Hot Rolling VS Cold Rolling

hot rolling

Hot Rolling VS Cold Rolling

What are the differences between hot rolling and cold rolling? 

This is also a matter of concern. Although they are all rolled, they are still very different and applicable to different situations. 

Therefore, it is necessary to analyze and introduce them in detail so that we can distinguish and use hot rolling and cold rolling. The specific analysis is as follows.

The hot-rolled plate has low hardness, easy processing, and good ductility.

The cold-rolled sheet has high hardness and relatively difficult processing, but it is not easy to deform and has high strength.

The hot rolled plate has relatively low strength and poor surface quality, but good plasticity. It is generally a medium and thick plate. Cold-rolled plate: it has high strength, high hardness, and a high surface finish. It is generally a thin plate and can be used as a stamping plate. The mechanical properties of hot-rolled steel plate are far inferior to cold working and forging, but it has better toughness and ductility.

The cold-rolled steel plate has a certain degree of work hardening and low toughness, but it can achieve a good yield strength ratio. It is used for cold bending springs 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.

Or by definition, the ingot or billet is difficult to deform and process at room temperature. Generally, it is heated to 1100-1250 ℃ for rolling. This rolling process is called hot rolling. However, because the surface of the steel is easy to form iron oxide scale at high temperature, which makes the surface of hot-rolled steel rough and the size fluctuates greatly, the steel with smooth surface, good size, and mechanical properties are required to be produced by cold rolling with hot-rolled semi-finished products or finished products as raw materials.

Rolling at normal temperature is generally understood as cold rolling. From the point of view of metallography, the boundary between cold rolling and hot rolling should be distinguished by recrystallization temperature. That is, the rolling below the recrystallization temperature is cold rolling, and the rolling above the recrystallization temperature is hot rolling. The recrystallization temperature of steel is 450-600 ℃.

From the aspect of characteristics: the temperature of the hot-rolled workpiece is high, so the deformation resistance is small, and large deformation can be realized. Taking the rolling of steel plate as an example, the thickness of continuous casting slab is generally about 230mm, while after rough rolling and finish rolling, the final thickness is 1-20mm. At the same time, because the width thickness ratio of the steel plate is small and the requirements for dimensional accuracy are relatively low, the shape problem is not easy to occur, and the convexity is mainly controlled. The requirements for microstructure are generally realized by controlled rolling and cooling, that is, the microstructure and mechanical properties of the strip are controlled by controlling the start rolling temperature, final rolling temperature, and crimp temperature of finish rolling.

Cold rolling generally has no heating process before rolling. However, due to the small thickness of strip steel, it is easy to have flatness problems. Moreover, after cold rolling, it is the finished product. Therefore, in order to control the dimensional accuracy and surface quality of strip steel, many cumbersome processes are adopted. Cold rolling has a long production line, many equipment, and complex process. Moreover, the temperature of roll and strip steel is also an important control index. Cold-rolled products and hot-rolled products are the difference between the previous process and the next process.

cold rolling


Please contact stella@hanrm.com for a quotation.
And free send inquiry to us.
Email: stella@hanrm.com   stellarollingmill@gmail.com
Whatsapp/Wechat:+8615877652925

hot rolling

位置： 4683-4769 509، As Sulimaniyah, Riyadh 12243沙烏地阿拉伯
We are the manufacturer of Steel Rolling mills, Wire Rod Mills, TMT Rebar Mills, Electric Arc Furnaces, Flying shears, Continuous Casting machines, and spare parts. we can supply designing, manufacturing, installation and commissioning of the equipment with "turn-key" service. We can also design, manufacture and revamp other non-standard equipment according to the requirements of users. Free mail to Stella@hanrm.com for your rolling mill plant Solution  Whatsapp/Wechat:+8615877652925 https://www.hanrm.com/ https://www.electricarcfurnaces.com/ https://www.hanmetallurgy.com/ https://www.rollingmillmachine.com/

