What are the quality inspection standards for high-quality galvanized steel sheets?

Galvanized steel sheet is a welded steel sheet with a hot-dip galvanized or electro-galvanized layer on the surface.

Galvanized steel plate is divided into ordinary electrolytic plate and fingerprint-resistant electrolytic plate. The fingerprint-resistant plate is a fingerprint-resistant treatment added to the ordinary electrolytic plate, which can resist sweat. It is generally used on parts without any treatment, and the grade is SECC-N. Ordinary electrolytic plate is divided into phosphating plate and passivation plate. Phosphating is more commonly used, and the grade is SECC-P, commonly known as p material. Passivation plates are divided into oiled and unoiled.

Quality inspection standard:

The quality requirements of high-quality galvanized sheet include specifications, surface, galvanized amount, chemical composition, shape, machine function and packaging.
1. Package
It is divided into two types: galvanized sheet cut to length and coiled galvanized sheet packaging. It is usually packed in iron sheet, lined with moisture-proof paper, and tied with iron waist on the outside, which is firmly tied to prevent the internal galvanized sheets from rubbing against each other.
2. Standard sizes
The product specifications (as below and below) all list the recommended standard thickness, length and width of the galvanized sheet and their allowable faults. 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.

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3. surface
General situation: Due to 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, no spangle and phosphating treatment. Galvanized sheets and galvanized coils cut to length shall not have defects that affect their use, but the coils are allowed to have less deformed parts such as welding parts.
4. Galvanized quantity
Galvanizing Scale Values: Measuring galvanizing is a widely adopted method for determining the thickness of the zinc coating on galvanized sheets. There are two types of galvanizing with the same amount of galvanizing on both sides (that is, equal thickness galvanizing) and two types of galvanizing on both sides (that is, differential 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 to weigh the process performance of the sheet. However, the requirements of various countries in the world for various types of galvanized sheets are not the same. It is generally required that after the galvanized sheet is bent for 180o, the outer coating shall not leave the zinc layer, and the base shall 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. Generally not for product inspection.

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