How to identify good and bad galvanized coil

GNEE galvanized coils can be subjected to electrochemical and physico-mechanical tests to obtain data on electrochemical behavior and physical properties; e.g., bonding, corrosion resistance, coating thickness, etc., depending on the specific application requirements. Supplementary: quality inspection standards for galvanized steel:

According to the production and processing methods, galvanized steel can be divided into the following categories: hot-dipped galvanized steel (commonly known as galvanized iron), electro-galvanized steel, single-sided or double-sided differential thickness galvanized steel, alloy composite galvanized steel, etc. In addition to the above, there are also colorful galvanized steel (commonly known as color plate), stamped coated galvanized steel, PVC laminated galvanized steel and so on.

In addition, the galvanized steel sheets can be classified into general use, roofing use, building exterior board use, structural use, tile ridge board use, stretching use and deep drawing use, etc. according to the use.

The quality requirements of high-quality grade galvanized steel include specifications and dimensions, appearance, galvanizing amount, chemical composition, plate shape, mechanical properties and packaging and other aspects.

1. Packaging

Divided into cut-to-length galvanized sheet and rolled galvanized sheet packaging of two kinds. General tin packaging, lined with moisture-proof paper, outside the iron waist tied, tied securely to prevent friction within the galvanized sheet each other.

2. Specification and size

The relevant product standards (to the following and) are listed in the recommended standard thickness, length and width of galvanized sheet and its allowable deviation. In addition, the width and length of the sheet and the width of the roll can also be determined according to user requirements. 3. Appearance

Surface state: galvanized sheet due to the coating process in the treatment of different ways, the surface state is different, such as ordinary zinc flower, fine zinc flower, flat zinc flower, no zinc flower and phosphate treatment of the surface. Cut to length galvanized sheet and galvanized coil shall not exist to affect the use of defects (described below), but the coil is allowed to have a number of abnormal parts such as welded parts.

4. Galvanized quantity

Galvanized amount of standard value: galvanized amount of zinc is expressed in galvanized sheet of zinc layer thickness of a commonly used and effective method. There are two sides of the same amount of galvanization (i.e., equal thickness galvanized) and two sides of the amount of galvanization is different (i.e., the difference between the thickness of galvanized) two kinds. The unit of galvanization is g/m2.

5. Mechanical properties

(1) tensile test: generally speaking, only structural, tensile and deep drawing galvanized sheet with tensile performance requirements.

(2) bending test: is the main project to measure the process performance of the sheet. However, national standards for various galvanized sheet requirements are not consistent. General requirements for galvanized sheet bending 180o, the outer surface shall not have zinc layer detachment, the plate base shall not have cracking and fracture.

6. Chemical composition

The requirements of the chemical composition of the galvanized substrate, the standard provisions of different countries. Such as Japan does not require, the United States requires. Generally not for finished product inspection.