(1) cold rolled steel plate due to a certain degree of work hardening, toughness is low, but can achieve a better flexural strength ratio, used for cold bending spring sheet and other parts.
(2) cold plate using cold rolled surface without oxidized skin, good quality. Hot rolled steel plate using hot rolled processing surface oxide skin, plate thickness has under the difference.
(3) hot rolled steel plate toughness and surface flatness is poor, the price is lower, while the cold rolled plate stretching good, toughness, but more expensive.
(4) rolling is divided into cold rolled and hot rolled steel plate, with the recrystallization temperature as the point of differentiation.
(5) Cold rolling: cold rolling is generally used in the production of strip, its rolling speed is higher. Hot rolled steel plate: the temperature of hot rolling is similar to that of forging.
(6) The surface of hot rolled steel plate without plating becomes blackish brown, the surface of cold rolled steel plate without plating is gray, and after plating, it can be distinguished from the smoothness of the surface, which is higher than that of hot rolled steel plate.
Definition of hot rolled steel strip
Hot-rolled strip width less than or equal to 600mm, thickness of 0.35-200mm steel plate and thickness of 1.2-25mm steel strip.
Hot Rolled Strip Market Positioning and Development Direction
Hot rolled strip steel is one of the main varieties of steel products, widely used in industry, agriculture, transportation and construction, and at the same time as a cold rolled, welded pipe, cold formed steel and other raw materials for the production of its output in China's annual output of steel in the total amount of a larger proportion of the dominant role in the production of rolled steel.
In industrially developed countries, hot rolled plate and strip steel accounted for about 80% of the total output of plate and strip steel, accounting for more than 50% of the total steel production, and in the international market competition in the leading position.
In China, the general hot-rolled strip steel products, the lower limit of the thickness of 1.8mm, but in fact, very few manufacturers currently produce hot-rolled strip steel with a thickness of less than 2.0mm, even if the narrow strip, the thickness of the product is generally greater than 2.5mm.
Therefore, a considerable part of the hope that the thickness of less than 2mm strip as raw material users, have to use cold rolled strip.
Cold Rolled Strip
Cold rolled steel strip: metal in the recrystallization temperature below the rolling deformation is called cold rolled, generally refers to the strip is not heated and at room temperature direct rolling process. Cold rolled strip may be hot to the touch, but it is still called cold rolled.
Cold rolled production can provide a large number of high-precision and excellent performance of steel plate and strip, its most important feature is the low processing temperature, compared with the hot rolling production, it has the following advantages:
(1) Cold rolled strip products are accurate in size and uniform in thickness, and the difference in strip thickness is generally no more than 0.01-0.03mm or less, which can fully meet the requirements of high-precision tolerances.
(2) Very thin strips that cannot be produced by hot rolling can be obtained (the thinnest can be up to 0.001mm or less).
(3) The surface quality of cold rolled products is superior, there is no hot rolled strip often appearing pitting, pressed into the iron oxide and other defects, and can be produced according to the user's requirements of different surface roughness of the strip (glossy surface or pitted surface, etc.), in order to facilitate the processing of the next process.
(4) Cold rolled strip steel has very good mechanical properties and process properties (such as higher strength, lower yield limit, good deep drawing performance, etc.).
(5) High-speed rolling and full continuous rolling can be realized, with high productivity.
Cold rolled strip steel classification
Cold rolled strip steel is divided into two kinds: black and bright.
(1) black annealed strip: cold rolled strip directly heated to the annealing temperature, the surface color due to high temperature exposure to air black. Physical properties become soft, generally used for steel strip and then extended pressure, stamping, deformation of the larger deep processing.
(2) bright annealed strip: and black annealed the biggest difference is that the heating is not in contact with air, with nitrogen and other inert gases have been protected, the surface color to maintain and cold rolled strip, in addition to the black annealed use is also used for the surface of the surface of nickel plating and other surface treatments, beautiful and generous.
Bright strip steel and black fading strip steel difference: mechanical properties are almost the same, bright strip steel is in the black fading strip steel on the basis of more than one step of bright treatment.
Usage: black fading strip steel is generally made into end products before good to do some landscaping treatment, bright strip steel can be directly stamped into end products.
Cold rolled steel production development overview
Cold rolled strip production technology is an important symbol of the level of development of the steel industry. Thin steel plate for automobile, agricultural machinery, chemical industry, food canning, construction, electrical appliances and other industrial use, but also has a direct relationship with daily life, such as household refrigerators, washing machines, televisions and other needs of thin steel plate. Thus, in some industrially developed countries, thin steel plate accounted for the proportion of steel increases year by year, in the thin plate, strip steel, cold rolled products account for a large part.
Post time: Mar-06-2024
