What is a Weld stud?
Weld Stud is basically a fastener, used to fasten 2 plates/surfaces by welding it on surface of one of the plates. In this welding process, the stud itself acts as an electrode and so external electrode is not required.
What are the different types of studs?
Depending upon the method of welding, studs are classified into following types :
• Drawn Arc studs (welded by generation of arc between stud and base metal)
• Capacitor Discharge studs (Welded by discharging current through the stud. The charge is stored in a bank of capacitors)
What are the different applications of weld studs?
I. Automotive – Studs welded on frame for fitting external parts like dashboard, bumper, etc
II. Transformers – Studs are welded on transformer tanks for ease of fastening lids, etc.
III. Boilers – Non-threaded studs are welded on surface of boiler tubes to increase the surface are for heat dissipation.
IV. Construction – Shear connectors, a type of weld stud, is used in construction as reinforcement in RCC
V. Sheet metal fabrication – CD studs are extensively used in fabrication and also in control panels.
What are the advantages of using weld studs?
• High Productivity – Process lasts for fraction of a second only.
• Costly and time consuming operation like drilling, punching, threading, riveting, etc are eliminated.
• Thin plates can be used as base material.
• Strength of joint is higher than base material and stud.
What is the criteria for selection of weld studs?
The type and material of stud is selected depending on following factors :
• Application (heavy/light duty)
• Torque requirement
• Material of base metal
• Thickness of base metal
• Surrounding environmental conditions
What are Ferrules?
Ferrules are ceramic rings, used during welding of drawn arc weld studs. It is mainly used to :
• Confine the molten metal at base of stud
• Provide protection from oxidation
• Protect welder's eyes from bright arc light
• Provide proper path for gases to escape
One ferrule is required for every stud and it is broken after welding.