Stud Arc Welding | Fastener Welding- Advantages and Application

Stud Arc Welding | Fastener Welding- Advantages and Application

Stud welding is a technique similar to flash welding
where a fastener or specially formed nut is welded onto
another metal part, typically a base metal or substrate. The
fastener can take different forms, but typically fall under
threaded, unthreaded or tapped. The bolts may be
automatically fed into the spot welder. Weld nuts generally
have a flange with small nubs that melt to form the weld.
Weld studs are used in stud welding systems.

Stud Arc Welding | Fastener Welding
Stud Arc Welding | Fastener Welding

Stud welding, also known as “drawn arc stud
welding”
, joins a stud and another piece of metal
together by heating both parts with an arc. The stud is
usually joined to a flat plate by using the stud as one of
the electrodes. The polarity used in stud welding depends
on the type of metal being used. Welding aluminum, for
example, would usually require direct-current electrode
positive (DCEP). Welding steel would require direct-current
electrode negative (DCEN).

Stud welding uses a type of flux called a ferrule, a
ceramic ring which concentrates the heat generated,
prevents oxidation and retains the molten metal in the weld
zone. The ferrule is broken off of the fastener after the
weld is completed. This lack of marring on the side
opposite the fastener is what differentiates stud welding
from other fastening processes.

Stud welding is a complete one-step fastening system,
using fasteners called weld studs. Weld studs come in a
variety of designs, threaded, unthreaded, tapped, etc., sizes
and shapes for a wide range of applications.

Stud Welding Equipment

The equipment required for stud welding is composed
of the following:

  • A direct current Power Supply
  • A Controller
  • A Weld Gun
  • Cables to tie the system components and base
    metal together

In most systems, the power supply and controller are
combined as one component called the “Welder”.

A type of stud welding called capacitor-discharge
(CD) stud welding differs from regular stud welding in that
capacitor-discharge welding does not require flux. The weld
time is shorter, enabling the weld to bond with little
oxidation and no need for heat concentration. It also
allows for small-diameter studs to be welded to
thin,lightweight materials. This process uses a
direct-current arc from a capacitor. The weld time in this
process is between 1 and 6 milliseconds. Capacitor
discharge stud welding with the latest equipment can create
a weld without burn through showing on the opposite side of
very thin metals. CD stud welding is often used for smaller
diameter studs and pins, as well as on non-standard
materials and for accuracy. On the other hand, arc stud
welding is primarily for structural purposes and larger
diameter weld studs.

The Stud Welding Process

Stud welding is a process by which a metal stud is
joined to a metal workpiece by heating both parts with an
arc. A key factor that differentiates stud welding from
other fastening processes is that the fastener is
attached to the workpiece without marring the other
side.

 capacitor-discharge (CD) stud welding
 capacitor-discharge (CD) stud welding

The arc stud welding method provides highly
reliable fastening for a wide variety of applications.
This method allows almost any size or configuration of a
metal stud to be welded quickly to a workpiece, while
providing maximum weld penetration and
reliability.

Arc stud welding permits strong, one-sided welds on
base metals with thicknesses starting at 0.048″ (1.2 mm).
It produces welds in as little as 0.06 seconds.

Arc stud welding utilizes a DC power supply to
create the arc, a stud welding tool, metal fasteners, and
in some cases, ferrules. There are three common
techniques of Arc stud welding:

  • Drawn arc stud welding
  • Short arc stud welding
  • Gas arc stud welding

The Benefits of Stud Welding

Stud welding has many advantages over other joining
processes:

  • It is fast. Welding a 3/4” fastener will take
    less than one second.
  • It is single sided. This means that access to
    the other side of the work piece is not
    required.
  • It is secure. Unlike the peripheral weld that
    would be used to weld a bolt in place, a stud weld is
    a full cross sectional weld. This means the full face
    of the fastener is welded in place providing a
    strong, worry-free weld.
  • It is cosmetically superior. As a single sided
    fastener there are no indicators that a fastener is
    attached.
  • It is welded and will not work free like a
    press-in fastener
  • Requires no special skills and little training
    to install.

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