The Solution For Slower Start-Up Speed Of Rolling Mill Machine

The Solution For Slower Start-Up Speed Of Rolling Mill Machine

The speed at which the rolling mill machine is started during operation has an important effect on the efficient operation of the rolling mill. If the rolling mill machine is slow to start when it is ready for operation, it indicates that the rolling mill has obvious defects in performance, which will seriously affect the working efficiency of the rolling mill. The force between the blank or the rolled stock and the roll also does not reach a good condition.

The rolling stock cannot be fully rolled in the rolling mill. In this case, the power consumption of the rolling mill is several times higher than usual. If this happens frequently, the speed of the rolling mill is not effective when it is turned on. Increasing the efficiency of the billet or the rolled piece will lower and lower. For the rolling mill machine, if the rolling mill is not capable of rapid overload start, the billet rolling speed will be too slow, and Hani Tech will analyze it. The reason why the rolling mill machine startup speed is slow. 

Before starting the rolling mill machine, first check the motor power, rolling speed, product specifications, hole type process, etc., to ensure that the blank load capacity does not exceed the bearing capacity of the rolling equipment, otherwise the equipment start speed will be slower. There is also a need to check the bearing of the rolling mill to see if the lubrication of the bearing is sufficient. If the lubrication is not enough, the start of the rolling mill machine will be slower or even malfunction.

The Structure Of Flying Shear

The Structure Of Flying Shear

With rolling continuous, high-speed, highly developed degree of automation, flying shear has become a continuous rolling lone indispensable equipment, mainly for hot-rolled and cold-rolled unit length, cutting head, cut tail, cut the sample as well as incident handling, including cold-rolled strip steel drum flying shear, generally arranged before the winding machine, cutting the strip, for sub-volume …. 

As key equipment Rolling Integral continuous production line, support roller bear products at the online clipboard with curly taken to task. Acid rolling mill output of up to 500,000 yuan / h, whether the normal operation of the shears, directly determine whether the normal capacity of the entire line of play. 

A steel rolling mill in 420 acid production early l 998 in the first half, frequently appeared on the shears can not cut the strip normal phenomenon, causing huge economic losses.

With a flying shear structure, the drum-type mill bearing, generally composed of three parts flying shear body gear and equipment lubrication piping, whose chassis and rotating hub into one, as a whole, not only set up to replace the pair often transfer hub, simple structure rigidity, high cutting precision. 

Flying shear machine body is shown in Figure l, including the transmission mechanism, and cutting mechanism. Flying shear drive mechanism, mainly by the electric motor, gearbox, and synchronous transmission gear mounted on the upper and lower rollers on the drive side of the composition.

The Structure Of Rolling Mill

The Structure Of Rolling Mill 

A rolling mill has a common construction independent of the specific type of rolling being performed:

· Work rolls

· Backup rolls - are intended to provide rigid support required by the working rolls to prevent bending under the rolling load

· Rolling balance system - to ensure that the upper work and backup rolls are maintained in proper position relative to lower rolls

· Roll changing devices - use of an overhead crane and a unit designed to attach to the neck of the roll to be removed from or inserted into the mill.

· Mill protection devices - to ensure that forces applied to the backup roll chocks are not of such a magnitude to fracture the roll necks or damage the mill housing

· Roll cooling and lubrication systems

· Pinions - gears to divide power between the two spindles, rotating them at the same speed but in different directions

· Gearing - to establish desired rolling speed     

· Drive motors - rolling narrow foil product to thousands of horsepower

· Electrical controls - constant and variable voltages applied to the motors

· Coilers and uncoilers - to unroll and roll up coils of metal

Slabs are the feed material for hot strip mills or plate mills and blooms are rolled to billets in a billet mill or large sections in a structural mill. The output from a strip mill is coiled and, subsequently, used as the feed for a cold rolling mill or used directly by fabricators. Billets, for re-rolling, are subsequently rolled in either a merchant, bar, or rod mill. Merchant or bar mills produce a variety of shaped products such as angles, channels, beams, rounds (long or coiled), and hexagons.

The Usage And Features Of Ladle Refining Furnace

The Usage And Features Of Ladle Refining Furnace

LF refining furnace was successfully developed in 1971 by Japanese technical staff. And the furnace hasn’t had vacuum equipment, so the heating arc processing occurs on the steel surface of the slag in which LF refining furnaces the so-called submerged arc refining.

