1. Different references

1. cold binding plate: hot rolled coil as raw material, at room temperature under the recrystallization temperature to stop rolling products.

2. galvanized plate: refers to the appearance of a layer of zinc plated steel plate.

Second. different characteristics

1. cold binding plate: because it does not stop heating, there is no pitting and oxide sheet defects that are often presented in hot rolling, and the appearance is good and the brightness is high. Moreover, the dimensional accuracy of cold-rolled products is high, and the performance and organization of products can meet some special application requirements, such as electromagnetic properties and deep drawing properties.

2. galvanized sheet: Galvanized sheet due to the different treatment methods in the plating process, the appearance of the state is different, such as ordinary zinc flowers, fine zinc flowers, flat zinc flowers, zinc flowers and phosphating treatment appearance. The German code also rules for appearance levels.

Three. different uses

1. cold tie plate: mostly used in automobile manufacturing, electrical products and so on.

2. Galvanized sheet: 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 home appliance housings, civil chimneys, kitchen utensils and so on.

"Galvanized sheet 275g/㎡" means that the sum of the double-sided galvanized amount of the galvanized sheet per square meter area is 275 grams. The zinc flowers of hot dip galvanized steel plate are larger and more obvious, called "zinc flowers", and the zinc flowers are not fine enough, called "no zinc flowers".

What does having flowers and no flowers mean which is more expensive?

The zinc flowers of hot dip galvanized steel plate are larger and more obvious, called "zinc flowers", and the zinc flowers are finer and less obvious, called "no zinc flowers".

The hot plate substrate is generally made of zinc flowers, the cold plate substrate is generally made of no zinc flowers, and the cold plate is made of no zinc flowers, the surface is more smooth and smooth, the hardness is low, the elongation is high, the directional consistency is good, and the price is more expensive.

Galvanized sheet flowers and flowers are differentiated according to the surface state of galvanized sheet, generally weak eye will know, the surface has a pattern is flowers, there is no flowers. Flowers and no flowers have nothing to do with the material. The material depends on the substrate used for galvanizing, such as Q195, Q345, SPCC and so on. There is also no relationship between thickness and presence of zinc flowers.

There is a galvanized sheet, that is, the surface of the galvanized sheet is printed with a pattern, the appearance looks very bright, beautiful, and is generally used to make home appliance shells, buckets, and so on. There is no pattern on the surface of the flowerless galvanized sheet, which looks not as bright as the flowered galvanized sheet, dark color, and cold plate. There is no difference in performance, mainly in appearance.

There is a flower is the surface of the board has a pattern like a leaf, but also divided into small zinc flowers with large zinc flowers, no flowers is like aluminum plate, flat what pattern is not there

Zinc-iron alloy plate is also called alloyed galvanized plate. The alloying process heats the galvanized strip through the alloying furnace to 550~560 ° C in 5~10 seconds in order to convert the pure zinc layer into an iron-zinc alloy. Its weldability, coating performance, heat resistance, corrosion resistance are better than ordinary galvanized sheet.

Performance and characteristics

1. Suitable for alkaline low iron zinc iron alloy process, coating iron content 0.3 ~ 0.8%;

2. Fine crystal coating, brightness is white;

3. The alloy coating is easy to passivation, and the corrosion resistance of the alloy coating after passivation is more than three times that of the zinc layer passivation;

4. Stable plating solution, easy to maintain, can be hung plating or roll plating (including automatic line);

5. The cost is relatively low, and the original equipment can be used to turn the original zincate galvanizing liquid into a trough.

Use

By alloying, it can be made into superalloy or super alloy, corrosion resistant alloy, high resistance alloy, electric vacuum alloy and other materials with special properties. Widely used in aerospace, aviation, shipbuilding, electronics, electrical, machinery, chemical, electroplating and other industrial sectors.

In the early days, there were more zinc-iron alloys in automobiles, such as gasoline pumps, carburetors, and so on.

Because the surface galvanized liquid contains iron, so the welding performance is better than ordinary galvanized, also has rust resistance and corrosion resistance, the application is very wide.

1. the reliability of galvanized steel plate is good, galvanized layer and steel is metallurgical combination, become a part of the surface, so the durability of the coating is more reliable.

2. galvanized steel plate has corrosion resistance. 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, this zinc coated steel plate is called galvanized steel plate. Galvanizing is an economical and effective rust prevention method that is often used, and about half of the world's zinc production is used in this process. Galvanized steel plate is an important steel anti-corrosion plate, not only because zinc can form a dense protective layer on the surface of the steel, but also because zinc has a cathodic protection effect, when the galvanized layer is damaged, it can still prevent the corrosion of the iron base material through cathodic protection.

3. galvanized steel coating toughness, galvanized layer forms a special metallurgical structure, this structure can withstand mechanical damage during transport and use.

