With the maturity of new control technologies such as dimensional accuracy, shape and surface quality of hot rolling and the emergence of new products, hot rolled steel plates and strips have been widely used and become more and more competitive in the market. Hot rolled steel plate products include steel strip (coil) and steel plate cut from it. Steel strip (coil) can be divided into straight hair coil and finishing coil (divided coil, flat coil and longitudinal shear coil).
Available brands, supply standards, use standards and national standards of brands are equivalent to foreign standards. The function and use of materials are bound by standards. The standard quantity of the brand is suitable for manufacturing cold-formed parts. Low carbon steel coil q/bkb302 SPHCJISG 3131SPHCSPD SPHE SPHE SAE1006/SAE1008 SAE1006/SAE1008 XG/ Kloc-0/80IF/200IFXG180IF+080IF/200IF General structural steel GB/t 9 108 General structure Q235B ss 400 ss 400 ss 490 x90 ss 540 size, total weight and allowable deviation thickness (mm) width (mm) Coil inner diameter (mm)1.5 ~ 4.0800 ~1600 2000 ~ 2500 (or c) φ 580.
Table 2 Nominal thickness after slicing (mm) Thickness tolerance (mm) Width direction
Thickness deviation in rolling direction after slicing (mm)
Thickness deviation (mm) >1.5-2.60.10 ≤ 0.05 ≤ 0.05 > 2.6-3.0 0. 12≤0.05≤0.05 & gt； 3.0-4.0-0.17 ~+0.12 ≤ 0.05 ≤ 0.051.3 The roughness of steel plate shall not be greater than 12 mm, and the unit length of roughness measurement shall be1000 mm.
1.4 The sickle bend of steel plate and steel strip shall not be greater than 4mm every 2 meters.
1.5 the width tolerance of steel plate and steel strip shall comply with the provisions in the following table. Width allowable deviation (mm) thickness range (mm) >: 2.0-2.8 > 2.8-3.5 Trim 0~+3 0~+5 without deduction of +20 (target value+10) 1.6 The head and tail overflow edge of steel coil shall not be greater than 40mm, and the middle overflow edge and tower height shall not be greater than 30mm.
1.7 The weight of each roll should be 5-25 tons.
Mechanical properties nominal thickness yield strength (Mpa) tensile strength (Mpa) elongation A50mm% 180 degree bending test >:1.5-2.5 ≤ 290 ≥ 310 ≥ 38d = 0a > 2.5-3.0≤290≥300≥38d = 0a & gt； 3.0-4.0 ≤ 290 ≥ 300 ≥ 40d = 1/2a Description:1. The tensile test and bending test listed in the table are applicable to longitudinal specimens.
2. The tensile test adopts samples with L0 = 50mm and B = 25mm.
3. The sampling scheme of bending test is carried out according to No.3 sample in JIS Z 2204, and the test method is carried out according to JIS Z 2248.
4. Hardness test shall be conducted in accordance with JIS Z 2245.
5. The target value of 5.HRB hardness is 60 8. The actual value is provided in the warranty, but it is not required for acceptance.
3.3 Surface quality
3.3. 1 inclusions, cracks, rust and other defects harmful to use are not allowed on the surface of steel plate or steel strip, and parking spots are not allowed. Defects that do not affect the molding performance are allowed, such as slight scratches without hand feeling, light yellow film after pickling, slight pits, scratches, roll marks and indentations, color difference and slight wrinkles without hand feeling.
3.3.2 As the steel strip has no chance to eliminate defects, delivery with defects is allowed, but the defective part shall not exceed 6% of the total length of steel coil.
3.3.3 Oiling refers to coating the surface of steel plate with electrostatic antirust oil with certain antirust performance. Oil injection is divided into light oil injection, medium oil injection and heavy oil injection, which are stipulated by the buyer in the contract. Under normal transportation and storage conditions, the supplier shall ensure that the oiled products will not rust within 3 months. Hot continuous rolling can be divided into ordinary carbon structural steel, low alloy steel and alloy steel according to different materials and properties.
According to different uses, it can be divided into cold-formed steel, structural steel, automobile structural steel, corrosion-resistant structural steel, mechanical structural steel, welding steel for gas cylinders and pressure vessels, pipeline steel and so on. Hot rolled steel products have a wide range of steel specifications and uses, from general engineering structures to the manufacture of automobiles, bridges, ships, boilers and pressure vessels. Different uses have different requirements for material properties, surface quality, size and shape accuracy of steel plates. Therefore, it is necessary to know the varieties, materials, characteristics and uses of hot rolled steel plates in order to achieve economic and reasonable utilization.
Hot rolling application industry
Hot rolling is mainly used in petrochemical equipment, automobile industry, agricultural vehicle industry, shipbuilding industry, iron tower industry, steel structure industry, power equipment, lamp pole industry, telecom iron tower, spiral steel pipe industry, metal stamping parts, transportation facilities industry, craft boat, wheel manufacturing industry, pressure vessel, boiler, steel formwork industry, crane, environmental protection machinery, textile machinery, container, safe, dust removal equipment, flour and so on. Steel mesh factory, brake pad in automobile industry, mining machinery, cold rolled strip steel mill, fan factory, shelf, barrel making industry, lighting equipment, agricultural machinery, harvester, cold-formed steel, installation company, etc.