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Stud Welding
With over 20 years experience in stud welding operations, FASTEN is undoubtedly Singapore’s leading stud welding expert.
We are the market leader for the supply of Shear Studs/ Shear Connectors and the Rental of Stud Welding Machines in Singapore, and had experience working with multiple LTA projects.
Fasten Enterprises provide on-site and work services for the fixing of shear connectors, including thru-deck stud welding. Currently, our sales network is supplying more than 3 million studs per year across different projects and applications.
We also provide rental services of Stud Welding Machines to project sites and steelyards. Our NELSON Stud Welding Machines are at the top of its class in stud welding and where site space is limited, we can also supply inverter units, if required.
Welding thru-deck is a common practice in the composite slab design. The shear connectors (or shear studs) are welded by the drawn arc stud welding machine. As stated in the ISO 13918 standard, there are two types of ceramic ferrules, one for direct welding (directly welding on the beam), and the other for thru-deck welding. No holes are required on the metal deck and there is no need to clean or finish the metal deck after the process.
Stud welding is an extremely quick fastening technique. To use stud welding on a large scale, users can speed up the process by using a heavy-duty NELSON Stud Welding Machine. With the training provided by the Fasten Technical Team, your workers can create up to eight stud welds per minute.
When it comes to your power source, consult our Fasten Technical Department for the recommended fusing, primary wire size, and primary wire length for the power source to be used. Inadequate primary power or incorrect wire size or length can contribute to a reduction in weld current when some rectifier-type power sources are used. Inadequate power or fusing can also hamper the starting and output current for the generator.
It is essential to have the correct weld current and weld time to achieve a good weld. When excessive cable lengths are used, our Fasten Technical Team will look into the reduction in weld currents and adjust the settings accordingly for our users. Without technical support, these factors may contribute to weld inconsistency or even weld failure. The amount of cable totally depends upon the power source being used. Our technical department will advise if there is a need for a parallel cable when long runs are needed.
Stud welding is popular partly because of how quickly it can be carried out. Compared with processes such as drilling and tapping, it is fast and simple. The most common method is to heat the parts to be joined briefly but intensively utilizing an arc. This melts the surfaces to be joined. The bolt or stud is then pressed into position with a special welding gun. Steel bolts or studs up to about 25 mm diameter can be welded in this way. The process may also be used for stainless steel, copper, and brass items. Aluminium can be welded using the capacitor discharge method. Stud welding can also be easily mechanized, e.g. for robot welding.
With the right equipment and stud materials, workers can turn out a stud weld in milliseconds. The speed, however, does not affect the strength and reliability of the resulting joints. They are stronger than the parent material itself once formed and will last a lifetime.
Here are Some of Stud Welding Benefits:
Appearance.
Stud welding is favored for the largely “invisible” effect it creates due to the fastening process only being carried out on one side of the parent material. It leaves minimal marks on the reverse side. Although stud welding is recommended for its ‘invisible’ appearance, it is still equally and more secure than other forms of fastening methods.
Adaptable.
Stud welding can be used with a variety of metals and stud sizes. Stainless steel, mild steel, aluminum, copper, and brass can be effectively stud welded if the proper equipment is used. The studs can be threaded, unthreaded, or internally threaded, and range in diameter from 1 to 25 mm, if you have the correct attachments and equipment to go with them.
Accessible.
With stud welding, workers do not have to contort themselves to make an effective weld. They only need access to a single side. And there is also equipment to make maneuvering even easier. For example, thinner welding tools let welders work in hard-to-reach areas.
No holes.
No holes are made in the metal sheet when the stud is fused to it, so there is no need to clean or finish the metal sheet after the process. The risk of there being any leaking or weakening of the sheet is therefore eliminated. No leaking also prevents the weld from corroding, so it remains clean and durable.
Speed.
