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Product Description

Galvanized channel steel is an effective metal anti-corrosion method, which is mainly used in metal structural facilities in various industries. Hot-dip galvanized channel steel can be divided into hot-dip galvanized channel steel and hot-blown galvanized channel steel according to different galvanizing processes. A zinc layer is attached to the surface of the component, so as to achieve the purpose of anti-corrosion.

Process flow

The process flow of hot-dip galvanized channel steel: raw material inspection → pickling → cleaning → zinc assistance → drying → galvanizing → cooling → passivation → cleaning → finished product inspection → inspection and packaging, etc.
According to the custom, the hot-dip galvanizing process is often divided into two categories: off-line annealing and in-line annealing according to different pre-plating treatment methods.
1. Off-line annealing Off-
line annealing means that before the hot-rolled or cold-rolled steel enters the hot-dip galvanizing line, recrystallization annealing is first performed in a bottom-drawing annealing furnace or a bell-type annealing furnace, so that there is no annealing in the galvanizing line. process. Steel must maintain a clean pure iron active surface free of oxides and other contaminants prior to hot dip galvanizing. This method is to first remove the annealed surface iron oxide scale by pickling, and then coat a layer of zinc chloride or a solvent composed of ammonium chloride and zinc chloride for protection, so as to prevent the steel from being oxidized again. .
(1)
The solvent on the surface of wet hot-dip galvanized steel enters the zinc liquid covered with molten solvent without drying (that is, the surface is still wet) for hot-dip galvanizing. The disadvantages of this method are: a. It can only be galvanized
in the lead-free state, and the alloy layer of the coating is very thick and the adhesion is very bad;
Deposited on the bottom of the pot (because the specific gravity of zinc slag is greater than that of zinc liquid but less than that of lead liquid), so that the steel contaminates the surface by passing through the zinc layer.
Therefore, wet hot-dip galvanizing has been basically eliminated.
(2)
The method of single steel generally uses hot-rolled laminated sheets as raw materials. First, the annealed steel is sent to the pickling workshop, and the oxygen hot-dip galvanized iron sheet on the surface of the steel is removed with sulfuric acid or hydrochloric acid. After pickling, the steel is immediately immersed in the water tank for galvanizing, which can prevent the steel from re-oxidizing. After pickling, washing with water, squeezing, drying, and entering into a zinc pot (the temperature has been kept at 445-465 ℃), hot-dip galvanizing, and then oiling and chromizing. The quality of hot-dip galvanized sheet produced by this method is significantly improved than that of wet galvanized products, and it is only valuable for small-scale production.
(3) Wheeling Fever
The continuous galvanizing production line includes a series of pretreatment processes such as alkali degreasing, hydrochloric acid pickling, water washing, solvent coating, drying, etc., and the original plate needs to be annealed in a bell furnace before entering the galvanizing line for galvanizing. The production process of this method is complicated, and the production cost is high. More importantly, the products produced by this method often have solvent defects, which affect the corrosion resistance of the coating. And the AL in the zinc pot often reacts with the solvent on the steel surface to form aluminum trichloride and is consumed, and the adhesion of the coating becomes worse. Therefore, although this method has been in existence for nearly 30 years, it has not been developed in the world hot-dip galvanizing industry.
2. In-line annealing In-
line annealing is to provide coils directly from the cold rolling or hot rolling workshop as the original plate of hot-dip galvanizing, and conduct gas-shielded recrystallization annealing in the hot-dip galvanizing line. The hot-dip galvanizing methods that belong to this industry include: Sendzimir method, improved Sendzimir method, American Steel Union method (same as Japan's Kawasaki method), Silas method, Sharon method.
(1) The Sendzimir method
combines the annealing process and the hot-dip galvanizing process. The in-line annealing mainly consists of an oxidation furnace and a reduction furnace. The strip steel is directly heated to about 450 degrees by the gas flame in the oxidation furnace, and the residual rolling oil on the surface of the strip steel is burned off to purify the surface. Then the strip is heated to 700-800 degrees to complete recrystallization annealing, and the temperature before entering the zinc pot is controlled at about 480 degrees through the cooling section, and finally enters the zinc pot for galvanizing without contact with air. Therefore, the output of Sendzimir method High, galvanized quality is better, this method has been widely used.
(2) The American Steel Union method
is a variant of the Sendzimir method. It only uses an alkaline electrolytic degreasing tank to replace the degreasing effect of the oxidation furnace. The remaining processes are basically the same as the Sendzimir method. After the original board enters the operation line, it is first electrolytically degreased, then washed and dried, and then passed through a reduction furnace with protective gas for recrystallization annealing, and finally enters the zinc pot under the condition of sealing for hot-dip galvanizing. In this method, since the strip is not heated by the oxidation furnace, the oxide film on the surface is relatively thin, and the hydrogen content of the protective gas in the reduction furnace can be appropriately reduced. In this way, it is beneficial to furnace safety and to reduce production costs. However, since the strip steel enters the reduction furnace without preheating, this undoubtedly increases the heat load of the reduction furnace and affects the life of the furnace. Therefore, this method has not been widely used.
(3) The Silas Act
Also known as direct flame heating method; first strip steel is degreasing with alkali, then the oxide scale on the surface is removed with hydrochloric acid, washed with water, dried, and then entered into a vertical in-line annealing furnace directly heated by gas flame. The flame burning ratio of gas and air enables incomplete flame burning in the case of excess gas and insufficient oxygen, thereby creating a reducing atmosphere in the furnace. It is rapidly heated to reach the recrystallization temperature and the strip is cooled in a low hydrogen protective atmosphere. Finally, it is immersed in a zinc solution under a closed condition for hot-dip galvanizing. The method has compact equipment, low investment cost and high output (up to 50/hour). However, the production process is complicated, especially when the unit stops running, in order to avoid burning the strip, it is necessary to adopt the method of moving the furnace away from the strip, which has many operational problems. Therefore, this method is rarely used in the hot-dip galvanizing industry.
(4) Sharon method
In 1939, the American Sharon Company put into production a new type of hot-dip galvanizing unit, so it is also called Sharon method. This method is to spray hydrogen chloride gas to the strip in the annealing furnace to make the strip reach the recrystallization temperature, so it is also called the gas pickling method. The use of hydrogen chloride gas pickling can not only remove the oxide skin on the surface of the strip, but also remove the grease on the surface of the strip. Since the surface of the strip is corroded by the oxidizing gas to form a pockmarked surface, the coating obtained by using the Sharon method adheres to the surface. Sex is particularly good. However, due to the serious corrosion of the equipment, it causes high equipment maintenance and update costs. Therefore, this method is rarely used.
(5) Improved Sendzimir
It is a more superior hot-dip galvanizing process; it connects the independent oxidation furnace and reduction furnace in the Sendzimir method by a passage with a smaller cross-sectional area, which includes preheating furnace, The whole annealing furnace including the reduction furnace and the cooling section constitutes an organic whole. Practice has proved that this method has many advantages: high quality, high yield, low consumption, safety and other advantages have been gradually recognized by people. Its development speed is very fast. Almost all new operation lines since 1965 have adopted this method. In recent years, most of the old Sendzimir units have also been transformed according to this method.

