Cold rolling rolls and hot rolling rolls have obvious differences in many aspects, and these differences also determine their different uses.
Main Differences
Working environment
|
Cold rolling rolls |
Hot rolling rolls |
| Working at room temperature, the friction between the rolled piece and the rolling roll is large during the rolling process, and the surface finish and dimensional accuracy of the rolling roll are very high. | Working in a high temperature environment, generally have to withstand a high temperature of about 1000℃, and also have to withstand large rolling forces and thermal stress. |
Material requirements
| Cold rolling rolls | Need to have high hardness, high wear resistance, good corrosion resistance and dimensional stability to ensure that good surface quality and accuracy can be maintained during the cold rolling process. Usually alloy tool steel and other materials are used, such as 9Cr2Mo, 9Cr3Mo, etc. |
| Hot rolling rolls | Because they have to withstand high temperatures and large rolling forces, they are required to have good heat resistance, thermal fatigue performance and sufficient strength and toughness. Cast steel, forged steel and other materials are often used, such as 50CrMo, 60CrMnMo, etc. |
Surface treatment
| Cold rolling roller | Hot rolling roller |
| The surface needs to be processed and ground with high precision to achieve extremely low surface roughness. Generally, the surface roughness Ra value can reach 0.1μm - 0.05μm, and some are even higher, to ensure the surface quality of cold-rolled products. | Although there are certain requirements for surface roughness, it is lower than that of cold rolling roller. Usually, the surface roughness Ra value is around 1.6μm - 6.3μm. Generally, quenching, tempering and other heat treatments are performed to improve surface hardness and wear resistance. |
Structural features
| Cold rolling roller | Usually the diameter is relatively small, and the roller body length varies according to different rolling requirements, but it is generally shorter than the roller body length of hot rolling rollers. This is to better control the rolling force and ensure rolling accuracy during the cold rolling process. |
| Hot-rolled rollers | The diameter and roller length are usually larger to adapt to the rolling of large-sized rolled pieces and withstand greater rolling forces. For example, the working roller diameter of some large hot-rolled plate and strip mills can reach more than 1000mm, and the roller length can reach more than 2000mm. |
Service life
| Cold-rolled rollers | Hot-rolled rollers |
| The main failure forms are wear and surface fatigue peeling. Due to the high precision requirements in the cold rolling process, once the roller surface is worn or defective, it may affect the product quality, so its service life is relatively short and requires regular grinding and maintenance. |
Mainly facing problems such as thermal fatigue, wear and fracture. Although the working conditions are harsh, due to the relatively low requirements for surface accuracy, under reasonable use and maintenance conditions, the service life is relatively long. Main uses |
Main Use
Cold-rolled rollers
| Cold-rolled strip production | Used for the rolling of cold-rolled thin plates and strips, such as the production of automotive panels, home appliance plates, stainless steel plates, etc., which can enable the rolled pieces to obtain high-precision dimensions, good plate shapes and smooth surfaces. |
| Cold-rolled foil production | When producing metal foils such as aluminum foil and copper foil, cold rolling rollers can achieve high-precision rolling, ensure the thickness uniformity and surface quality of the foil, and meet the high-quality requirements of the electronics, packaging and other industries for foils. |
Hot-rolled rollers
Hot-rolled strip production: It is a key component of the hot-rolled strip mill, used to roll steel billets into hot-rolled steel plates and strips of various specifications, such as medium and thick plates, hot-rolled coils, etc., which are widely used in construction, machinery, automobile and other industries.
Steel section rolling: When rolling I-beams, channels, angles and other steel sections, the hot rolling rollers use a specific hole design to make the steel billets form steel sections of various shapes and sizes during the rolling process, meeting the needs of building structures and machinery manufacturing and other fields.
Bar rolling: It is used for the production of hot-rolled bars, rolling steel billets into round steel, threaded steel and other bar products of different diameters, which are widely used in construction, mechanical processing and other industries.