Stud welding is an extremely quick fastening technique. To use stud welding on a large scale, users can speed up the process by investing in heavier-duty equipment. There are stud welding machines, for example, that can create up to eight stud welds per minute. The process can also be completely or partially automated to create up to 60 stud welds per minute.
Types of Stud Welding
Three major types of stud welding are equally as effective. Deciding which to use depends on weld requirements, materials, and applications.
Capacitor-Discharge (CD) welding is a common stud welding process recommended for instances where weld joints must be practically flawless and reverse marking needs to be kept to an absolute minimum for appearance’s sake. It is highly effective on clean and flat parent materials such as mild steel, stainless steel, and aluminium.
CD welding works with materials at least 0.7 mm thick, so it is the best option for thin parent materials. CD is more restrictive than the other processes in terms of the diameter of the stud that can be welded. Smaller-diameter studs (1 mm) are required for effective and reliable welds.
CD is not as versatile as the other types of stud welding. Therefore, if your parent material is dirty, coated, or bent, the better choice might be Drawn Arc (DA) welding.
Despite CD welding not being as tolerant to imperfections on parent material as other welding types, it is inexpensive and fast (hence its popularity).
CD welding involves capacitors set to certain pre-set voltages depending on the stud diameter and parent thickness. The stud is placed so that the weld pip, a small bit of metal on the bottom of CD studs, touches the parent materials. That way, an electrical current discharged through the metal sheet and stud heats both to their melting points and forms a molten pool. Spring in the welding gun then pushes the stud into the melted surface area of the parent material to fuse the two parts.
To make long-lasting stud welds, the CD equipment needed is lightweight, easy to use, and will not take up much space.
There are several factors to keep in mind when choosing CD gear, including how light the welder is, how hard is it to use, the recharge time for the equipment, the welding speed, and its flexibility. Different factors may be more of a priority when choosing CD equipment depending on the anticipated tasks.
Drawn Arc (DA) welding is far more versatile and adaptable in terms of the materials and diameters that can be welded. For example, if you are working with a thicker parent material (> 2 mm) and it is rusted or coated, DA is the stud welding method that works effectively and accurately with thicker or less-pristine metals, also in weld through deck application.
Similarly, if requirements involve a stud weld of a larger diameter, this is most likely the one that should be used.
For DA welding, the current and weld times are pre-set according to the diameters being welded. Placing the stud onto a plate or metal sheet triggers a pilot arc of electricity. The stud is lifted to a pre-set height to create the main arc which causes the stud’s pointed weld end to melt into a molten pool. Return pressure on the weld gun pushes the stud into the pool to fuse the stud and metal sheet. A ferrule holds the stud in place and shapes the weld, but is chipped away once the weld is complete.
There is a range of welding machines and products to choose from for DA welding, including some that handle studs larger than 25 mm in diameter or larger. The proper equipment for any application depends on how accessible and maneuverable the welder must be, the current needed, the base stud diameter, and the required welding rate.
Short cycle welding (SC) is practically the same as DA but even faster. Studs can be welded to a parent material in 10 to 100 milliseconds.
SC welding uses a combination of the CD and DA processes, so it can be used with thicker and more imperfect materials than CD, but not as thick materials and studs as DA can tolerate. SC welding may be suitable for those with smaller budgets, as the equipment and tools are less expensive than those used for DA.
The SC process, like DA, requires a weld time and current to be pre-set according to the stud diameter. Similar to CD, the studs have a weld pip, which is placed on the parent material, causing a pilot arc of electricity. Once the stud is lifted to the pre-set height, the main arc melts the surface of the metal sheet and weld pip to create a molten pool. As with the other processes, return pressure pushes the stud and sheet together to form the secure fastening.
Stud welding clearly has a range of benefits and functions. However, it is important to use high-quality equipment from a reputable source to ensure stud welding is efficient and the results are reliable. Fasten Enterprises provides a reliable fixing system with high-quality anchor materials complied with ETA European Design Code and Material Specification Standard along with reliable and well-proven technical support and services.
