Use underwater or in flowing water
In applications underwater or with frequent exposure to flowing water, the stable protective film layer that is characteristic of ZAM® is difficult to form, so that sometimes ZAM® may gather red rust early without showing superiority to hot-dip zinc-coated steel sheets. Be aware of this when using it in such applications.
・In order not to damage the coating surface, handle the product carefully and do not put any sweat or finger smudges on the surface.
・If the surface should become damaged, repair it.
・ Be careful when removing a coil band because the end of the coil could spring up as it unwinds.
・ Store products securely, so that coils do not tip over and stacked-up cut sheets do not topple.
・ Be careful to prevent water stains and dew condensation. If packaging paper is damaged, repair it.
・If the surface is damaged during processing, it could adversely affect corrosion resistance and paintability.
In particular, some types of lubricating oil may corrode the coating layer during press working. It is therefore necessary to check the type of lubricating oil to be used. When lubricant is used, perform degreasing or other post-treatment after the processing.
・As time passes, a steel sheet tends to harden, resulting in a decrease in workability. To avoid this, use the steel sheet as soon as possible.
Precautions to prevent galvanic corrosion
(1) Avoid direct contact with lead or copper (or copper ion drops)
(2) For metal fittings and attachments, use products made of stainless steel (SUS304) or aluminum or those which are painted or heavily coated with zinc for increased durability.
(3) When using ZAM® in a salt-damaged or snow-covered area, use metal fittings and attachments made of a similar metal (aluminum, zinc-coated metal) or stainless steel insulated properly and treated with an anticorrosive (or a sealing material)
(4) In such applications as lightning conductors where corrosion is likely to occur, insulation tape or aluminum wire should be used.
(Source: Preventive measures of bimetallic corrosion of prepainted/zinc-based coated steel sheets: Hot-dip zinc-coated Committee, The Japan Iron & Steel Federation)
Precautions to prevent corrosion due to
contact with a preservative-treated or
termite resistant wood
ZAM® should not be left in contact with wood containing preservative/ant repellant for an extended period of time. Wood and laminated wood treated with preservatives and ant-repellants (primarily copper-based agents) adversely affect corrosion resistance property of coated steel sheets and prepainted steel sheets. Therefore, where these steel sheets are likely to come in contact with wood materials (parts of the roofs including eaves, roof edges and joints for example), insulation underthatch (roofing stock or butyl tape) should be used for rust prevention and steel-wood direct contact should be avoided.
(Source: Preventive measures of bimetallic corrosion of prepainted/zinc-based coated steel sheets: Hot-dip zinc-coated Committee, The Japan Iron & Steel Federation.)
・When conducting resistance welding, proper care should be taken of the electrodes to remove zinc pickups.
・For coated steel sheets containing ZAM® , coatings evaporate due to heat from welding, so that greater amounts of sputtering and fume are generated than in the case of hot- or cold-rolled steel sheets. Take appropriate safety measures at the time of welding work.
＜Safety measures for welding hot-dip zinc-coated steel sheets＞
1. increase in volume of fume generated by evaporating zinc, and
2. burns or fires due to larger volumes of spatters generated.
Especially, since fume is inevitable when welding hot-dip zinc-coated steel sheets, proper measures should be put in place. Health hazards of zinc are shown in the table.
Effects of zinc on the human body
|Carcinogenicity||Has not been confirmed at the present time|
|Acute toxicity||It is known that inhaling a large quantity of zinc fumes results in a fever several hours later (zinc fume fever). The affected personrecovers naturally in about 24 hours. The mechanism by which this occurs is not understood.|
|Chronic toxicity||No evidence has been found that zinc causes symptoms of chronic toxicity.|
|Other effects||Zinc deficiency can cause delayed growth, reduced functioning of the gonads, depression, loss of appetite, and other symptoms.|