评论

发表评论

此博客中的热门博文

Technical Specification for Bar Mill Walking Beam Cooling Bed

图片
Technical Specification for Bar Mill Walking Beam Cooling Bed 1. Service Environment and Conditions of Equipment Ambient temperature: - 20 - + 40 ℃ relative humidity: Working environment: not applicable to inflammable and explosive altitude: + 108 M 2. Technical Requirements 2.1 Incoming direction: left feeding, see the document library of equipment layout plan in the cooling bed area 1 - finished rolling mill 2 - finished flying shear 3 - acceleration roller table 4 - step cooling bed 5 - cold shear 6 - sizing machine 2.2 Technical Parameters 2.2.1 Acceleration Roller Table Roll Diameter: Φ 188mm, roll length: 190mm, roll distance: 1200mm, transmission type: single machine transmission, variable frequency speed regulation, irreversible; roller linear speed: 4.5 ~ 20m / s, roller length: ~ 30000mm, motor: yvpg100l2-4, 2.2kW, 1500rpm, AC380V, axial flow fan at the end of each motor: 125fzy2-s, 25W, 220V, 50Hz, the last six rollers are installed at an inclination of 1 ° ~ 12 °. Q
Read more »

500000 TPY Rebar Rolling Mill For Sale

图片
500000 TPY Rebar Rolling Mill For Sale Our company is revamping a complete set of bar rolling mill equipment with an annual output of 500,000 tons. The whole rebar mill line includes: walking bean reheating furnace, roughing mill stands,  intermediate rolling mill stands, finishing mill stands, cold shear, flying shear, walking beam cooling bed. Annual output capacity:  500.000 Metric Tons rebar Per Year Dimensions: 330 meters x 23 meters Raw material size: 160 x 160 mm Billets Product Size: 10-51 mm rebar Product Length: 6- 12 Meters Bundle Weight 2,1 Ton The Rebar Rolling Mill Consists of: 90 TPH Walking Beam Reheating Furnace Pinch Roll Roughing Mill Stands  Crop Shear No. 1 Intermediate Mill Stands  Crop Shear No.2 Finishing Mill Stands Quenching and Self- Tempering of Bars, (QBT System) Dividing Shear Cooling Bed + Test Sample Inspection Cold Shear Collecting Station Bar Counting SUND BARISTA Bundling & Binding Weight Cell Tag St
Read more »

The Difference between Two-high Rolling Mill and Four-high Rolling Mill

图片
The difference between Two-high Rolling Mill and Four-high Rolling Mill Many friends do not know what is a four-roll mill. In fact, the four-roll mill is a combination of two working rolls and two supporting rolls. It belongs not only to the driving machine of backup rolls but also to the equipment driven by working rolls. Therefore, the specific choice should be made according to the requirements of customers, and also to the actual use situation. What is the difference between a two-roll mill and a four-roll mill? For a two-roll mill, the whole diameter of the roll is relatively large, and the contact area between the roll and the tie piece is also very large, so the whole rolling force is relatively large, so there are certain requirements for the selection of rolling materials and thickness, so as to effectively avoid many unnecessary problems in the whole rolling process. Four-high rolling mill also increases in roll system, so its working roll diameter can be much small
Read more »

Hot Rolling Mill: 50,000 -300,000 TPY of Bar Rolling Mill

图片
Full Continuous Rolling 50,000 -300,000 TPY of Bar Rolling Mill Production Line. Finished bar size: 8-32mm Raw Material: common carbon steel, high-quality carbon structural steel, and low alloy steel The designed annual production capacity is 50,000 -300,000 tons. The maximum rolling speed of finishing mill is 5-16 m/s. 1. Billet The whole continuous rolling production line uses 100 x 100-150 x 150 continuous casting billet as raw material, with a length of 3000 mm-6000 mm, all provided by the company's internal steelmaking and continuous casting workshop. 2. A new regenerative push-steel reheating furnace is built in the full tandem rolling production line. The fuel is natural gas or blast furnace gas, and the air is preheated singly. The hourly heating capacity is 40-80 t/h, end-in, and side-out, single-row material distribution, meeting the annual production requirements of 50,000 -300,000 tons of rolling. Reheating furnace chamber size 6.6X24m. 3. Sixteen
Read more »

Sendzimir 20 High Mill

图片
  Sendzimir 20 High Mill The essential difference between Sendzimir cold rolling mill and four high rolling mill or other types of rolling mill is the different transmission direction of rolling force. The rolling force of the Sendzimir cold rolling mill is transferred from the work roll to the backup roll device through the intermediate roll, and finally to the solid overall stand. This design ensures the support of the work roll in the whole length direction. In this way, the roll system deformation is very small, and the very accurate thickness deviation can be obtained in the whole width direction of rolling. Sendzimir mill has the following main characteristics in structure and performance (1) The frame with integral casting (or forging) has high rigidity, and the rolling force acts radially on each section of the frame. (2) The work roll diameter is small, and the pass reduction rate is large, up to 60%. Some materials can be rolled into very thin strips without intermediate anne
Read more »

