Monday, May 13, 2024

Coke Oven Door And Frame

The coke oven doors of coke ovens are generally iron-on-iron self-sealing, that is, knife-edge doors. The tightness of the doors is closely related to preventing smoke and fire, as well as the deformation and failure of the furnace frame and furnace columns. Therefore, the furnace door, which is not usually a furnace protection device, is actually a very important furnace protection device.

Tuesday, February 27, 2024

Analysis of Factors Affecting the Life of Mold Copper Tubes


Analysis of Factors Affecting the Life of Mold Copper Tubes

This article describes the reasons that affect the life of the mold copper tube and the corresponding measures to be taken.

Key words: copper mould tube; service life of copper tube; countermeasures

Main reasons restricting the service life of copper tubes

Copper mould tube vibration table

The billet continuous casting machine adopts the semi-plate spring imitation positive rotation vibration system, but due to the occurrence of steel leakage accidents in actual production, the vibration frame exposed to the lower mouth of the copper mould tube is most likely to be adhered by molten steel or residual steel residues enter the vibration mechanical parts , affect the accuracy of the vibration parameters, and even produce polarization phenomenon, which will cause the leaf spring to break in severe cases, which will bring great hidden dangers to the quality of the billet and the normal use of the copper tube.

When the vibrating leaf spring has a long service life, the leaf spring produces linear plastic extension, and the arc of the copper tube in the copper mould tube does not coincide with the basic arc of the casting machine, resulting in excessive resistance during casting, resulting in transverse cracks, and the service life of the copper tube shorten.

Assembly of tension leveler

Billet continuous casting machine drawing and leveling machine system is mainly composed of a set of drawing and leveling upper and lower rolls, a set of free rolls, a set of stripping upper rolls and lower rolls and frame, base, transmission system, hydraulic cylinder, etc., for Five-roller two-point straightening structure, but due to the relatively weak maintenance force of our factory and limited technical level, it often happens that the dummy bar deviates from the lower mouth of the copper mould tube when feeding the dummy, which cannot ensure the accuracy of arc alignment and artificially increases the billet The resistance increases the wear of the chrome-plated layer of the copper tube.

copper mould tube assembly

The key parameter of mold assembly is the adjustment of the water gap. Whether the water gap is even on both sides directly affects the quality of the billet and the service life of the mould. Quality accidents such as deformation and corner cracks, and single-strand production accidents such as breakouts, severely restrict production and affect the quality of billets and the service life of mold copper tubes.

copper mould tube reverse taper

The size of the taper of the mold must be appropriate. Excessive taper will cause the mold to squeeze the billet shell, resulting in concave corners, increased friction between the billet shell and the copper tube of the mold, and aggravated the wear of the copper tube. For copper, hot spots can form in the corner area due to air gaps, causing shell thinning and cracking. If the taper is small, the air gap will increase, the heat flow will decrease, the billet shell will become thinner, and steel breakout will easily occur. In addition, if the taper is too small, the rotation of the corner will be aggravated, and subcutaneous cracks and longitudinal depressions will appear.

Corresponding measures taken

(1) Strengthen spot checks on the copper mould tube vibration device. Every time the copper mould tube is replaced or overhauled, a special person will check the gap between the leaf spring and the stand to prevent mold slag, cold steel, etc. from entering and causing copper mould tube polarization. In addition, after thecopper mould tube is replaced, the anchor bolts of the copper mould tube are fastened in place.

(2) The workshop and the factory strengthen the training of maintenance-related knowledge and operational ability to ensure that the basic data such as the longitudinal centerline and outer arc reference line of the continuous casting machine are identified during the continuous casting repair and overhaul.

