Building Construction Handbook, Eighth Edition

Welding is used to prefabricate the sub-assembly of steel frame

components in the workshop, prior to delivery to site where the

convenience of bolted joints will be preferred.

Oxygen and acetylene (oxy-acetylene) gas welding equipment may

be used to fuse together light steel sections, but otherwise it is

limited to cutting profiles of the type shown on page 535. The

electric arc process is preferred as it is more effective and

efficient. This technique applies an expendable steel electrode to

fuse parts together by high amperage current. The current

potential and electrode size can be easily changed to suit the

thickness of metal.

Overlapping of sections permits the convenience of fillet welds, but

if the overlap is obstructive or continuity and direct transfer of

loads is necessary, a butt weld will be specified. To ensure

adequate weld penetration with a butt weld, the edges of the

parent metal should be ground to produce an edge chamfer. For

very large sections, both sides of the material should be chamfered

to allow for double welds.

BUTT WELD

single V weld

chamfered edge throat thickness T

T

penetration

parent metal

Note: For greater thicknesses of parent metal, both sides are chamfered in

preparation for a double weld.

FILLET WELD

end fillet

side fillet parent metal throat thickness, 0.7 x

L

L

penetration

Ref. BS EN 1011-1 and 2: Welding. Recommendations for welding of

metallic materials.

Structural Steelwork---Welded Connections