Welding Electrical Circuit

In order to understand about the polarity in an arc welding circuit, it is first important to understand the construction of the arc welding circuit. This article discusses a few terms used in any electrical circuit such as EMF, current, and resistance. The later part of the article equates the welding electrical circuit to ordinary … Read more

AC Welding

This article discusses a few aspects related to welding with alternating current, that is – AC welding. The article begins with an introduction to alternating current, followed by features of arc welding with alternating current. Features of Alternating Current Alternating current, as the name suggests, alternates between a positive value and negative value, according to … Read more

Welding: Edge Joint

The edge welding joint is used to join parts that are parallel to each other, or nearly parallel, as can be seen in the figure 1 below. The strength of this joint is not as much as other  types of welding joints, such as butt joint. This joint is commonly used to join edges of … Read more

Welding: Butt Joints

In welding, butt joints are used to join the edges of two plates or surfaces located in approximately the same plane. Butt joint is the most commonly used in the industry among all joint types. The following figure shows plain square butt joints of various thicknesses. As can be seen, there is no beveling of the two parts in … Read more

Surface Hardening of Steel

When an application requires a hard surface, it is not necessary that the entire body of the part be made up of a hard material. That would be uneconomical. A better way is to achieve hardening of the surface alone, while the base metal underneath continues to be plain carbon steel. This is called surface … Read more

Welding: Lap Joint

There are mainly five types of joints in welding: edge joint, corner joint, butt joint, tee joint, and lap joint. This article discusses the ways in which a lap joint can be made. See the figure below. As the name suggests, lap joint refers to a joint when two parts β€˜lap’ with each other, as … Read more

Welding Over Paint

Welding over paint is not a straightforward matter as it might seem. Paints are made of complex chemical substances that vaporize upon coming in intense heat of the welding or cutting arc. These chemical vapors can be harmful to the health of personnel. Hence, welding directly over paint is generally discouraged. Most codes and standards … Read more

Arc Welding With Constant Voltage

In welding β€“ besides the current current power source, the second type of power source is the constant voltage (CV) machine or the constant potential (CP) machine. It has a relatively flat volt-ampere characteristic curve. In this article we shall discuss about arc welding with constant voltage. Features Of A Constant Voltage Machine The figure below shows … Read more

Arc Welding With Constant Current

The power source is the most important part of the arc welding equipment. In all arc welding processes, two kinds of power sources are generally used, from a voltage-ampere output characteristics point of view.    One is constant current type, the second is constant voltage type. This article details the constant current type power sources in … Read more

Other Arc Welding Equipment

This article discusses the auxiliary items (besides the power source) that enable a safe, quality welding. Besides the power source, other arc welding equipment includes welding cables, electrode holders, welding tables, clamps, backup bars, helmets, goggles, and accessories. This article briefly touches upon these. Cables Two welding cables are used in all arc welding machines. … Read more