With the continuous expansion of the use of hot galvanized sheet, the following purposes can be achieved by polishing the strip steel in the modern continuous hot dip galvanizing unit:

(1) Improve the flatness and flatness of the sheet, but also the surface of the zinc particle flattening, so that the surface of the strip smooth, which is especially advantageous for later deep drawing and other occasions with higher precision;

② The polishing roll used has been pre-shot peening, so the surface of the plating plate has a certain roughness after polishing. It can improve the adhesion of the coating, but also can store a certain amount of grease, in the deep drawing process, the lubrication of the die is beneficial;

③ For the plating plate after painting treatment, although the surface is controlled into small zinc flowers, small zinc flowers can still be exposed through the paint layer. Therefore, for some high requirements of galvanized sheet, small zinc flower surface needs to go through polishing treatment. This can make the galvanized sheet obtain a more uniform silver appearance;

(4) By finishing, the lower yield point can be reduced to make the yield platform disappear or less obvious, which can prevent the slip line in the future drawing or deep drawing, and improve the possibility of deep drawing.

The coating thickness formula is: Dz = Gz (Sz*dz), where: Dz -- coating thickness mm, Gz -- per square meter coating weight g, Sz -- coating area mm2, dz -- zinc specific gravity, the above formula can be simplified as: Dz = 0.000139Gz

The causes of white rust are: hot dip galvanizing and other acid, alkali, salt and other corrosive media together; Passivation film or anti-film is destroyed; Passivation or oiling effect is not good; The storage warehouse is not well ventilated and damp; Galvanized sheet in the transport of water; Transported at low temperature and stored at high temperature, condensate is formed.

When the hot galvanized sheet is in the humid air, especially when the air contains SiO2, CO2, NO2 and NO and other acidic substances, the surface of the galvanized layer will soon produce loose white rust. The main components of white rust are ZnO and Zn (OH) 2. This kind of white rust not only affects the appearance, but also brings great difficulties to the future use.

There are three ways to test the corrosion resistance of hot-galvanized sheet: salt spray test; Wet test; Erosion test.

Chromate passivation treatment of galvanized sheet can form passivation film, its chemical reaction formula is as follows: Zn+H2GrO4-ZnGrO2=H2

The trivalent chromium in solution passivation group is insoluble in water, and its chemical properties are not active, which plays the skeleton role, while the hexavalent chromium is easily soluble in water, which can play the role of re-passivation when the passivation film scratches, and has the healing effect of passivation film. Therefore, within a certain limit, passivation film can prevent steam or moist air directly erosion galvanized sheet, zinc layer plays a protective role.

large zinc flower is normal zinc flower, according to the normal production process can produce large zinc flower, its crystal core diameter is not less than 0.2mm; The diameter of the crystalline nucleus less than 0.2mm is called small zinc flower, which is generally not identifiable by the naked eye.

Dark spots are formed by further oxidation of white rust. The main causes of white rust are:

Poor passivation, passivation film thickness is not enough or uneven; No oil on the surface or residual water on the strip surface; The surface of the strip contains water when it is rolled up. Passivation not completely dried; Getting wet or rain-soaked during transportation or storage; The storage time of finished products is too long; Galvanized sheet and other acid and alkali and other corrosive media contact or stored together.

The main reasons for zinc layer shedding are: Surface oxidation, silicon compounds, cold bound emulsion is too dirty, NOF section oxidation atmosphere and protective gas dew point is too high, air fuel ratio is unreasonable, hydrogen flow rate is low, furnace aerobic infiltration, strip into the pot temperature is low, RWP section furnace pressure is low and door suction, NOF section furnace temperature is low, Grease evaporation is not enough, zinc pot aluminum content is low, unit speed is too fast, insufficient reduction, zinc liquid residence time is too short, coating thickness.

Known: the production specification is 0.75×1050mm, and the coil weight is 5 tons. What is the length of the coil? (The specific gravity of galvanized sheet is 7.85g/cm3)

Solution: L = G/ (h×b×p) = (5×1000)/(0.785×1.050×7.5) = 808.816m

Answer: The coil is 808.816m long.

Mainly: peeling, scratches, passivation spots, zinc particles, thick edge, air knife stripes, air knife scratches, exposed steel, inclusion, mechanical damage, poor steel base performance, wave edge, ladling bend, inappropriate size, embossing, zinc layer thickness, roll printing, etc.

There are two kinds: air-cooled and water-cooled.

There are three kinds of vertical, horizontal and vertical annealing furnaces.

Product categories: General coil (CQ), structural galvanized sheet (HSLA), deep drawing hot galvanized sheet (DDQ), baking and hardening hot galvanized sheet (BH), duplex steel (DP), TRIP steel (Phase change induced plastic steel), etc.

It can be divided into two types of in-line annealing and out-of-line annealing, which are also called protective gas method and flux method.