Welding Basics: How to Learn How to Weld Metal | Types of electric welding

The Welding Basics are a fabrication process that joins two or more pieces of metal or thermoplastics by heating the surfaces to their melting point and then applying pressure to fuse them together. It is a skill that is used in a wide range of industries, including construction, manufacturing, automotive, and aerospace. If you're interested in learning how to weld, it can be a bit overwhelming to know where to start.

Whether you're looking to develop a new hobby, start a new career, or tackle a DIY project, this article will provide a comprehensive guide on the basics of welding and how to get started.

We will cover the different types of welding, the equipment you'll need, and the best practices for learning and honing your welding skills.

Welding Basics

The essence of electric welding of metal is as follows. The power unit in the form of a transformer or inverter generates a certain current, which is fed through cables to a special metal electrode. An electric discharge occurs between the metal workpiece prepared for welding and the electrode, forming a stable high-temperature electric arc that melts the metal. In this case, a point bath of boiling metal is formed in which the electrode itself melts, which simultaneously plays the role of filler material.

The welder moving the arc forms a seam where the boiling metal of the two workpieces welded together mixes to form a single monolithic joint.

Types of electric welding

An electric arc burns due to the powerful current supplied to the electrode. The current can be alternating and generated by a welding transformer or direct, supplied to the welding place by the inverter:

• Transformer. Depending on the model, it can be connected to a network of 220 or 380 V. But a beginner will find it difficult to work with this device, because with alternating current the electric arc is unstable and it is quite difficult for a person who has little experience in welding, to hold her. In this case, the arc creates noise and it is typical to spray boiling metal from the bath. The transformer itself is very heavy, and bulky and creates significant voltage drops in the electrical network, especially at the moment of ignition of the electric arc. This, of course, negatively affects household appliances.
• Inverter. It gives direct current to the electrode, converted from the alternating current that it receives from a centralized electrical network with a voltage of 220 V. The device is light, compact, works silently and practically does not affect the voltage in the network and is characterized by high performance. The direct current applied to the electrode provides a stable arc burn that can even be used to cook tin, making it easier to control and move during welding.

This is such a device that a novice craftsman should use to acquire welding skills.

Process technology

Electric welding refers to the process of melting metals at high temperatures. In order for it to be clear how to properly weld metal by electric welding, you need to be aware of all the processes that take place:

1. The electric arc is ignited when the electrode touches the metal, after which a small distance (2-5 mm) is formed between them, which must be maintained constantly. Under the influence of the arc, the metal of the welded parts and electrode is melted and mixed.
2. The volume of the weld bath depends on the voltage applied to the electrode, its position in space, the speed with which the electric arc moves, the size and shape of the edges of the welded parts and other aspects. The average depth of the bath is usually about 6 mm, the length about 10-30 mm and the width 8-15 mm.
3. The coating of the electrode during combustion forms a cloud of gas that protects the arc and the molten metal from oxidation when interacting with air and also provides support for a certain temperature necessary for melting the metal.
4. At the moment when the burning electrode moves from the point where the metal has just been melted, the process of crystallization and cooling of the seam, connecting the welded parts, begins. At the same time, a slag crust forms on its surface, which is subsequently knocked down with a hammer.
5. The slag formed on the surface of the molten metal from the coating of the electrode is also able to maintain the temperature during the crystallization of the metal, preventing oxygen from the air from getting into it.

Welding tools

Welding inverters are now sold with a cable set with an electrode holder and table attachment. But when buying all these items for work, it is recommended that you carefully inspect them to be sure of their quality.

Welding cables must be covered with flexible rubber insulation with reliable brass contact bushings and fit into the connector of the selected machine. If the inverter is designed to operate within 150A, its cable should have a cross-section of about 16 mm 2. At a current strength of 200A - 25 mm 2 and above 250A - it is desirable to use a cross-section of 35 mm 2. It is also undesirable to lengthen the wires, as this reduces the power of the current supplied to the electrode.

[caption id="attachment_242" align="aligncenter" width="300"] Welding surface[/caption]

Electrode holder It is the most important tool of the welder because it performs the main manipulation of the electric arc when welding metal. Usually, this is a qualitatively insulated and completely safe holder in the form of clothespins. This model is convenient in that after replacement, before cooking with an electrode, it can be set not only perpendicular to the holder but also set to a certain degree of 45 °.

The clamp with which the table is connected to the workpiece to be welded must have powerful springs and brass contacts.

In addition to all this, the welder must be equipped with:

1. A protective mask that prevents the harmful rays of the welding arc from passing through.
2. Gloves and clothing made of dense, fire-resistant materials and leather shoes.
3. Auxiliary tools in the form of a combined hammer with a chisel and a metal brush.
4. A bucket of water or a fire extinguisher.

Electrodes are selected depending on the thickness of the metal to be welded. The power of the welding voltage is set based on the diameter of the electrode used, while it should be based on the value - 1 mm diameter of the electrode has enough power in the range of 30-40 A.

It is recommended not to exceed this value, otherwise, the electrode, instead of quietly melting the metal, will simply blow it out of the bath.

