4mm thick 304 stainless steel plate what is the difference between hot rolled plate and cold rolled

Rolling is divided into cold rolling and hot rolling, and the recrystallization temperature is used as a distinguishing point.

Hot rolled plate: 1Poor toughness and surface flatness,** low;

2.The temperature of hot rolling is similar to that of forging;

3.The hot plate is processed by hot rolling, and the surface has oxide scale, and the thickness of the plate is different.

4.Hot-rolled products** and uses are much wider than cold-rolled;

5.The mechanical properties of hot-rolled steel plate are far inferior to cold working, and are also inferior to forging processing, but they have better toughness and ductility.

6.The surface of the non-plated hot plate is black-brown.

7.It can be distinguished from the smoothness of the surface after plating, and the smoothness of the hot-rolled plate is low.

Cold Rolled Plate: 1Good stretch and toughness, but ** more expensive;

2.There is no oxide scale on the surface of cold rolling, ***;

3.Cold rolling is generally used to produce strips, which have a higher rolling speed;

4.The thickness accuracy of cold rolling is higher than that of hot rolling, mechanical properties, and the surface are above hot rolling;

5.Due to a certain degree of work hardening, cold-rolled steel plate has low toughness, but it can achieve a good yield ratio, and is used for cold-formed spring sheets and other parts;

6.Because the yield point of the cold plate is close to the tensile strength, there is no foresight of the danger during use, and accidents are prone to occur when the load exceeds the allowable load.

7.The surface of the cold rolled plate without plating is gray.

8.The smoothness of the surface of the cold-rolled plate after electroplating is higher than that of the hot-rolled plate.

For details of cold-rolled plates, please refer to Encyclopedia: Cold-rolled plates.

The quality of the board surface is very different, mainly because of the appearance.

2.The feel is different: the cold-rolled plate feels delicate and smooth, and the corners are neat; The hot-rolled plate feels a little rough to the touch, and the corners are a little untidy.

3.The characteristics are different: the cold-rolled plate is hard, and the strength is high, and the production process is complex; The hot-rolled plate has low hardness and good ductility, which is convenient to make.

Stainless steel is stainless steel, and there is no such name as stainless steel cold plate.

2. The reasons for the residual stress of hot-rolled steel and cold-rolled steel are different, so the distribution on the cross-section is also very different. The residual stress distribution on the cross-section of cold-formed thin-walled steel is curved, while the residual stress distribution on the cross-section of hot-drawn or welded steel is thin-film.

3. The free torsional stiffness of hot-rolled steel is higher than that of cold-rolled steel, so the torsional resistance of hot-rolled steel is better than that of cold-rolled steel.

4. The cold plate is processed by cold rolling without oxide scale. The hot plate is processed by hot rolling, and the surface has oxide scale, and the thickness of the plate is different.

2.The cold-rolled steel section style is generally an open cross-section, which makes the free torsional stiffness of the cross-section low. It is easy to torsion when bending, and bending-torsional buckling is easy to occur when compression, and the torsional performance is poor;

Cold rolling: hot rolled steel coil as raw material, cold continuous rolling after pickling to remove the oxide scale, the finished product is rolled hard coil, due to the cold work hardening caused by continuous cold deformation, the strength and hardness of the rolled hard coil rise, and the toughness and plastic index decrease, so the stamping performance will deteriorate, and it can only be used for simple deformation of parts. Rolled hard coils can be used as raw materials for hot-dip galvanizing plants, because hot-dip galvanizing units are provided with annealing lines. The weight of the rolled hard coil is generally 6 tons, and the steel coil is continuously rolled at room temperature for the hot-rolled pickled coil. The inner diameter is 610mm.

Product features: Because it has not been annealed, its hardness is very high (HRB is greater than 90), and the machining performance is extremely poor, and it can only carry out simple directional bending processing of less than 90 degrees (perpendicular to the direction of coiling).

