The quality requirements of high-grade galvanized sheet include specifications and dimensions, surface, galvanized amount, chemical composition, plate shape, machine function and packaging.
1. package
There are two types: galvanized sheet cut to length and galvanized sheet packaging. Generally, iron sheet packaging is lined with moisture-proof paper, and the outside is tied with iron waist to prevent the galvanized sheets from rubbing against each other.
2. Standard sizes
The relevant product standards (such as the following and) list the recommended standard thickness, length and width of the galvanized sheet 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 general situation of galvanized sheet is also different because of the different treatment methods in the coating process, such as the general spangle, fine spangle, flat spangle, spangle-free and phosphating treatment. Galvanized sheets and galvanized coils cut to a fixed length shall not have any disadvantages that affect the use, but the coils are allowed to have less deformed parts such as welding parts.
4. Galvanized amount
Galvanized amount scale value: Measuring the galvanized amount is a widely adopted method to determine the thickness of the zinc layer of the galvanized sheet. There are two sides with the same galvanizing amount on both sides (that is, equal-thickness galvanizing) and unequal galvanizing on both sides (that is, differential thickness galvanizing). The unit of galvanizing amount is g/m2.
5. Machine function
(1) Tensile test: Generally speaking, as long as the galvanized sheet for layout, drawing and deep drawing has tensile performance requirements.
(2) Bending experiment: It is an important item that weighs the technical performance of thin plates. However, all countries in the world have different requirements for various types of galvanized sheets. It is generally required that after the galvanized sheet is bent 180o, the outer coating 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 in the world. If Japan has this requirement, the United States does not. Generally, product inspection is not performed.
7. Plate shape
There are two goals for weighing the black and white of the board shape, namely, straightness and sickle bend. The flatness of the board and the maximum allowable scale of the sickle bend must be delineated.
