Roller: Structure of Roll Grinder

The Roller grinder is a special grinder developed on the basis of the cylindrical grinder. According to the weight of the roller, it can be divided into two categories:

1. Movable workpiece bed. It is mainly used for roller grinder with the roller weight ≤ 6 tons.

2. Move the wheel frame. It is mainly used for roll grinder with a weight of more than 6 tons. Regardless of the type of roll grinder, their structure is roughly the same. It mainly consists of the following parts: bed, bedside table, tailstock, bracket, grinding wheel rack, convex (concave) forming mechanism, electrical control equipment, coolant supply and filtering equipment. The main components of the roll grinder are briefly described below.

1. Roll grinder bed. This is the basis of ensuring grinding accuracy. 

(1). the main machine of the workpiece mobile grinder is used to support the fixation of roll, tailstock, bracket and headstock, as well as the guiding function of mobile worktable. The auxiliary bed is used to support the wheel frame, and the longitudinal direction of the wheel frame is fixed. 

(2). The main bed of the mobile grinder with the grinding wheel frame is used to support the grinding wheel frame, and the longitudinal direction of the grinding wheel frame moves back and forth on the grinding wheel frame. His machining accuracy and installation accuracy are very high. The auxiliary bed is used to support the fixation of the roller, tailstock, bracket and headframe. The bed is made of cast iron. In order to keep the high precision of the bed, aging treatment and scraping treatment were carried out after machining. The whole bed is placed on the correct angle which is fixed on the cement foundation. Most of the bed rails are in the form of V-P rails (except hydrostatic rails), which have high guiding accuracy and good rigidity. Bed movement is divided into hydraulic cylinder type (short stroke), gear carrier type, and roller screw type.

2. The headstock is used to drive the rolls, most of which use the multi-stage belt drive to ensure stable driving. A special starting motor is also installed on the heavy roller mill. For small roller mills, there are also gearing with reduction mechanisms, such as turbines or gears. The headstock is driven by the electric motor and can be adjusted steplessly. In order to ensure the smooth rotation of the roll, a floating driving device is set on the dial, and the pressure on the two dial must be evenly applied during the rotation.

3. Tailstock. The function of the tailstock is to position the roll axially during grinding to avoid the mill roll moving axially during grinding. Most tailstock consists of upper and lower parts. The lateral direction can be slightly adjusted from the upper part so that the two shafts of the main axle box are parallel to the main axis. Usually, the diamond finishing pen is mounted on the tailstock to finish the grinding wheel. The tailstock of CNC grinding machine is also equipped with a reference plate, which is used to correct the diameter measured by CNC.

4. Bracket. The carriage is used to support the roll during grinding. It is usually supported on the neck of the roller. It is divided into left and right brackets. The position of the left and right supports and the upper and lower support shoes of each support cannot be reversed. Each support shoe also has a different support diameter to choose from. When adjusting the support seat each time, the upper shoe and lower shoe should be adjusted after the reel is positioned together with the headstock and tailstock by means of lifting equipment.

5. Grinding wheel rack. It is the core of the roll grinder. The formation mechanism of roll shape and spindle which affect grinding accuracy is concentrated on the grinding wheel frame. The grinding wheel rack usually consists of the following parts: the main body of the rack, the spindle, the dynamic balance device of the grinding wheel, the horizontal feed mechanism, the convex (concave) forming mechanism, the power-off protection mechanism, etc.

If you are looking for rolls of rolling mills, please contact me.
Email: marketing2@hanrm.com.

More Articles You May Be Interested in: 

Failure Analysis of Cold Mill Roll

Material Selection of Rolling Mill Rolls

New Process Sendzimir Roll Features

An Effective Way to Reduce Mill Roll Consumption

What is Cold Roll?

Development of High-Speed Steel Rolls

How are the Rolls Classified by Material?

Design of Mill Rolls for Rolling Mill and Material of Rolls

The Cause of Rolling Mill Rolls Breakage

Sendzimir Mill Roll Maintenance

Roller FAQs

Disadvantages of the Heating furnace

Heating Defect of the Heating Furnace

1. Cracking of alloy steel.

At the beginning stage of heating (below 700 ℃), for high carbon tool steel, high manganese steel, bearing steel, high-speed steel and other steel with low thermal conductivity, if the heating rate is too fast, the surface temperature of the heating furnace rises suddenly and the temperature difference of cross-section is too large, thermal stress will be produced, leading to cracks.

2. Overheating and overburning.

If the heating temperature of the heating furnace is too high or the residence time at a high temperature is too long, the grain of the steel will grow excessively, the connection between grains will be weakened, and the steel will become brittle, which is called overheating. Even if there is no cracking in rolling, the mechanical properties of the finished product can not meet the requirements. It can be saved by normalizing the overheated billet. With the further development of overheating, the grains continue to grow up, and the grain boundaries are oxidized or melted, which is often broken or cracked during rolling, which is called overburning. The over burned blank is an irreparable waste. When the rolling operation breaks down suddenly, it is easy to cause overheating or overburning; if the temperature of high carbon steel is not controlled properly, it is also easy to cause overheating or overburning.

