HOME

Forming

GALVABOND™ steel can be formed (almost as readily as uncoated cold rolled sheet) in a variety of ways, from simple roll forming and brake pressing to complex and intricate stamping.

However, it is known that galvanized coating exhibits frictional characteristics that are different from uncoated steel. Thus, lubricants, die materials and other elements of fabrication must be compatible with the coating to optimize productivity. In stamping and forming operations, it is advantageous to use dies that are harder and smoother. than would be used for the same uncoated steel sheet. When proper attention has been given to forming parameters, hot-dip galvanized sheet is essentially as formable as cold rolled sheet that possesses similar ductility.

Jointing

Soldering

Soldering is an established method for joining galvanized sheet or attaching solderable items to galvanized coatings. Galvanized sheet can be readily soldered with many types of conventional solders and fluxes. Lead/tin solder alloys are typically used. Flux residues should be removed after soldering to prevent corrosive damage to the zinc coating.

Welding

GALVABOND can be readily welded by the same methods used to weld cold rolled sheet. For example, spot welding is readily performed, but caution must be applied to avoid more rapid deterioration of the spot-welding electrodes. For metal-arc welding and other high temperature welding methods, precautions must be taken into considerations to avoid porosity and cracking of the weld that can be caused by penetration of zinc into the weld pool.

Electric Resistance Welding

1. Spot Welding

Welding conditions for galvanized sheet will differ somewhat from those used for welding hot rolled or cold rolled steel due to lower surface contact resistance. Generally, higher electrode forces and higher welding currents and/or longer weld­cycle times are required to produce the same fused-zone diameter in galvanized and uncoated sheets. The use of copper alloy, is preferred for spot-welding galvanized sheet.

2. Seam Welding

Conventional seam welding equipment can be used for welding lap joints made with galvanized sheet. Seam welding of galvanized steel sheet can be considered to be continuous spot welding (the guidelines for spot welding should be followed for seam welding) to produce acceptable welds, the procedures used for cold rolled sheet should be modified toward slightly narrower electrode width, higher electrode force, higher welding current and slightly lower welding speed.

Fastening

Any fastener suitable for use with sheet metal can be used to join GALVABOND™ steel sheet to itself or to other parts, provided the fastener design is appropriate for the structural requirement of the application. Acceptable devices include common fasteners like nuts and bolts, screws and rivets of all types.

Corrosion characteristics of the fastener material should be carefully considered from two standpoints, first, the fastener should be equally as corrosion resistant as the GALVABOND™ coating to ensure long life of the fabricated product. Second, the fmtener material should be compatible with the coating; that is, it should be selected to avoid accelerated corrosion caused by intimate contact between certain, types of dissimilar metals.

Adhesive Bonding

Adhesive bonding is a viable technique for joining coated steel sheet to other coated or uncoated sheet. It is an excellent method of joining dissimilar steel sheet products. It does not alter the properties of steel or its coating. It can serve to enhance product design, so that mechanical fasteners and/or welding can be avoided.

Sealants

Sealants are often used between overlapping areas of steel sheet to form watertight joints and to achieve superior environmental durability. Neutral-cure silicone rubber sealants are recommended for use with GALVABOND™ steel sheet. Needing no primer, these materials are flexible and non-corrosive as well as resistant to heat, cold, water and ultraviolet rays. In selecting a silicone rubber sealant, avoid those materials that contain acetic acid or amines, which can promote corrosion during the early stages of curing.

Other types of sealants, like butyl rubber and styrene butadiene rubber, may also be used as alternatives.