BATUKAWA BRIDGE EXTENSION (QUALITY ASSURANCE ENGINEER-ALSON CHIN)

STUD SHEAR CONNECTION

Stud welding involves the same basic principles and metallurgical aspects as any other type of

arc welding procedure — a controlled electric arc is used to melt the end of a stud or electrode

and a portion of the base metal to form a bond. The stud is plunged automatically into the molten

metal and a high quality fusion weld is made where the weld is stronger than the stud itself.

The KKB Engineering is using the Electric Arc welding for then installation of stud. It is the

most common process and is utilized whenever metal is fabricated. The best bond forms when

the base plate is heavy enough to support the full strength of the welded fasteners, but is

sometimes used with lighter gauge materials. Using a stud welding gun, the stud is welded to the

base plate using a ceramic ferrule to hold the molten metal in place until the bond is formed.

This results in a dense, strong weld that will develop the full strength of the fastener and the base

plate. Welding currents range from 250 to 3,000 amps and the weld cycles range from 0.1 to 1.5

seconds, depending upon the diameter of the fastener and the materials being joined.

This project has adopted the 25mm dia. Stud which required approximate 2000 amps welding

current to melt the both based of stud and working place.

Current DC power supply

Stud welding gun

BATUKAWA BRIDGE EXTENSION (QUALITY ASSURANCE ENGINEER-ALSON CHIN)

ARC STUD WELDING METHOD

STEP 1: Stud and ceramic ferrule are placed in gun and pressed against work plate.

STEP 2: The arc is drawn when the trigger is pressed which melts the fluxed end of the stud along with the immediate work area.

STEP 3: The ceramic ferrule shields the arc concentrating the heat, the gun then forces the stud into the molten pool of metal integrating it with the work plate.

STEP 4: The metal solidifies and welder breaks away the ceramic ferrule to expose the weld fillet around the base of the stud.

BATUKAWA BRIDGE EXTENSION (QUALITY ASSURANCE ENGINEER-ALSON CHIN)

DELIVERY OF GIRDERS

The total of 4 nos girders BG-1, BG2, BG-3 and BG-4 delivered to site on 27th

April 2011.

Unloading of girders by 45 tons mobile crane