3. Oxidation and decarburization of billet.

During the process of billet heating in the heating furnace, metal elements in steel react with oxidizing atmosphere in the heating furnace and produce scale (the inner layer of scale is iron oxide, the middle layer is iron oxide, and the outermost layer is iron oxide). Decarburization is caused by the diffusion of carbon in steel to the surface and reaction with the atmosphere in the furnace. Decarburization of bearing steel, tool steel, spring steel and some other steels is harmful. The surface of decarburized steel can not reach the required hardness during quenching. In addition, the compressive performance, wear resistance and elasticity are reduced.

Oxidation and decarburization are carried out simultaneously, which are related to heating conditions (temperature, furnace time, furnace atmosphere and chemical composition of billet). Generally speaking, oxidation and decarbonization are not obvious when the temperature is less than 750 ℃. But when the temperature is higher than 800 ℃, it increases very fast.

In particular, the heating temperature of carbon steel should not be higher than 1300 ℃. Firstly, the oxide scale on the surface of steel billet will melt (the melting point of pure oxide scale is 1377 ~ 1565 ℃, and it will drop to 1300 ~ 1350 ℃ when it contains impurities), which will fall off the steel surface and expose a new surface, and the burning loss will increase rapidly. Secondly, when the heating temperature of the heating furnaces is higher than 1300 ℃, the billet is likely to overheat or overburnt. The maximum heating temperature should be paid more attention to when producing other kinds of steel.

After the billet is oxidized and burned, it will inevitably affect the yield; the thermal conductivity of the scale is very poor, which has an impact on the heating time of the billet; the scale falls off and accumulates in the heating furnace, which makes manual cleaning very difficult and hard work.

Inquiry about heating furnaces, please mail at marketing2@hanrm.com.

More Articles You May Be Interested In:

Alkaline EAF Oxidation Smelting Process

Roller Hearth Reheating Furnace

Classification of Electric Arc Furnace

Melting Features of Medium Frequency Electric Furnace

Electric Arc Furnace VS Intermediate Frequency Furnace

Why Intermediate Frequency Furnace cannot be Turned on Normally?

Energy-Saving Technology for Heat Treatment of Induction Furnace

Cause Analysis and Solution of Induction Coil Blocking in Medium Frequency Smelting Furnace

Characteristics of Electric Arc Furnace Steelmaking

What is Induction Furnace?

Significance of Reheating Technology in Rolling Reheating Furnace

How to Improve the Thermal Efficiency of the Reheating Furnaces?

What is the Reheating Furnace Temperature System?

The Advantage of Induction Furnace (Medium Frequency Furnace)

On the Advantage and Disadvantage of Electric Arc Furnace and Induction Furnace

Heating Furnace What You Need to Know

1. Heating furnace's purpose

The heating furnace is to heat the billet to a uniform temperature (austenite structure) suitable for rolling. After the temperature increases, the first thing is to improve the plasticity of the steel and reduce the deformation resistance, so that the steel is easy to deform. For example, the deformation resistance of T12 steel is about 600 MPa at room temperature, and it decreases to about 30 MPa when heated to 1200 ℃, which is only one twentieth of that at room temperature.

For the steel with proper heating temperature, a larger reduction can be used during rolling, which can reduce the equipment accidents caused by wear and impact, improve the productivity and operation rate of the rolling mill, and reduce the rolling energy consumption. Secondly, heating can improve the internal structure and properties of the billet. The inhomogeneous structure and non-metallic inclusions are homogenized by the diffusion of high-temperature heating. The heating temperature and uniformity are the marks of heating quality. The steel with good heating quality is easy to obtain the finished product with the correct section shape and accurate geometric size.

2. Heating furnace's heating process

The heating temperature of the billet includes surface temperature, temperature difference along with section and temperature difference along billet length. The final heating temperature of the billet in the furnace is determined after considering the actual situation of the rolling process, structural characteristics of the rolling mill and heating furnace. The time required for heating to the specified temperature depends on the billet size, steel grade, temperature system adopted and some other conditions.

The billet gets heat by convection and radiation in the heating furnaces. The former is that the furnace gas washes the billet surface, while the latter is that the furnace gas and hot lining radiate heat. Along the length direction, our furnace is divided into three sections: preheating section, heating section and soaking section. When the billet enters the preheating section of the heating furnace, the heat flux increases gradually. When the billet reaches the second heating section, the heat flux basically remains unchanged. When the billet reaches the soaking section, the heat flux decreases gradually.

In the soaking zone, the surface temperature of the billet remains basically unchanged, while the temperature difference of the cross-section decreases gradually, and the heat from the billet surface diffuses to the interior in the way of heat conduction. The smaller the heat flux to the billet surface, the larger the heating area, the smaller the section size of the billet and the greater the thermal conductivity of steel, the smaller the section temperature difference. Generally, the heating time of billets with large section is longer than that of billets with small section, and that of alloy steel is longer than that of carbon steel.

3. Heating furnace pressure system

The size and distribution of the heating furnace pressure are an important means to adjust the temperature field, control the flame and atmosphere in the furnace. It affects the heating speed and quality, and also affects the utilization of fuel. In particular, the furnace pressure at the discharge section of the furnace is particularly important.

