Learn about galvanized sheet

Galvanized plate

Galvanized sheet is a steel plate with a layer of zinc plated on the surface. Galvanizing is an economical and effective anticorrosion method that is often used, and about half of the world's zinc production is used in this process.

01 Action

Galvanized steel plate is to prevent corrosion on the surface of the steel plate to extend its service life, coated with a layer of metal zinc on the surface of the steel plate, the zinc-coated steel plate is called galvanized plate.

02 Classification

According to production and processing methods can be divided into the following categories:

① Hot dip galvanized steel plate. The sheet steel is immersed in the melted zinc tank so that the surface is adhered to a layer of zinc sheet steel. At present, it is mainly produced by continuous galvanizing process, that is, continuous immersion of rolled steel plates in melting zinc plating tanks to make galvanized steel plates;

② Alloyed galvanized steel plate. This steel plate is also made by hot dipping, but after the tank is out, it is immediately heated to about 500 ° C to generate an alloy film of zinc and iron. The galvanized sheet has good adhesion and weldability of coating.

③ Electric galvanized steel plate. The galvanized steel plate made by electroplating has good workability. However, the coating is thin and the corrosion resistance is not as good as that of hot-dip galvanized sheet.

④ Single-sided plating and double-sided differential galvanized steel plate. Single-sided galvanized steel, that is, products that are only galvanized on one side. It has better adaptability than double-sided galvanized sheet in welding, coating, anti-rust treatment, processing and so on. In order to overcome the shortcomings of uncoated zinc on one side, there is a galvanized sheet coated with a thin layer of zinc on the other side, that is, double-sided differential galvanized sheet;

⑤ Alloy, composite galvanized steel plate. It is a steel plate made of zinc and other metals such as lead and zinc alloy or even composite plating. This steel plate not only has excellent anti-rust performance, but also has good coating performance;

In addition to the above five kinds, there are color galvanized steel plate, printed coated galvanized steel plate, polyvinyl chloride laminated galvanized steel plate and so on. But the most commonly used is still hot dip galvanized sheet.

03 Main production plants and import production countries

① Domestic main production plants: Quantong, WisCO, Angang, Baosteel Group, MCC Hengtong, Shougang, Panzhihua Steel, Handan Steel, Masteel, etc.;

② The main foreign production countries are Japan, Germany, Russia, France, South Korea and so on.

The relevant product standards list the recommended standard thickness, length and width of galvanized sheets and their allowable deviations. The thickness deviation is generally 0.03mm, the length and width deviation is generally 5mm, and the thickness of the plate is generally between 0.4-3.2.

04 Appearance

(1) Surface state: Because of the different treatment methods in the plating process, the surface state of the galvanized plate is also different, such as ordinary zinc flowers, fine zinc flowers, flat zinc flowers, zinc flowers and phosphating surface. The German standard also provides for surface grades.

(2) Galvanized sheet should have a good appearance, no defects harmful to the use of the product, such as no plating, holes, cracks and scum, more than thick plating, abrasion, chromic acid dirt, white rust, etc. Foreign standards are not very clear about the specific appearance defects. Some specific defects should be specified in the contract when ordering.

05 Galvanizing amount

Standard value of galvanizing amount: galvanizing amount is a generally used effective method to indicate the thickness of zinc layer of galvanized sheet. The unit of galvanized quantity is g/m2. The provisions of the Japanese, American and German standards on the amount of galvanized sheet steel are detailed as follows.

06 Mechanical Properties

(1) Tensile test:

Galvanized sheet steel index (unit: g/m2)

JISG3302 Z12 Z18 Z22 Z25 Z27 Z35 Z43 Z50 Z60

Galvanizing quantity 120 180 220 250 270 350 430 500 600

ASTMA525 generation A40 A60 G60 G90 G115 G140 G165 G185 G210

Galvanizing amount 122 183 183 275 351 427 503 564 640

DIN1716 generation 100 200 275 350 450 600

Galvanizing quantity 100 200 275 350 450 600

① Performance indicators: Generally speaking, only structural, drawing and deep drawing galvanized sheets have tensile performance requirements. The structural galvanized sheet requires yield point, tensile strength and elongation, etc. Only elongation is required for stretching. For specific values, see the relevant product standards in "8" of this section;

(2) Test method: The same as the general sheet steel test method, see the relevant standards provided by "8" and the test method standards listed in "ordinary carbon steel sheet steel".