Difference Between Hot Rolled and Cold Rolled Stainless Steel

图片
Difference Between Hot Rolled and Cold Rolled Stainless Steel Both hot rolling and cold rolling are processes for forming section steel or steel plate. They have a great influence on the structure and properties of Bai steel. The rolling of steel is mainly hot rolling, and cold rolling is only used to produce small section steels and thin plates.  Hot Rolling Advantages :  It can destroy the casting structure of the steel ingot, refine the grain of the steel, and eliminate the defects of the microstructure so that the steel structure is dense and the mechanical properties are improved. This improvement is mainly reflected in the rolling direction so that the steel is no longer isotropic to a certain extent; bubbles, cracks, and looseness formed during casting can also be welded under high temperature and pressure. Disadvantages:  1. After hot rolling, the non-metallic inclusions (mainly sulfides and oxides, as well as silicates) inside the steel are pressed into thin sheets, and delami
Read more »

How to Choose the Right Nodulizer?

图片
How to Choose the Right Nodulizer? (Summary description)Spheroidizing agents can promote graphite crystallization in nodular cast iron into spherical additives. General application field, cast iron casting field. However, there are many types and contents of spheroidizing agents on the market. Therefore, it is also imperative to choose a suitable spheroidizing agent. Spheroidizing agents can promote graphite crystallization in nodular cast iron into spherical additives. General application field, cast iron casting field. However, there are many types and contents of spheroidizing agents on the market. Therefore, it is also essential to choose a suitable spheroidizing agent. There are data from the reaction thermodynamics of spheroidizing elements in molten iron, reaction kinetics, quality influencing factors in the production process of spheroidizing agent, and process influencing factors in the use process of foundries. The standards for determining the quality of spheroidizing agent
Read more »

Hot Rolling Process

图片
Hot Rolling Process The semi-finished billet from the steelmaking plant is rolled to make it a qualified product. Introduction of Hot Rolling Process Process Flow of Hot Rolling: Process Flow of Main Rolling Line: The slab is directly sent to the slab warehouse of the hot rolling workshop from the slab discharging roller table of the continuous caster in the steelmaking and continuous casting workshop, and the directly hot charged slab is sent to the furnace loading roller table of the heating furnace for heating. The slab that cannot be directly hot charged is lifted into the insulation pit by the crane, then lifted to the upper material bench by the crane after insulation, and then heated by the furnace loading roller table of the heating furnace, leaving the possibility of direct rolling. The continuous casting slab is transported into the slab warehouse by the continuous casting workshop through the slab loading roller table or slab unloading roller table. Before the slab reaches t
Read more »

Introduction of Rolling Mill Categories

图片
Introduction to the Performance of Common Rolling Mill Categories At present, there are many types of rolling mills in the market, which can be divided according to the arrangement and number of rolls. One kind of two-roll mill is simple in structure and widely used. It can be further divided into reversible and irreversible. Comparatively speaking, the working roll diameter of the four-bar mill is smaller, the rolling moment is transferred, and the rolling pressure is borne by the backup roll with a larger diameter. The main advantages of this kind of equipment are large relative stiffness, large reduction, small rolling ductility, and the ability to roll thinner plates, including reversible and continuous rolling. The five-roll mill consists of two structural forms, one is a contact-bending-straightening mill. In fact, the equipment belongs to a four-high mill with small diameter idle rolls that bend the rolled parts, and its reduction is many times larger than that of o
Read more »

Limit Heating Process System of Rolling Reheating Furnace

图片
The ultimate heating process system of rolling reheating furnaces is based on the design idea that the higher the production, the better the quality of heating. The essence of the limit heating process system is to determine the heating process based on the improvement of the production efficiency of the reheating furnace .  Therefore, according to the design of the reheating furnace according to the ultimate healing process of reheating furnace, there will be no allowable limit value of heating defects when the furnace temperature is set, and the furnace outlet temperature is set to the highest possible level, so as to realize the ultimate heating speed of reheating furnace for billet and make the ultimate level of unit production efficiency fully play. Based on the limit heating process system, the heating speed, unit productivity and furnace temperature of the furnace are all in the limit condition, so it is called the limit heating process system. 　　 The advantage of the lim
Read more »