The heating furnace pressure should be set at 0 ~ 30Pa higher than atmospheric pressure. If the furnace pressure is too high, the charging port, discharging port, observation hole and other opening parts will be exposed to fire. The results are as follows: (1) the furnace gas loss increases, which increases the heat loss; (2) SO 2 and other harmful gases enter the workshop, which pollutes the working environment; (3) the furnace wall, nearby steel structure or mechanical equipment at the burning part are damaged or deformed. On the contrary, if the furnace pressure is too low, the absorption of cold air in the workshop will make (1) the furnace temperature decrease and the fuel consumption increase; (2) the cooling of billet by low-temperature air will lead to uneven temperature; (3) the increase of oxygen content in the furnace gas will lead to the increase of burning loss.

4. Heating furnace combustion system:

The basic requirement is to ensure that the fuel is completely burned in the heating furnaces and the air coefficient α is small. Excess air leads to a large amount of flue gas and more heat carried away; insufficient air leads to incomplete combustion in the furnace, which also increases heat loss.

Inquiry about heating furnaces, please mail at marketing2@hanrm.com.

More Articles You May Be Interested In:

Alkaline EAF Oxidation Smelting Process

Roller Hearth Reheating Furnace

Classification of Electric Arc Furnace

Melting Features of Medium Frequency Electric Furnace

Electric Arc Furnace VS Intermediate Frequency Furnace

Why Intermediate Frequency Furnace cannot be Turned on Normally?

Energy-Saving Technology for Heat Treatment of Induction Furnace

Cause Analysis and Solution of Induction Coil Blocking in Medium Frequency Smelting Furnace

Characteristics of Electric Arc Furnace Steelmaking

What is Induction Furnace?

Significance of Reheating Technology in Rolling Reheating Furnace

How to Improve the Thermal Efficiency of the Reheating Furnaces?

What is the Reheating Furnace Temperature System?

The Advantage of Induction Furnace (Medium Frequency Furnace)

On the Advantage and Disadvantage of Electric Arc Furnace and Induction Furnace

What Is Continuous Casting Machine?

Continuous steel casting refers to the production process of continuously pouring high-temperature molten steel onto cast slabs with a certain cross-sectional shape and size specifications. To complete this process, the equipment required is called a complete set of continuous casting equipment. Mechatronics casting equipment, continuous casting fuselage equipment, cutting area equipment, and ingot bar receiving equipment, etc. constitute the continuous casting steel core equipment, which is often referred to as a continuous casting machine.

The continuous casting process of the continuous casting machine. When high-temperature molten steel is continuously poured into one or a group of cold copper molds, the molten steel gradually solidifies into a blank shell around the mold. When the steel liquid level rises to a certain height and the blank shell solidifies to a certain thickness, pull out the orthopedic machine and pull it out. The billet shell is cooled by spraying water in the secondary cooling zone to completely solidify the billet shell. Then, according to the needs of steel rolling, the cutting equipment cuts the billet into size. This process of pouring high-temperature molten steel directly onto the billet is called continuous casting.

Continuous casting machine can be divided into many different types. According to its structure and shape, the continuous casting machine can be divided into vertical curve, arc straight section, arc section, multi-radius ellipse, horizontal continuous casting machine and other types. With the development of continuous casting technology, wheeled continuous casting machine, especially thin slab continuous casting machines have been developed again.

If distinguished by the size and shape of its casting section, the continuous casting machine can be divided into slab continuous casting machine, billet continuous casting machine, bloom continuous casting machine, round billet continuous casting machine, special-shaped section continuous casting machine, and slab caster. The rectangular billet continuous casting machine also includes the rectangular billet on the rectangular billet continuous casting machine. The cast slab whose casting cross-section or equivalent sectional area is greater than 200×200mm is called bloom, and the cast slab with the cross-section or equivalent sectional area less than 160×160mm is called a small billet. Square billets, rectangular billets with a width ratio greater than 3 are called slabs.

According to how many slabs can be poured by the continuous casting machine in the same ladle, it can be divided into three types: single-strand, double-strand, and multi-strand.

 

The emergence of the continuous casting machine has fundamentally changed the one-time rolling and serving method of steel ingots for a century. The use of a continuous casting machine has the advantages of simplifying production procedures, improving production efficiency and metal yield, saving energy, greatly reducing production costs, and ensuring the quality of billets. It has developed rapidly at home and abroad. In today's steelmaking enterprises, it is almost inevitable to equip continuous casters, no matter if it is a long process or a short process.

If you are interested in purchasing the continuous casting machine, please mail at marketing2@hanrm.com.

More Articles You May Be Interested in:

1. Continuous Casting Machine

2. What is Continuous Casting and Continuous Rolling?

3. Continuous Rolling, Semi-continuous and Slit Rolling Processes of Rolling Mills

4. What is the difference between horizontal continuous casting and arc continuous casting?

5. Why Develop Horizontal Continuous Casting Technology?

6. What’s the Main Equipment of the Horizontal Continuous Casting Mill?

7. Continuous Casting Machine Equipment