Hot-rolled sheet Hot-rolled sheet is the most important type of steel in the sheet, and is widely used in industrial production industries such as containers, automobiles, railway locomotives, pipes, and steel cylinders. Hot rolled sheets are mainly rolled by continuous hot rolling mills. The hot-rolled sheet finally rolled by the continuous rolling mill can also be pickled, annealed, and then rolled into a coil, which is called a hot-rolled sheet. Sheet steel is usually marketed in coils and individual sheets cut to length and width. After the coil is uncoiled, it is cut according to a certain width and length to obtain a hot-rolled sheet. Hot-rolled sheets can be rolled from different steel types according to the application. Therefore, the types of hot-rolled sheets are divided according to steel types. The following is a brief introduction to the main uses of various types of hot-rolled sheets. a. Carbon structural steel and low alloy structural steel hot-rolled sheet (GB912-89) This type of hot-rolled sheet is widely used, and is widely used in various sheet stampings and metal products that do not require deep drawing processing, such as machine covers , switch boxes, filing cabinets, etc., are also commonly used as blanks for straight seam welded pipes, spiral welded pipes and cold-formed steel. b. High-quality carbon structural steel hot-rolled sheet (GB710-91) This type of hot-rolled sheet is mainly used for general stamping metal products for structural parts in machinery, transportation and aviation industries. c. Alloy structural steel hot-rolled sheet (GB/T5132-93) This type of hot-rolled sheet is mainly used for structural parts and components in machinery, construction and transportation industries. d. Spring steel hot-rolled sheet (GB/T3279-89) This type of hot-rolled sheet is mainly used to manufacture leaf springs, disc springs and other components of machinery and vehicles. e. Carbon tool steel hot-rolled sheet (GB/T3278-82) This type of hot-rolled sheet is mainly used to manufacture cutting tools, measuring tools, molds and other tools with low cutting speed, simple shape and low precision requirements. f. Stainless steel hot-rolled sheet (GB/T4237-92) Stainless steel has excellent corrosion resistance, this type of hot-rolled sheet is widely used in aviation, petroleum, chemical, textile, food, medical equipment and other components requiring corrosion resistance, Containers, mechanical parts, etc. In addition to the above hot-rolled sheets, there are also some special-purpose hot-rolled sheets, such as: high-quality carbon structural steel hot-rolled sheet for automobile manufacturing (GB/T3275-91) 81) Hot-rolled steel sheet for welded gas cylinders (GB/T6653-94) Hot-rolled steel sheet for compressor valve plates (GB/T11254-94) Hot-rolled patterned steel sheet (GB/T3277-91) For 200-liter oil drums Hot rolled carbon structural steel sheet (YB/T5037-93). Cold-rolled sheet Cold-rolled sheet has good performance, that is, through cold rolling, cold-rolled strip and steel sheet with thinner thickness and higher precision can be obtained, with high flatness, high surface finish, clean and bright surface of cold-rolled sheet, easy to use Coating processing, many varieties, wide range of uses, and at the same time have the characteristics of high stamping performance, no aging, low yield point, so cold-rolled sheets have a wide range of uses, mainly used in automobiles, printed iron drums, construction, building materials, bicycles It is also the best choice for the production of organic coated steel sheets. Galvanized steel sheet 1. Function Galvanized steel sheet is to prevent the surface of the steel sheet from being corroded and prolong its service life. The surface of the steel sheet is coated with a layer of metal zinc, which is called galvanized sheet. 2. Classification According to the production and processing methods, it can be divided into the following categories: ① Hot-dip galvanized steel sheet. The sheet steel is immersed in a molten zinc bath, and a sheet of zinc is adhered to its surface. At present, it is mainly produced by continuous galvanizing process, that is, galvanized steel plate is made by continuously immersing the rolled steel plate in a plating tank with molten zinc; ② Alloy galvanized steel plate. This kind of steel plate is also manufactured by hot dip method, but immediately after being out of the tank, it is heated to about 500 ℃ to form an alloy coating of zinc and iron. This galvanized sheet has good paint adhesion and weldability; ③Electro-galvanized steel sheet. The galvanized steel sheet produced by the electroplating method has good workability. However, the coating is thin, and the corrosion resistance is not as good as that of the hot-dip galvanized sheet; ④Single-sided and double-sided poor galvanized steel. Single-sided galvanized steel sheet, that is, a product that is galvanized on only one side. In welding, painting, anti-rust treatment, processing, etc., it