What is hot rolled steel plate

What is hot rolled steel plate?

The continuous casting slab or blooming slab is used as the raw material, heated by the stepping heating furnace and descaled by high-pressure water, and then enters the roughing mill. The roughing material enters the finishing mill after cutting, tailing and then enters the finishing mill for computer-controlled rolling. After the final rolling, it passes through laminar cooling (computer-controlled cooling rate) and coiler to form a straight hair coil. The head and tail of straight hair curl are often tongue shaped and fish tail shaped, with poor accuracy of thickness and width, and there are often defects such as wave shape, hem, tower shape and so on. The coil weight is heavy and the inner diameter of the steel coil is 760mm. After the straight hair coil is processed by head cutting, tail cutting, edge cutting, multi pass straightening, leveling and other finishing lines, it is then cut or rewound to become hot-rolled steel plate, flat hot-rolled steel coil, longitudinal cutting belt and other products. The hot-rolled finishing coil will become hot-rolled pickling coil if the oxide scale is removed by pickling and coated with oil. The product has the trend of partially replacing cold-rolled plate, with moderate price, and is deeply loved by the majority of users.

Types and applications of hot rolled steel plates

1. Structural steel
It is mainly used in the production of steel structures, bridges, ships and vehicles.
2. Weathering steel
Adding special elements (P, Cu, C, etc.) has good corrosion resistance and atmospheric corrosion resistance. It is used in the production of containers and special vehicles, as well as building structures.
3. Steel for automobile structure
High strength steel plates with good stamping and welding properties are used in the production of automobile frame, wheel, etc.
4. Hot rolled special steel
Carbon steel, alloy steel and tool steel for general mechanical structure are used for the production of various mechanical parts after heat treatment engineering.
5. Cold rolled stock
It is used to produce all kinds of cold rolled products, including Cr, GI, color coated plate, etc.
6. Steel plate for steel pipe
With good processability and compressive strength, it is used to produce high-pressure gas pressure vessels filled with LPG, acetylene and various gases with a content of less than 500L.
8. Stainless steel plate
Stainless steel has good corrosion resistance. It is mainly used in food industry, surgical equipment, aerospace, petroleum, chemical and other industries.

Mechanical properties of hot rolled steel plate

Nominal thickness
Yield strength (Mpa)
Tensile strength(Mpa)
Elongation%
180 degree bending test
>1.5-2.5
≤290
≥310
≥38
D=0a
>2.5-3.0
≤290
≥300
≥38
D=0a
>3.0-4.0
≤290
≥300
≥40
D=1/2a

Note:

  • 1. The tensile test and bending test listed in the table are applicable to longitudinal samples
  • 2. L0 = 50 mm, B = 25 mm specimens are used for tensile test
  • 3. The sampling scheme for bending test shall be carried out in accordance with sample No. 3 of JIS Z 2204, and the test method shall be carried out in accordance with JIS Z 2248
  • 4. The hardness test shall be carried out in accordance with JIS Z 2245
  • 5. The target value of hardness HRB is 60 ± 8. The actual value is provided in the warranty, but it is not regarded as the acceptance requirement.

Allowable thickness deviation of steel plate and strip

Nominal thickness (mm)
Thickness tolerance (mm)
Thickness deviation in width direction after slicing (mm)
Thickness deviation in rolling direction after slicing (mm)
>1.5-2.6
±0.10
≤0.05
≤0.05
>2.6-3.0
±0.12
≤0.05
≤0.05
>3.0-4.0
-0.17~+0.12
≤0.05
≤0.05
  • The unevenness of steel plate shall not be greater than 12mm. The unit length of unevenness measurement is 1000mm
  • The sickle bend of steel plate and steel strip shall not be greater than 4mm every 2m.
  • The width tolerance of steel plate and strip shall comply with the provisions in the following table.

Difference between hot rolled steel plate and cold rolled steel plate

The carbon content of hot rolled steel plate can be slightly higher than that of cold rolled steel plate. The density is the same when there is little difference in composition. However, if the composition is very different, such as stainless steel, the density of cold-rolled and hot-rolled steel plates is about 7.9g/cm3. It also depends on the composition. The hot-rolled steel plate has better ductility, and the steel is also under pressure.
Hot rolled steel plates are divided into structural steel, low carbon steel and welded bottle steel. Then find the steel you need according to various steels, and check the density and composition of specific steels.
Hot rolled steel plate has low hardness, easy processing and good ductility.
Cold rolled sheet has high hardness and relatively difficult processing, but it is not easy to deform and has high strength.
Hot rolled steel plate has relatively low strength and poor surface quality (oxidation / low finish), but good plasticity. It is generally medium and thick plate. Cold rolled plate: it has high strength, high hardness and high surface finish. It is generally thin plate, which can be used as stamping plate.
The production process of hot rolled steel plate is different from that of cold rolled steel plate. Hot rolled steel plate is rolled at high temperature, and cold rolled steel plate is rolled at room temperature. Generally speaking, cold-rolled steel plate has better strength and hot-rolled steel plate has better ductility. Generally, the thickness of cold rolling is relatively small, and that of hot rolling can be larger. The surface quality, appearance and dimensional accuracy of cold-rolled steel plate are better than those of hot-rolled steel plate, and its product thickness can be rolled to about 0.18mm, so it is more popular. For product acceptance, professionals can be invited.
The mechanical properties of hot-rolled steel plate are far inferior to cold working and forging, but it has better toughness and ductility.
Cold rolled steel plate has a certain degree of work hardening and low toughness, but can achieve a good yield strength ratio. It is used for cold bending spring sheets and other parts. At the same time, because the yield point is close to the tensile strength, it has no predictability of danger in the process of use, and accidents are easy to occur when the load exceeds the allowable load.

  • 1) The cold plate is cold rolled, and the surface is free of oxide skin, with good quality. Hot rolled steel plate with thick oxide skin and poor surface processing.
  • 2) Hot rolled steel plate has poor toughness and surface flatness, and the price is low, while cold rolled steel plate has good extensibility and toughness, but the price is expensive.
  • 3) Rolling is divided into cold-rolled and hot-rolled steel plates, with recrystallization temperature as the distinguishing point.
  • 4) Cold rolling: cold rolling is generally used to produce strip with high rolling speed. Hot rolled steel plate: hot rolling temperature and forging temperature.
  • 5) The surface of non electroplated hot-rolled steel plate is black brown, and the surface of non electroplated cold-rolled steel plate is gray. After electroplating, it can be distinguished from the smoothness of the surface. The smoothness of cold-rolled steel plate is higher than that of hot-rolled steel plate.

Supplement, cold rolled steel plate 0.3-3.0mm, hot rolled steel plate 2.0.

Source: China Steel Plate Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

Related News

  • * 暂无相关文章
العربيةБългарски简体中文繁體中文DanskNederlandsEnglishFrançaisDeutschBahasa IndonesiaItaliano日本語한국어LatinPortuguêsРусскийEspañolதமிழ்ไทยTürkçe