Welding Galvanized Structural Steel

Welding galvanized steel is a dangerous task since the galvanized zinc coating on the metal becomes extremely toxic when it s heated.

Welding galvanized structural steel.

The intense heat generated with this arc melts the base metal and allows the joining of two components. All commonly prac ticed welding and cutting techniques gas metal arc shielded metal arc man ual metal arc oxyacetylene friction re sistance can be used on galvanized steel see american welding society s. Structural shapes such as angles channels are frequently hot dipped. Electro galvanized steel as its name indicates is a plating process where the steel is placed in an electrically charged solution of.

Hot dipped galvanized steel is dipped into a vat of molten zinc which coats the steel. Aws d 19 0 calls for welds of galvanized steel on areas free of zinc. The challenge is welding over the zinc coating. As long as the zinc oxide gets access to air to burn off.

Techniques for avoiding entrapment of zinc as discussed in sections 6 1 and 6 2 shall be employed. Galvanized steel welds similar to uncoated carbon steel when properly prepped. Arc welding requires striking a low voltage high current arc between an electrode and the workpiece base metal. Welding galvanized steel has gotten a bad reputation over the years rightfully so as the fumes produced during welding can be incredibly dangerous to the welder s health.

It is a great process to prevent corrosion. If you attempt to weld galvanized steel without removing the galvanizing from the weld area the weld puddle will pop blow out and create a health hazard to the welder and any individuals in the immediate area. Welding on galvanized steel can be necessary if the final structure is too large to be dipped in a galvanizing bath or for structures that must be welded in the field. The galvanized steel is removed and allowed to cool.

The weld strength should be the same whether welding galvanized steel or not. Galvanized parts are used in a wide variety of industries including automotive structural steel construction oil field and many more. Preparation of base metal and welding techniques for sheet plate and structural steel are the same as for welding ungalvanized steel. While it is typically a good idea to complete any welding or fabrication before galvanizing the steel which will result in a more corrosion resistant finished product under some circumstances steel must be welded after.

Thus for galvanized structural fabrications the zinc coating should be removed at least 1 4 2 5 10 cm. Take the proper safety precautions by wearing a welding mask a good welding respirator gloves and an apron.