Nut Spot Welding Basics

Posted on May 25, 2021

Nut Spot Welding

Nut spot welding is a process where nuts or fasteners are joined onto metal parts. To practice spot welding, electrodes with pointed tips are used as the welding tool to create opposing forces that allow metal parts to be heated and joined. The shape of the electrode may differ based on the current, heat generation and weld nugget size, etc.

Nut welding refers to the projection welding process used to weld threaded nuts onto a metal object. A nut welding is a projection weld because the nut usually has a partial or full ring projection or the corner edges of the nut are formed into projections. Spot welding on the other hand refers to the welding process that joins sheet metal products. A nut spot welding is the welding process in which a nut is attached to a sheet metal applying the spot welding technique.

Nut spot welding is a common form of welding in the appliance and automotive industry where the nuts are needed for the assembly of parts on an object. The nuts provide assembly points for screws, bolts, and other fastening accessories used in part assembly. Nut spot welding is one of the major welding approaches applied for creating nut weld. In a nut welding process, spot welding, as well as other forms of resistance welding, can be used. Also, based on the end application, specially made weld nuts may be used in some welding processes.

Resistance Welding

Spot welding is a type of resistance welding that is often used for nut welding or fastener welding processes. Resistance welding is a cost-effective welding process because no additional medium materials are required to forge the two parts together. Though resistance welding has its cost-effective nature, it does not indicate that this particular welding technique is less reliable than other welding processes. The welding method should be chosen based on the end application after all. Different types of resistance welding apply the same working principle to form welds on the welding points.

The resistance welding applies pressure and electrical current onto the welding point for a length of time. The weld is made by conducting a strong current through the metal combination to heat up and melt the metals at the localized point. During resistance welding, the pressure is always applied so that the current is confined to the contact area of the two metal parts. The resistance refers to the electrical resistance of metals. When the current passes through the metal, the resistance causes the metal to heat up and melt eventually.

Fastener Welding

Resistance welding is the most common method used for fastener welding. The three factors that affect the welding results the most are heat, time, and pressure. Heat is generated by the electric current released from an electrode. For joining smaller fasteners, less heat is required; as for joining larger fasteners, more current will be released to create stronger welds. On the other hand, the pressure setting varies based on the material of the fastener and the base metal. For low-carbon material, lower pressure is applied; for stainless steel, higher pressure is required. The welding time refers to squeeze time, weld time, and hold time. If the time is not long enough, the welds may be easier to break when forces are applied to them.

Spot Welding

Spot welding is the type of resistance welding used primarily for joining metal sheets. The process is carried out by a spot welding machine. Nut spot welding is one of its applications where fastening nuts are joined onto metal parts. To practice spot welding, electrodes with pointed tips are used as the welding tool to create opposing forces that allow metal parts to be heated and joined. The shape of the electrode may differ based on the current, heat generation and weld nugget size, etc.

Applications & Benefits of Spot Welding

Spot welding is able to create strong bonds between components; therefore, this method is used extensively in the automotive industry. It is used to join the body of an automobile with other larger components. It is also used in the construction of household furniture and other appliances. Domestic appliances and equipment are often assembled using spot welding. Any piece of equipment made from aluminum and carbon can be spot welded.

Spot welding comes in with a number of advantages. To begin with, the affordability of spot welding is the primary reason why it is favored by manufacturers. Since the working principle of spot welding is not complex, it offers excellent speed and efficiency to the process. The simplicity of it also makes it easy to be incorporated with automatic processes. In addition, spot welding is capable of handling metal sheets that are as thin as 0.25".

Projection Welding

Projection welding is another type of resistance welding. Just like other forms of resistance welding, projection welding relies on heat generated by an electric current to join metal pieces together. Besides the nut spot welding, projection welding is frequently utilized when it comes to the welding for fasteners. Comparing to spot welding, projection welding electrodes are able to apply more current onto the metal parts and hence create thicker welds.

During a projection welding process, two flat electrodes are used to cover the face of a fastener. The projections on the fastener absorb and disperse heat so that strong welds can be formed. Besides the projections, the contact between the nut's projections and the base metal also helps prevent the generation of excessive heat and electrode pressure.

:: Read More: An Introduction to Projection Weld Stud

Applications & Benefits of Projection Welding

Projection welding has a significantly better heat balance compared to other types of resistance welding and it is ideal for joining thick pieces of metal together as a result. Since projection welding is able to create even stronger binds between components, it is applied primarily in the electrical, automotive, and construction industries. These are the applications where nut welding, as well as other forms of fastener welding, is required to provide assembly points for parts.

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