To put it simply, cold rolling is processed and rolled on the basis of hot-rolled coils, generally speaking, it is hot-rolled--- pickled --- cold-rolled.

Hot rolling is made of slabs (mainly continuous casting billets) as raw materials, and after heating, strip steel is made from roughing mills and finishing mills. The hot steel strip from the last rolling mill of finishing is cooled to the set temperature by laminar flow, and then rolled into a steel strip coil by the coiler, and the cooled steel strip coil is processed into a steel plate by different finishing lines (leveling, straightening, cross-cutting or slitting, inspection, weighing, packaging and marking, etc.) according to the different needs of users

Flattening coil and slitting steel strip products. To put it simply, a billet is heated (that is, the kind of red and hot steel in TV) after several rolls, and then cut the edge and corrected into a steel plate, which is called hot rolling.

The production process is different.

Stainless steel hot rolling is rolled above the recrystallization temperature of the metal material, and stainless steel cold rolling refers to the rolling below the recrystallization temperature of the metal material, and each metal material has its own recrystallization temperature.

If the above expression is not easy to understand, it is not very accurate to say that hot rolling is the need to heat the material during or before the rolling process, and it is generally heated to above the recrystallization temperature, such as: more than 1000 degrees, etc.; Cold rolling is the process of rolling steel that does not require the material to be heated, or heated below the recrystallization temperature of the material.

Cold rolling is more than hot rolling in the stainless steel processing process, and it is rolled by a cold rolling mill with hot rolled materials as blanks.

The finished product behaves differently.

The most obvious and simple difference between the two is the superficial one.

Hot-rolled stainless steel is rougher, such as hot-rolled plate, most of the rolling thickness is above and above, compared with cold-rolled products, hot-rolled products often have low dimensional accuracy, relatively poor surface quality compared to cold-rolled, and are not as good as cold-rolled in terms of processing performance such as heat treatment.

Stainless steel cold rolling is formed by cold rolling processing as raw material of hot rolling, the dimensional accuracy of general cold-rolled sheet is higher, the surface quality is better, the post-processing performance is relatively good, the thickness range is basically in the following, the general common thickness range is, although there are also outside the range, but rare.

The cold-rolled steel plate implements the national GB T708-1988 standard.

Cold rolling] Cold rolling is made of hot-rolled coil as raw material, rolled at room temperature below the recrystallization temperature, cold-rolled steel plate is a steel plate produced by the cold-rolling process, referred to as cold plate. The thickness of the cold-rolled plate is generally between, and the thickness of the cold-rolled steel plate produced by most factories is the following, and the thickness and width of the cold-rolled plate are determined according to the equipment capacity and market demand of each factory.

Cold rolling is the process of further thinning a steel plate below the recrystallization temperature at room temperature to a target thickness. Compared with hot-rolled steel plate, cold-rolled steel plate has a more accurate thickness and a smooth and beautiful surface.

There are many types of steel, and from the perspective of production methods, there is a difference between cold rolling and hot rolling, what is the difference between the two?

1. The first difference is manifested in the different processing technology, cold rolling is literally through cold working, hot rolling is through hot processing, and the temperature of crystallization is also different, one is below the crystallization temperature, and the other is pressed above the crystallization temperature.

2. The second difference is that the scope of application is different, if the former is adopted, it can be used in the automotive industry or small household appliances, washing machines, refrigerators, etc., including building materials. Hot-rolled steel is mainly used in steel structures or mechanical parts, including bridge construction.

3. The third difference is performance, the former allows the cross-section to appear curved, but the hot rolling can not appear local surface, and the resulting stress is not the same, and the distribution on the cross-section will be different. The local stress of cold rolling should be bending, and hot rolling should be film type. At the same time, the stiffness is relatively high, and the hot-rolled one is also slightly higher.

Second, what are the classifications of steel?

1. If it is divided according to quality, some are high-quality, some are ordinary types, and some are high-end high-quality types. This is actually divided according to the P element and the S element.

