Galvanized steel plate is to prevent the surface of the steel plate from being corroded and prolong its service life. The surface of ordinary steel plate is coated with a layer of metal zinc. This kind of zinc-coated steel plate is called galvanized steel plate.
Quality requirements for high-grade galvanized sheets include specifications and dimensions, surface, galvanized amount, chemical composition, plate shape, machine function and packaging.
1. Packaging
Packaging is divided into two types: galvanized sheet cut to length and coiled galvanized sheet. General iron sheet packaging, lined with moisture-proof paper, and tied with iron waist on the outside to prevent the inner galvanized sheet from rubbing against each other
2. Size
Relevant product standards (such as the following and) list the recommended standard thickness, length and width of 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: because of the different treatment methods in the coating process, the general situation of the galvanized sheet is also different, such as the general spangle, fine spangle, flat spangle, zinc-free spangle and phosphating treatment. Galvanized sheets and galvanized coils cut to length should not have any disadvantages that affect their use (as shown below), but the coils are allowed to have some non-deformed parts such as welding parts.
4. Galvanizing amount
Galvanized amount scale value: The amount of galvanized is a widely adopted useful method that implies the thickness of the zinc layer of the galvanized sheet. There are two sides with the same galvanizing amount on both sides (i.e. equal-thickness galvanizing) and two different sides (i.e. 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, national standards have different requirements for various types of galvanized sheets. It is generally required that after the galvanized sheet is bent 180o, the outer surface of the zinc layer shall not leave the zinc layer, and the board base shall not be cracked or broken.
6. Chemical composition
The requirements for the chemical composition of galvanized substrates are divided into different national standards. If Japan does not request it, the United States does. Generally, no product inspection is made.
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.