(2) Bending test:

Bending test is the main project to measure the process performance of sheet metal, but the national standards for various galvanized sheet requirements are not consistent, the United States standard in addition to the structural level, the rest do not require bending and tensile test. In Japan, bending tests are required except for structural grade, building corrugated plate and general corrugated plate.

Requirements: Generally, after the galvanized sheet is bent for 180 years, the outer surface shall not be separated from the zinc layer, and the plate base shall not be cracked and broken.

07 Chemical Composition

The requirements for the chemical composition of galvanized sheet substrate are different in national standards, such as Japan does not require it, and the United States requires it. Generally no finished product inspection.

08 Packaging is divided into galvanized sheet cut to a certain length and coil galvanized sheet packaging two kinds. Generally, it is packed in iron sheet, lined with moisture-proof paper, and bound on the bracket with iron kidneys. The binding should be firm to prevent the internal galvanized sheet from rubbing with each other.

09 Galvanized sheet foreign standards

(1) Product standards:

JIS G3302-94 galvanized steel plate;

JIS G3312-94 Painted galvanized iron sheet;

JIS G3313-90 (96) electric galvanized steel sheet and steel strip; General requirements for hot-dip galvanized sheet steel;

ASTM A526-90 Commercial Grade Hot Dip Galvanized Sheet Steel;

ASTMA 527-90 (75) bite molding grade hot dip galvanized sheet steel;

Astma528-90 deep drawing grade hot dip galvanized sheet steel; Hot dip galvanized sheet steel for roofing and siding;

Astma444-89 Hot dip galvanized steel sheet for ditches;

ASTM A446-9 3 Structural Grade Hot Dip Galvanized Sheet Steel;

Astma599-92 Cold rolled galvanized steel sheet;

Astma642-90 Hot dip galvanized special deoxidized deep drawing grade sheet steel;

Γ OCT7118-78 galvanized sheet steel;

Dinen 10142-91 Part 1 Low carbon steel hot dip galvanized steel strips and plates;

Dinen 1012-92 Part 2 Hot dip galvanized sheet steel.

(2) Test method standard:

JIS H0401-83 Test method for hot dip galvanizing;

Din 50952-69 Test method for hot dip galvanizing.

(3) Use, technical indicators, performance specifications

Galvanized strip steel products are mainly used in construction, light industry, automobile, agriculture, animal husbandry, fishery and commercial industries. The construction industry is mainly used for the manufacture of anti-corrosion industrial and civil building roof panels, roof grilles, etc. The light industry uses it to manufacture household appliance shells, civil chimneys, kitchen utensils, etc., and the automotive industry is mainly used to manufacture corrosion-resistant parts of cars. Agriculture, animal husbandry and fisheries are mainly used as food storage and transportation, meat and aquatic products frozen processing equipment; Commercial mainly used as materials storage and transportation, packaging tools, etc.

List of technical index, performance and specification of galvanized sheet

Hot dip galvanized steel sheet (roll) surface treatment

L Chromic acid passivation

Y oiling

LY chromic acid passivation with oil

GZ Optical machine polishing

Surface structure

Surface structure features for use

Normal zinc flowers (Z) zinc flowers obtained by condensation of the zinc layer under normal conditions after galvanizing are generally used

GZ is used to finish the galvanized plate and smooth the zinc flower on the surface of the galvanized plate, which is mainly used as the substrate of the color coated plate

Medium width galvanized sheet

Workability Yield strength Tensile strength elongation % 180o Cold bending

Common PV-270-500 d=0, intact, not dezinced Deep drawing SC -270-380 ≥30 d=0, intact, not dezinced

Mechanical bite JY-270-500 -- d=0, good, no dezincing Super deep drawing SC -270-380 ≥30 d=0, good, no dezincing

Structure JG ≥240 ≥370 ≥18 d=0, intact, no dezincing