What is Contact Resistance in Welding?

Contact resistance is the resistance in ohms between the contacts of a relay, switch, or another device when the contacts are touching each other. This can be an important factor in welding, as it can affect the electrical current passing through the weld and potentially cause problems with the weld itself.

Contact resistance can be affected by a number of factors, including the materials used for the contacts, the surface area of the contact, and the pressure between the two surfaces. Welders should be aware of these factors and take them into account when setting up their welding equipment.

How do you increase contact resistance?

There are a few ways to increase contact resistance, including:

Increasing the pressure between the two surfaces.
Decreasing the surface area of the contact.
Using materials with a higher resistivity for the contacts.

Thermal contact resistance

It is a type of contact resistance that occurs when two surfaces are in contact with each other but are not able to conduct heat. This can happen when there is a gap between the two surfaces, or when one of the surfaces is not a good conductor of heat. Thermal contact resistance can be a problem in welding, as it can cause the weld to be cooler than it should be and potentially cause problems with the quality of the weld.

Resistivity

The resistivity of a material is a measure of its ability to resist the flow of electric current. It is measured in ohms per meter (Ω/m). The higher the resistivity of a material, the more resistant it is to the flow of electric current. This property is important in welding, as it can affect the amount of current that flows through the weld and potentially cause problems with the weld itself.

Thermal contact conductance

It is a measure of the ability of two surfaces in contact to conduct heat. It is measured in watts per square meter (W/m2). The higher the thermal conductance of a material, the better it is able to conduct heat. This property is important in welding, as it can affect the amount of heat that is conducted through the weld and potentially cause problems with the quality of the weld.