The quality requirements of excellent grade galvanized sheet include specifications, surface, galvanized amount, chemical composition, plate shape, machine function and packaging.
1. package
It is divided into two types: galvanized sheet cut to length and galvanized sheet with coil. It is usually packed in iron sheet, lined with moisture-proof paper, and tied with an iron waistband, which is firmly tied to prevent the internal galvanized plates from rubbing against each other.
2. Standard sizes
Relevant product standards (as described below) list the recommended thickness, length and width of galvanized sheets and their allowable defects. In addition, the width and length of the board and the width of the roll can also be determined according to user requirements.
3. surface
General situation: The galvanized sheet has different disposal methods due to different disposal methods in the coating process, such as the general zinc flower, fine zinc flower, flat zinc flower, zinc-free flower and phosphate treatment. The galvanized sheets and galvanized coils cut into lengths of fixed length shall not have any shortcomings that affect the use, but the coils are allowed to have less deformed parts such as welded parts.
4. Galvanized amount
Scale value of galvanized amount: Measuring galvanized amount is a widely adopted method to determine the thickness of zinc layer of galvanized sheet. There are two types of galvanization on both sides (the same thickness galvanization) and galvanization on both sides (ie the difference thickness galvanization). The unit of galvanizing amount is g/m2.
5. Machine function
(1) Tensile test: Generally speaking, as long as the galvanized sheets for layout, drawing and deep drawing have tensile performance requirements.
(2) Bending experiment: It is an important item to weigh the function of thin plate technology. However, the requirements of various galvanized sheets in different countries are not the same. It is generally required that after the galvanized sheet is bent 180o, the outer plating layer must not leave the zinc layer, and the board base must not be cracked or broken.
6. chemical composition
The requirements for the chemical composition of galvanized substrates vary from country to country. If Japan has this requirement, the United States does not. Product inspection is generally not conducted.
7. Plate shape
There are two goals in weighing the shape of black and white, namely straightness and sickle bending. The flatness of the board and the maximum allowable value scale of the sickle bend must be defined.