When adding the synthetic slag, stirring the molten steel with argon is necessary, and the refining occurs under a non-vacuum-reducing atmosphere. Afterward, the LF Furnace was improved, it can refining in the vacuum and heated under the non-vacuum circumstance when the vacuum extraction equipment is installed.

The main use of an LF refining furnace is for primary melting furnace (electric arc furnace, Converter, intermediate frequency furnace) refining of molten steel. It’s crucial metallurgical equipment for producing high-quality carbon steel, alloy structural steel, bearing steel, tool steel, stainless steel, etc, and meets the needs of Continuous Casting and Continuous Ligation.

This kind of LF refining Furnace has functions electric are heating, argon stirring, wire feeding, measuring temperature and sampling, alloying, etc. And in the terms of purchasing the LF refining furnace, the users can make choice by the steel grade and smelting technology.

The Usage And Types Of Straightener

The Usage And Types Of Straightener

The Usage of the Straightener

During the heating, rolling, finishing, and transportation process of the rolling piece, the external force, temperature changes, internal force changes, or some other factors, very easily lead to curve, deform, and some other variations, for solving these problems, we need to use a straightener to eliminate the stress from both inside or outside, then we can get straight final steel, the straightener is essential equipment in a rolling mill workshop, and is widely used for other workshops like cars and ships.

The Types of the Straightener

According to the requirement of the final product specification requirement, the straightener style would be the difference, divided by working theory, and application purpose can be divided as the following:

Press straightener

Parallel straightener

Cross rolls straightener

Stretch straightener

Bending straightener

Reverse straightener

Except for the above straightener, there are still a lot of special straighteners, basically, with the development of technology, the straightener will be promoted very quickly, for different requirements of the application.

The Usage Of Water In Rolling Mill Machines

The Usage Of Water In Rolling Mill Machines

With the development of the steel industry, more attention is paid to the protection of mechanical machines, such as roughing machines, reversible rolling mills, pre-finishing rolling mills, finishing rolling mills, and wire-rod mills. Therefore, most of the water used in the iron and steel industry is used for cooling, protecting equipment, and improving the working conditions of the employees. The Health and safety of the employee require dust control, which is commonly accomplished by sprinkling water on floors and machines.

Water use in all types of hot rolling mills is mainly for scale removal and temperature control. When steel is heated to the high temperature desired for hot rolling, its surface is oxidized and a hard scale is formed. If not removed before rolling, this scale would be rolled into the steel and would cause surface defects.  A common method of scale removal is to spray water under a pressure of as much as 2,000 psi (pounds per square inch) against the steel immediately before it enters the rolls.

Cooling water is sprayed on the rolls during hot rolling to prevent distortion and reduce erosion of the roll surfaces. Because considerable heat is produced by the rolling processes, water also serves to keep the steel at its proper rolling processes. Upon emergence from rolling mills, steel may be sprayed with water to hasten cooling. This spray prevents excessive scale formation. Roll bearings also require cooling. Spent cooling water flows to the scale pit along with that used for scale removal and may be reused after clarification and cooling.

The Use And Maintenance Of Roller

The Use And Maintenance Of Roller

The roller is the biggest wearing part, expensive so for reducing the cost, we should carefully maintain it.

1. Full quality test before entering the workshop

The roller is a high technology, high value-added product, should apply quality tests according to the quality standard, test the roller surface, and end’s hardness, the hardness deviation should be below ±（2-3）HS, apply ultrasonic to test the inside flaws, surface wave for testing surface quality, visual inspection for outside flaws.

2. Regular refacing

We should change the roller regularly for better protection even if the surface is flawless, roller working hours should be 50-100H, and the supportive roller should reface after 2000-3000h, for removing the working layer, the remover layer should be thicker than the working layer.

3. Use the roller in the right way.

Use the roller according to the guidance, should adjust the temperature to 70-80℃ when switching rollers, the cold roller should be at 30-50℃, should cold down in the water, and the roller neck should be lubricated, keep clean, avoid rusting and grinding damage iron sheet, prevent misoperation and accident.

4. Avoid roller break accident

Breaking down of  roller is a destructive accident, there are normally two reasons, one is because of the quality of the roller, normally we can find flows in the breaking point, the other reason is from the outside and causes the roller's power and torque is overweight, we should avoid this circumstance.