has better adaptability than double-sided galvanized sheet. In order to overcome the shortcoming of uncoated zinc on one side, there is another galvanized sheet coated with a thin layer of zinc on the other side, that is, double-sided differential galvanized sheet; ⑤Alloy and composite galvanized steel sheet. It is made of zinc and other metals such as lead and zinc to make alloys and even composite plated steel sheets. This kind of steel plate has both excellent anti-rust properties and good coating properties. In addition to the above five kinds, there are also color galvanized steel sheet, printed coated galvanized steel sheet, PVC laminated galvanized steel sheet, etc. But the most commonly used is still hot-dip galvanized sheet. Main production plants and import production countries: ① Main domestic production plants: Wuhan Iron and Steel, Anshan Iron and Steel, Baosteel and Xi’an Hongtong Steel Co., Ltd., etc.; ② Major foreign producers are Japan, Germany, Russia, France, South Korea, etc. 3. Dimensions and specifications The relevant product standards all list the recommended standard thickness, length and width of galvanized sheets and their allowable deviations. The thickness deviation is generally 0.05mm, the length and width deviation is generally 5mm, and the thickness of the plate is generally between 0.4-3.2. Please refer to the relevant product standards provided in “8” in this section. 4. Appearance (1) Surface condition: Due to the different treatment methods in the coating process, the surface condition of the galvanized sheet is also different, such as ordinary spangle, fine spangle, flat spangle, no spangle and phosphating surface. German standards also specify surface grades. (2) The galvanized sheet should have a good appearance, and there should be no defects that are harmful to the use of the product, such as no plating, holes, cracks and scum, over-plating thickness, scratches, chromic acid dirt, white rust, etc. Foreign standards are not very clear about specific appearance defects. Some specific defects should be listed in the contract when ordering. 5. Galvanizing amount (1) Standard value of galvanizing amount: galvanizing amount is a commonly used and effective method to express the thickness of zinc layer of galvanized sheet. The unit of galvanizing amount is g/m2. See Table 6-7-4 for the stipulations on the galvanized amount of galvanized sheet in Japanese, American and German standards. (2) Measurement method: see the relevant standards in “8” for sampling requirements and test methods. 6. Mechanical properties (1) Tensile test: Table 6-7-4 Index of galvanized sheet steel (unit: g/m2) 500 600 ASTMA525 code A40 A60 G165 G90 G115 G140 G165 G185 G210 galvanized amount 122 183 183 275 351 427 503 564 640 DIN1716 code 100 200 275 350 450 600 galvanized amount 100 200 275 350 450 600 1 Performance indicator: Generally, Only structural, tensile and deep drawing galvanized sheets have tensile properties requirements. Among them, the galvanized sheet for structural use requires yield point, tensile strength and elongation, etc.; for tensile use, only elongation is required. For specific values, see the relevant product standards in “8” of this section; ② Test method: the same as the test method for general thin steel plates, see the relevant standards provided in “8” and the test method standards listed in “Ordinary Carbon Steel Thin Plates”. (2) Bending test: Bending test is the main item to measure the technical performance of thin plates, but the requirements of various national standards for various galvanized sheets are not consistent. Except for structural grades, the American standards do not require bending and tensile tests. In Japan, except for structural grade, building corrugated board and general corrugated board, bending test is required. ①Requirements: Generally, after the galvanized sheet is bent by 180°, the outer surface of the galvanized sheet must not be separated from the zinc layer, and the plate base must not be cracked or broken; For the ratio of the inner space to the thickness of the test sample, see the relevant product standards listed in “8”. Seven, chemical composition The requirements for the chemical composition of galvanized sheet substrates are different in various countries. For example, Japan does not require it, but the United States requires it. Generally not for finished product inspection. Eight, packaging It is divided into two kinds of galvanized sheet cut to length and coiled galvanized sheet. It is generally packed in iron sheet, lined with moisture-proof paper, and tied on the bracket with an iron waist. The binding should be firm to prevent the galvanized sheets from rubbing against each other. 