The basics of the electric arc method

In the recommendations on how to learn how to cook with an inverter, it is recommended to pay attention to the beginning of the welding process. Before starting work, it is necessary to weld the parts in a predetermined position and, if necessary, fix them securely on the work surface. For fire safety, there should be a bucket of water nearby. To prevent accidental fire, do not weld on a wooden base. It is not allowed to scatter hot ignition electrodes in the welding area.

Electric arc ignition and stitching

To ignite the arc without gluing the electrode, it is recommended to tilt it to the metal part at an angle of about 60 ° and make a sliding movement with it (roughly, like a boxing match). After the spark appears, the electrode should be torn from the metal at a distance of no more than 3-5 mm and keep it in this position throughout the welding process. If the electrode sticks to the surface of the metal during the ignition of the arc, you just need to turn it to the side and repeat the ignition attempt.

[caption id="attachment_240" align="aligncenter" width="300"] Welding Basics[/caption]

To ignite the arc without gluing the electrode, it is recommended to tilt it to the metal part at an angle of about 60 ° and make a sliding movement with it (roughly, like a boxing match). After the spark appears, the electrode should be torn from the metal at a distance of no more than 3-5 mm and keep it in this position throughout the welding process. If the electrode sticks to the surface of the metal during the ignition of the arc, you just need to turn it to the side and repeat the ignition attempt.

The electrode during arc burning should move slowly along the welded edges of the metal parts, smoothly making them oscillatory movements. With these movements, the metal, melted at high temperature, is "inserted" into the center of the bath, forming a monolithic, slightly convex seam.

After burning the electrode to the minimum size, it must be replaced with a new one. After that, the slag is removed from the welded seam, and then at a distance of about 10-12 mm from the depression that has formed at the end of the weld, the electric arc is ignited.

The electrode is then returned to the recess, filled with boiling metal from the electrode, and the work continues.

Manipulation of electrodes

Before learning how to cook with an inverter, you need to familiarize yourself with the trajectories of the electrode, which must be done during welding. They can be done in three directions:

1. Progressive movement. Small oscillating movements of the arc are made during the weld. To do this, it is enough to maintain a stable burning of an electric arc of a certain length.
2. The criss-cross movements from the side are made to form a specified width of the weld. It is usually used to overlap previously applied welds.
3. Longitudinal direction. A simple but thin seam with a certain height is formed, which is formed depending on the speed of the electrode and its diameter. To give the resulting weld greater strength, it is overlapped with a new one made with the help of the transverse movement of the electric arc.

In practice, when welding particularly thick metal, all three movements are used, which are carried out in turn with successive overlapping of the next seams on top of each other.

In addition to classic manipulations, each welder develops a personal style over time. But the main work is to melt the edges of the welded parts well and create a seam of a certain height and width.

Weld Work with pipes

Manual arc welding can be applied to vertical, horizontal and ceiling seams, and the simplest is welding in the lower position. For example, heating, with a horizontal position of the pipeline, and welding is carried out in almost all spatial positions. Also, if the pipe is vertical, only a horizontal seam is applied.

[caption id="attachment_241" align="aligncenter" width="224"] Welding Pipes[/caption]

The pipe can be independently welded by rotating it around its axis using a gas apparatus or an inverter. In this case, it is welded with a vertical seam or in the lower position.

If the wall thickness of the welded pipes is not more than 6 mm, two seams are applied to the joint: the root and an overlapping layer. With a wall thickness in the range of 6-12 mm, at least 3 layers are applied. If the metal has a thickness greater than 19 mm, then the seam is formed by four or more layers.

Each sewn seam must be freed from slag and thoroughly cleaned, after which it is allowed to apply another layer.

The most responsible seam is the first (root). It completely melts the ends of the pipe and after welding is carefully checked for pores and cracks. If they are found, they are cut out and that place is boiled in a new way.

The second layer and all subsequent ones are performed at a slower pace, while the beginning of each new layer should come from the previous one with an offset of 15-30 mm. The final top layer should smoothly blend with the metal surface of the pipe being welded and have a defined leg.

To improve the quality of the welded pipe connection, a new layer in connection with the previous one is carried out in the opposite direction.

A few tips from us

To better learn the practical lessons of electric welding, it is recommended to start training with the ability to sew on a thick metal sheet. It is easier to learn how to manipulate an electric arc on it, imposing various stitches using simple measured movements of the electrode. The acquired skills will help you feel at what angle of the electrode and with what movements the seam is better and in the future will help you develop a certain style of holding the holder.

It is not recommended to immediately weld two parts with a long continuous seam. With temperature, the seam will shrink and the welded part will deform. To prevent this from happening, the parts should be temporarily fixed together with small point feet with steps of about 80 - 250 mm. The step depends on the size of the workpieces prepared for welding.

Conclusion

In conclusion, welding is a valuable skill that is used in a wide range of industries. Learning how to weld can open up many opportunities for career development, DIY projects, and personal growth.

Understanding the basics of welding, including the different types of welding, the equipment required, and best practices, is the key to getting started. It's important to start with simple projects, practice consistently, and seek guidance from experienced welders.

Keep in mind that welding requires a lot of patience, focus and attention to detail, but with dedication and determination, you can achieve great results.