2. If it is divided according to the forming method, some are made by calcination, casting, or cold rolling or hot rolling.

3. If it is divided according to the use, there are many of them, such as the steel and structural steel used in the project, and the low-alloy structural steel is one of the types. In addition, there are special properties of steel, which have the function of heat resistance or wear resistance, and some are not easy to rust and acid resistant.

I conclude: By analyzing the difference between cold-rolled and hot-rolled steel plates, we can understand that their production methods and performance characteristics will be different, so the places where they are used are also completely different.

Difference Between Stainless Steel Cold Rolled Plate and Stainless Steel Hot Rolled Plate:

1. The stainless steel cold-rolled plate is cold-rolled, and there is no oxide scale on the surface. The simple lead stainless steel hot-rolled plate is hot-rolled and processed, with oxide scale on the surface and a lower difference in plate thickness.

2. The toughness and surface flatness of stainless steel hot-rolled plate are poor, and the toughness of stainless steel cold-rolled plate is low, while the stretch of stainless steel cold-rolled plate is good, tough, but it is more expensive.

3. Rolling is divided into cold rolling and hot rolling, and the recrystallization temperature is used as the distinguishing point.

4. Xinzhi cold rolling is generally used to produce strips, its rolling speed is high, and the temperature of hot rolling is similar to the temperature of forging.

5. The surface of the stainless steel hot-rolled plate without electroplating is black-brown, and the surface of the stainless steel cold-rolled plate without electroplating is gray. After electroplating, it can be distinguished by the smoothness of the surface, and the smoothness of cold-rolled plate is higher than that of hot-rolled plate.

Stainless steel plate formation process:

1. The stainless steel plate is cold-rolled and slippery, heat treated, pickled, and then smoothed by the rough surface roller, which is called 2D surface processing, and 2D can be pickled surface or rough surface.

2. After pickling, a large-diameter high-precision polishing roller is used to flatten the amount of small pressure (which can only reduce the roughness a little, but can improve the gloss and straightness) to form a 2B surface processing of stainless steel. <>

Hot rolling is to soften the material into a thin sheet or billet cross-section with a pressure wheel after softening it at a temperature higher than the recrystallization temperature of the alloy, so that the material is deformed, but the physical properties of the material do not change.

Cold rolling is the process of further rolling the material with a pressure wheel at a temperature lower than the alloy recrystallization temperature to recrystallize the material that has been hot-rolled, de-pitting and deoxidizing the process. After repeated cold pressing, recrystallization, annealing, and cold pressing (2 3 times) process, the metal in the material changes (recrystallization) at the molecular level, and the physical properties of the alloy formed change. Therefore, its surface is high, the finish is high, the product size accuracy is high, and the performance and structure of the product can meet some special use requirements, such as electromagnetic properties, deep drawing properties, etc.

Cold rolled strip can be used in automobile manufacturing, electrical products, rolling stock, aviation, precision instruments, food canning, etc. tables, canned food, etc.

The toughness and surface flatness of the hot-rolled plate are poor, and the ** is low; The hot rolling process is rough, and very thin steel cannot be rolled out.

The cold-rolled plate has good stretchability and toughness, but it is more expensive.

To put it simply, rolling below the metal recrystallization temperature can be regarded as cold rolling, and the rolling at the recrystallization temperature is hot rolling, visually, the surface of the cold-rolled strip metal luster is obvious, and the hot rolling is not obvious metal luster, because the iron oxide scale is produced in the hot rolling process!

The single rolling and continuous rolling you said should be reversible rolling and continuous rolling, reversible rolling is rolling back and forth on the rolling mill of a single stand or double stand, and continuous rolling adopts 5-7 stands, without reciprocating back and forth rolling, relatively speaking, the reversible rolling speed is slow, the output is low, suitable for small and medium-sized enterprises, multi-variety production, continuous rolling is suitable for large and medium-sized enterprises to carry out large-scale rolling, but this is not absolute.