9. Main foreign standards on galvanized sheet (1) Product standard: JIS G3302-94 galvanized steel sheet; JIS G3312-94 painted galvanized iron sheet; JIS G3313-90 (96) electro-galvanized steel sheet and strip; General requirements for galvanized steel sheet; ASTM A526-90 commercial grade hot-dip galvanized steel sheet; ASTMA 527-90 (75) clinching grade hot-dip galvanized steel sheet; ASTMA528-90 deep-drawing grade hot-dip galvanized steel sheet; roofing and Hot-dip galvanized sheet for siding; ASTMA444-89 hot-dip galvanized sheet for trenches; ASTM A446-9 3 structural grade hot-dip galvanized sheet; ASTMA599-92 cold-rolled electro-galvanized sheet; ASTMA642-90 hot-dip galvanized sheet Special deoxidized deep drawing grade sheet; ΓOCT7118-78 galvanized sheet; DINEN10142-91 part 1 low carbon steel hot-dip galvanized steel strip and sheet; DINEN1012-92 part 2 hot-dip galvanized sheet. (2) Test method standards: JIS H0401-83 hot-dip galvanizing test method; DIN50952-69 hot-dip galvanizing test method. *Uses, technical indicators, performance and specifications of galvanized sheet products Galvanized sheet steel products are mainly used in construction, light industry, automobiles, agriculture, animal husbandry, fishery and commercial industries. Among them, the construction industry is mainly used to manufacture anti-corrosion industrial and civil building roof panels, roof grilles, etc.; the light industry 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 for cars, etc. ; Agriculture, animal husbandry and fishery are mainly used for food storage and transportation, meat and aquatic products freezing processing tools, etc.; Galvanized sheet technical index, performance, specification list (Z) Zinc spangle obtained by condensing the zinc layer under normal conditions after galvanizing General purpose Smoothing spangle (GZ) The zinc spangle on the surface of the galvanized sheet is smoothed by the finishing machine to smooth the spangle on the surface of the galvanized plate The substrate used as the color-coated sheet uses the medium-width galvanized sheet Processability Yield strength Tensile strength Elongation% 180o Cold bending workability Yield strength Tensile strength Elongation% 180o Cold-formed ordinary PV — 270－500 — d= 0, good, not dezincified deep drawing SC — 270-380 ≥30 d=0, good, not dezincified mechanical bite JY — 270-500 — d=0, good, not dezincified super deep drawing SC — 270-380 ≥30 d=0, intact, not dezincified structure JG ≥240 ≥370 ≥18 d=0, intact, not dezincified — — — — — X. Development status of galvanized sheet in my country 1. Domestic galvanized sheet market overview and production and consumption situation Plate consumption is about 5.27 million tons. After 1999, the import volume of galvanized sheet exceeded the production volume for the first time, the self-sufficiency rate of domestic products was less than 50%, and there was a trend of decreasing year by year. (1) Current situation of production and consumption of hot-dip galvanized sheet The import volume increased faster, from 370,000 tons in 1998 to 1.56 million tons in 2002; the apparent consumption increased from 1.32 million tons to 3.67 million tons. In 2002, the domestic product self-sufficiency rate of hot-dip galvanized sheet was about 60%. The domestic production and import of hot-dip galvanized sheet increased compared with the previous year, especially the increase in import volume, mainly due to the supply of hot-dip galvanized sheets. The increase in demand for thin-gauge hot-dip galvanized sheets for the production of color-coated sheets has led to a decline in the self-sufficiency rate of domestic products. (2) Status of production and consumption of electro-galvanized sheet quick. At present, the production scale of electro-galvanized sheet in my country cannot meet the needs of the domestic market in terms of quantity, variety and quality. From 1998 to 2002, the domestic production of electro-galvanized sheet grew slowly, from 170,000 tons to 400,000 tons; while the import volume increased rapidly, from 730,000 tons to 1.78 million tons; the apparent consumption increased from 870,000 tons to 2.16 million tons. The self-sufficiency rate of domestic products is less than 20%. 2. Import analysis of galvanized sheet The increase in domestic consumption of galvanized sheet is mainly driven by imports. In recent years, the import volume of galvanized sheet has increased year by year, and the imported varieties are mainly electro-galvanized sheet, but the proportion of imported electro-galvanized sheet is decreasing year by year; correspondingly, the import proportion of hot-dip galvanized sheet is increasing year by year. In 2003, my country’s imports of hot-dip galvanized sheet exceeded that of electro-galvanized sheet for the first time.
Sino East Steel Enterprise Co., Ltd. as a leading China steel products manufacturer specialized in production of high quality steel series products and located in Tianjin. The area of Sino East Steel Group is about 60,000 square meters with annual steel production capacity reaching to 500,000 MT. Its products’ ranges include steel pipes, tubes, steel sheet and coil, structural steel like steel profile and so on.