Features

1) It has a thick and dense pure zinc layer covering the steel surface, which can avoid the contact between the steel substrate and any corrosive solution and protect the steel substrate from corrosion. In the general atmosphere, the surface of the zinc layer forms a very thin and dense zinc oxide layer surface, which is difficult to dissolve in water, so it plays a certain protective role on the steel substrate. If zinc oxide and other components in the atmosphere form insoluble zinc salts, the anti-corrosion effect is more ideal.
(2) It has an iron-zinc alloy layer, which is densely bonded and exhibits unique corrosion resistance in marine salt spray atmosphere and industrial atmosphere;
(3) Due to the firm bonding, zinc-iron is mutually soluble and has strong wear resistance;
(4) Due to the good ductility of zinc, its alloy layer is firmly attached to the steel base, so the hot-dip galvanized parts can be formed by cold punching, rolling, wire drawing, bending, etc. without damaging the coating;
(5) Steel structural parts After hot-dip galvanizing, it is equivalent to one-time annealing treatment, which can effectively improve the mechanical properties of the steel matrix, eliminate the stress during the forming and welding of the steel parts, and facilitate the turning of the steel structural parts.
(6) The surface of the parts after hot-dip galvanizing is bright and beautiful.
(7) The pure zinc layer is the most plastic galvanized layer in hot-dip galvanizing. Its properties are basically close to that of pure zinc, and it is ductile, so it is full of flexibility.

