How to Inspect Quality of GI Steel Coil
|16.5.2019||Posted by juniperqq under Advertising & Marketing|
The quality requirements of the GI steel coil with spangles made in China include size, appearance, galvanized quantity, chemical composition, shape, mechanical properties, and packaging, etc.
There are two kinds of packaging: GI steel coils with spangles and GI steel coil with cut length. Generally wrapped in an iron coil, lined with moisture-proof paper, tied with iron waist outside, firmly tied, to prevent internal galvanized coils from rubbing against each other.
2. Specification and Size
The recommended length, width, thickness and allowable deviation of galvanized coils are listed in the relevant product standards (below). In addition, the length and width of the board and the width of the volume can also be determined according to user requirements.
Surface state: Because of the different plating process, the surface state of the GI steel coil is different, such as no zinc flower, ordinary zinc flower, fine zinc flower, flat zinc flower, and phosphating treatment surface, etc. Galvanized coil and GI steel coil cut into fixed length cannot affect the use of defects, but the GI steel coil allows a number of abnormal parts in the welding area.
4. Galvanizing Capacity
Galvanizing quantity: It is a common and effective method to indicate the thickness of the GI steel coil with spangles made in China. There are two kinds of galvanizing: the same amount of galvanizing on both sides (equal thickness galvanizing) and the different amount of galvanizing on both sides (differential thickness galvanizing). The unit of galvanizing quantity is g/m2.
5. Mechanical Properties
a. Tensile test: Generally speaking, only GI steel coils for drawing, deep drawing and structure have the requirement of the tensile property.
b. Bending test: The main item to measure the technological performance of coil metal, but the requirements of various national standards for galvanized coil metal are not the same. Generally, after 180 o bending of the galvanized coil, the outer surface of the coil should not be separated from the zinc layer, and the base of the GI steel coil should not be cracked or broken.
6. Chemical Constituents
The requirements for the chemical composition of galvanized substrates vary from country to country. Generally, finished products are not inspected.