What is cold rolled steel plate

What is cold rolled steel plate?

Cold rolling is made by rolling hot rolled coil under recrystallization temperature at room temperature. Cold rolled steel plate is the steel plate produced by cold rolling process, which is referred to as cold plate for short. The thickness of cold-rolled sheet is generally between 0.1-8.0mm. The thickness of cold-rolled sheet produced by most factories is less than 4.5mm. The thickness and width of cold-rolled sheet are determined according to the equipment capacity and market demand of each factory.

Difference between hot rolled and cold rolled

Hot-rolling

Hot rolling is to take slab (mainly continuous casting slab) as raw material and make strip steel by roughing mill and finishing mill after heating. The hot steel strip from the last finishing mill is cooled to the set temperature through laminar flow, and then rolled into steel strip coil by coiler. The cooled steel strip coil is processed into steel plate, flat coil and slitting steel strip products through different finishing operation lines (leveling, straightening, cross cutting or longitudinal cutting, inspection, weighing, packaging and marking, etc.) according to the different needs of users. To put it simply, a billet is heated (that is, the red hot steel block in TV) and rolled several times, then trimmed and corrected into a steel plate. This is called hot rolling.

Cold rolling

Cold rolling: hot rolled steel coil is used as raw material for cold continuous rolling after acid pickling to remove oxide scale. The finished product is hard rolled coil. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of hard rolled coil increase and the toughness and plasticity index decrease. Therefore, the stamping performance will deteriorate and can only be used for simple deformed parts. The hard rolled coil can be used as the raw material of the hot-dip galvanizing plant, because the hot-dip galvanizing units are equipped with annealing lines. The weight of rolled hard coil is generally 6 ~ 13.5 tons. The hot-rolled pickling coil is continuously rolled at room temperature. The inner diameter is 610mm.
Product features: because it has not been annealed, its hardness is very high (HRB greater than 90) and its machining performance is very poor. It can only carry out simple directional bending less than 90 degrees (perpendicular to the coiling direction).
To put it simply, cold rolling is processed and rolled on the basis of hot rolled coils. Generally speaking, it is a processing process of hot rolling pickling cold rolling.
Cold rolling is processed from hot-rolled plate at room temperature. Although rolling will also raise the temperature of steel plate in the processing process, it is still called cold rolling. Because the cold rolling formed by hot rolling through continuous cold deformation has poor mechanical properties and high hardness. The rolled coil can only recover its mechanical properties after annealing. Rolled coil is generally used to make products without bending and stretching.

Allowable deviation of steel plate width

Cold rolled steel sheet and strip

Nominal width/mm
Allowable deviation of width/mm
≤l000
+6
>1000
+10
Steel strip without cutting longitudinal edges
+15

Allowable width deviation of slitting steel strip

Nominal width/mm
Allowable deviation of width/mm
≤125
>125~250
>250~400
>400~
0.20~0.40
+0.3
+0.6
+1.0
+1.5
>0.40~1.0
+0.5
+0.8
+1.2
+1.5
>1.0~1.8
+0.7
+1.0
+1.5
+2.0
>1.8~3.0
+1.0
+1.3
+1.7
+2.0

Allowable length deviation of cold rolled steel plate

Nominal length/mm
≤2000
>2000
Allowable deviation/mm
+10
+15
Shape of cold rolled steel sheet and strip

Flatness of steel plate and strip per meter
Sickle bend of steel strip
Same plate difference of steel plate
Nominal width/mm
Flatness(mm/m)
≤0.70
>0.70~1.50
>1.50~5.0
≤1000
10
8
6
Within every 2m
Not more than half the thickness tolerance
>1000~1500
12
10
8
>1500~2000
18
15
12
Note: the flatness listed in the table is applicable to steel plates and steel strips whose lower limit of ó B is not greater than 485mpa. For the steel plate and steel strip whose lower limit of ó B is greater than 485mpa but not greater than 585mpa, the maximum flatness is allowed to increase by 30% compared with the specified value in the table. For the steel plate and steel strip whose lower limit of ó B is greater than 585mpa, the maximum flatness is allowed to be 50% higher than the specified value in the table.

Application of cold rolled steel sheet

Cold rolled sheet and strip are widely used, such as automobile manufacturing, electrical products, rolling stock, aviation, precision instruments, food cans, etc. Cold rolled steel sheet is the abbreviation of common carbon structural steel cold rolled plate, also known as cold rolled plate, commonly known as cold plate, which is sometimes mistakenly written as cold rolled plate. Cold plate is a steel plate with a thickness of less than 4mm made of hot-rolled steel strip of ordinary carbon structural steel after further cold rolling. Due to rolling at normal temperature, there is no iron oxide scale. Therefore, the cold plate has good surface quality and high dimensional accuracy. Combined with annealing treatment, its mechanical and process properties are better than hot-rolled steel sheet. It has been gradually used to replace hot-rolled steel sheet in many fields, especially in the field of household appliance manufacturing.

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

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