Channel steel theoretical weight table:

Product name

Specification

high

leg width

waist thick

Riju

Hot-dip galvanized channel steel

5#

50

37

4.5

5.438

Hot-dip galvanized channel steel

6.3#

63

40

4.8

6.634

Hot-dip galvanized channel steel

8#

80

43

5

8.045

Hot-dip galvanized channel steel

10#

100

48

5.3

10.007

Hot-dip galvanized channel steel

12#

120

53

5.5

12.059

Hot-dip galvanized channel steel

12.6#

126

53

5.5

12.318

Hot-dip galvanized channel steel

14#a

140

58

6

14.535

Hot-dip galvanized channel steel

14#b

140

60

8

16.733

Hot-dip galvanized channel steel

16#a

160

63

6.5

17.24

Hot-dip galvanized channel steel

16#b

160

65

8.5

19.752

Hot-dip galvanized channel steel

18#a

180

68

7

20.174

Hot-dip galvanized channel steel

18#b

180

70

9

twenty three

Hot-dip galvanized channel steel

20#a

200

73

7

22.637

Hot-dip galvanized channel steel

20#b

200

75

9

25.777

Hot-dip galvanized channel steel

22#a

220

77

7

24.999

Hot-dip galvanized channel steel

22#b

220

79

9

28.453

Hot-dip galvanized channel steel

25#a

250

78

7

27.41

Hot-dip galvanized channel steel

25#b

250

80

9

31.335

Hot-dip galvanized channel steel

25#c

250

82

11

35.26

Hot-dip galvanized channel steel

28#a

280

82

7.5

31.427

Hot-dip galvanized channel steel

28#b

280

84

9.5

35.832

Hot-dip galvanized channel steel

28#c

280

86

11

40.219

Hot-dip galvanized channel steel

32#a

320

88

8

38.083

Hot-dip galvanized channel steel

32#b

320

90

10

43.107

Hot-dip galvanized channel steel

32#c

320

92

12

48.131

Hot-dip galvanized channel steel

36#a

360

96

9

47.814

Hot-dip galvanized channel steel

36#b

360

98

11

53.466

Hot-dip galvanized channel steel

36#c

360

100

13

59.118

Hot-dip galvanized channel steel

40#a

400

100

10

58.928

Hot-dip galvanized channel steel

40#b

400

102

12.5

65.208

Hot-dip galvanized channel steel

40#c

400

104

14.5

71.488

Material

Q235/Q235B/Q345/Q345B/SS400

Type

U/C Shape Channel

Surface treatment

polish;painted;galvanzied;punched

MOQ

Min trial order 25 ton each thickness

Payment

L/C at sight,30%T/T ,70% balance against B/L copy,Alibaba Trade Assurance



Specifications

H= 80mm-350mm

B= 40mm-80mm

C= 15mm-25mm

T= 1.5mm-3.5mm

Length=1-12 meters

Surface Treatment

HDG(hot dipped galvanized ),Pre-galvanized,Electrical-galvanizing(yellow or white),powdercoating(Black,Green,White,Grey,Blue)etc.

Dimensions

13/16"x 1-5/8" or 1-5/8" x 1-5/8",1-1/2"x1-1/2",3/4"x1-1/2"

Lengths

Either 10FT or 20FT or cut into the length according to clients' requirements

Size

41mm*21mm or 41mm*41mm back to back 41*41mm, 41*62mm,41*82mm,and so on

Thickness

1.5mm, 1.8mm,1.9mm,2.0mm, 2.3mm,2.5mm ,2.7mm

Holes

28*14mm,18*9mm,13.5*63mm,11*25mm,11*30mm etc

Style

Plain or Slotted

MOQ

5 Tons

Packaging

In Bundles and fasten with steel strips or by wooden pallets

Channel steel calculation formula (kg/m) W=0.00785 ×[hd+2t (b - d )+0.349 (R2 - r 2 )] h= height
b= leg length
d= waist thickness
t= average leg thickness
R= inner Arc radius
r = end arc radius, for example, find the weight per m of channel steel of 80 mm × 43 mm × 5 mm.
It is found from the catalogue of metallurgical products that the channel steel t is 8, R is 8, and r is 4,
then the weight per m = 0.00785 × [80 × 5 + 2 × 8 × (43 - 5 ) + 0.349 × (82-4 2)]=8.04kg

型材证书和客户

Product Advantages
01.Anticorrosive:17 years in heavy industrial areas.
02.Cheap:The cost of hot-dip galvanizing is lower than that of other coatings.
03.Reliable:The zinc coating is metallurgically bonded to the steel and forms part of the steel surface,so the coating is more durable.
04.Strong toughness:The galvanized layer forms a special metallurgical structure that can withstand mechanical damage during transportation and use.
05.Comprehensive protection:Every part of the plated piece can be galvanized,and is fully protected even in depressions,sharp corners,and hidden places.
06.Save time and energy:Galvanizing process is faster than other coating methods.


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