which can improve efficiency and greatly reduce the spatter and arc blowing of the metal. This method also has the effect of reducing deformation by welding thin plates with too large gaps.

A special downward welding rod must be used, and the dissolved droplet is too large and the current is well controlled.