The quality requirements of good grade galvanized sheet include specifications and dimensions, surface, zinc content, chemical composition, plate shape, machine function and packaging.
It can be divided into two kinds: galvanized sheet cut into fixed length and galvanized strip package. Generally, iron sheet packing is lined with moisture-proof paper, and the outer part is tied with iron waist to prevent friction
between galvanized sheets inside.
2. Specifications and dimensions
The scale of the product concerned (e.g. below and) lists the recommended gauge thickness, length and width of galvanized sheet and its allowable defects. In addition, the
width and length of the board and the width of the roll can also be determined according to the user's request.
General situation: due to different treatment methods in the coating process of galvanized sheet, the general situation
is also different, such as the general situation of common zinc, fine zinc, flat zinc, no zinc and phosphating. The galvanized sheet and galvanized coil cut into fixed length shall not have defects that affect the use (as described below), but the coil
plate is allowed to have welding parts and other parts which are not deformed.
4. Galvanizing amount
Galvanizing quantity scale value: galvanizing amount is a widely adopted and useful method to indicate zinc coating thickness of galvanized
sheet. There are two kinds of same galvanizing amount on both sides (i.e. equal thickness galvanizing) and different zinc plating amount (i.e. differential thickness galvanizing) on both sides. The unit of galvanizing amount is g / m2.
(1) Tensile test: Generally speaking, as long as layout, drawing and deep drawing galvanized sheet have tensile function request.
(2) Bending experiment: it is an important item to weigh the technological function of thin plate. However,
the requirements for various types of galvanized sheet are different in different countries. Generally, it is required that after the galvanized sheet is bent for 180 years, there shall be no zinc layer left on the outside, and the plate base shall be
free from cracking and fracture.
6. Chemical composition
For the request of chemical composition of galvanized substrate, different countries have different standards. If Japan does not request, the United States does. Generally, no product
inspection is required.
7. Plate shape
There are two goals to weigh the shape of black and white, namely straightness and sickle bend. The maximum allowable values of straightness and sickle bend of plates are defined.