(3)copper mould tube assembly.

a. For the off-line copper mould tube, do a good job of confirming the inner wall of the copper tube, dismantling it, checking the aging of the sealing rubber ring, whether there is any abnormal change in the water joint between the copper tube and the water jacket, and whether there are foreign objects in the copper mould tube, etc., and analyze the specific Make a record of the reason for the offline.

b. The inspection of new copper pipes and water jackets is strictly in accordance with the requirements of the drawings, and all spare parts of the copper mould tube are measured, and they can only be put on the line if they meet the requirements. To ensure the accuracy of spare parts when the copper mould tube is repaired.

c. During the process of dismantling and assembling copper pipes, two key points must be ensured: stability and accuracy. Prevent pits from appearing due to local stress on the copper pipe, and deformation of the water joint adjustment device, which will ultimately affect the assembly accuracy of the copper pipe. It is strictly forbidden to use sharp objects in the installation of the sealing rubber ring to prevent the damage of the rubber ring that is not easy to observe.

d. The adjustment of the water joint is the core content of the repair of the copper mould tube. The upper water joint of the copper pipe should be positioned with the matching copper pipe and water jacket before assembly. The deviation of the upper water joint is not allowed to exceed 0.5mm, and the lower water joint of the copper pipe The seam deviation does not exceed 0.2mm to ensure the water seam accuracy during assembly. Avoid billet defects caused by uneven cooling in copper pipes due to uneven water seams.

e. After the assembled copper mould tube is tested for water and pressure for 30 minutes, it can be put into use without leakage or loss of pressure, and records should be made.

Other measures to increase the steel passing capacity of copper pipes

(1) In the process of dismantling and inspecting the copper mould tube, foreign objects occasionally appear in the water chamber, and protective measures should be implemented in time according to the different foreign objects. Such as the water flushing method of the copper mould tube, the water quality management method of the copper mould tube, and the installation of pipeline filters, etc.

(2) During the maintenance process, focus on the arc calibration accuracy of the casting machine, adjust the guide edge spacing of the secondary cooling guide roller, and take measures such as water bar alignment, which effectively reduces the impact on the life of the copper tube due to eccentric wear.

(3) Adjust the production organization mode, reduce the number of stop flow, stabilize the casting speed, and effectively reduce the impact of start stop flow on the life of the copper tube.

Thursday, January 11, 2024

LMM GROUP Online Automatic Steel Bar Counting And Separation System


1) The counting accuracy of our rebar counting machine is as high as 0.02%.

2) The system could work 24 hours/day continuously, Increasing productivity.

3) The system could control the number/weight of every bundle, and decrease the production cost.

4) The system’s cost is very low, and the spare parts are also inexpensive.

5) It will achieve Full Automation, and enhance the plant’s image.

6) Fast Installation and easy operation: It only needs 15 days to install and commission and 5 days to teach your worker how to operate.

7) It could install on stop time, not influence the production.

8) The free warranty period of one year, life-long free update system.

LMM GROUP Online Automatic Steel Bar Counting And Separation System

Thursday, December 8, 2022

Steel Bar Counter System Machine Learning

 Background of the project:

In 2016, two sets of steel bar counting machine separation equipment were installed, and in 2019, the light source was upgraded and upgraded. Currently, there are 3 sets of red lights. The diameter of rebar produced is 8-50mm, and the operation and accuracy of the equipment have been normal, but there have been many counting errors in recent months.

For the current problems encountered, LMM GROUP immediately sent engineers to the local steel mills for on-site investigation.

Question one:

About 2-3 months ago, when producing medium-diameter rebar, there was a problem of low counting when the medium diameters were mainly 20, 25, 32, and 40mm, and generally 1-2 pieces were missing.
After the on-site video confirmation, there are currently possible reasons:
1) The end face of the threaded steel is uneven, and more dots
2) If the threaded steel is too close, superimposed, etc., do more
3) If there are iron filings and sundries on the surface of the threaded steel, do more
4) The threaded steel has too much deflection, more dots
The above reasons can be accurately counted after on-site adjustment.


Question two:
Because the current production pace is relatively fast, the cooling time is short, the ambient temperature is high, and other factors, resulting in blue blackheads on the end face of the rebar, mainly in the diameters of 14, 16, 18 and 20mm, and the counting deviation will increase, and there will be several more branch situation. And the customer adjusted the angle of the light source by himself, which is also one of the reasons.

  1. Readjust the position of the light source to ensure that the end face is in the brightest state
  2. Adjust the brightness of the light. At present, the brightness after the adjustment of the x-ray is 90, and the brightness after the adjustment of the v-line is about 55. Ensure that the critical value can meet the end face of ordinary and blue black heads, and inform the customer that it can be fine-tuned according to the actual production situation.
  3. Correct the camera 1:1 ratio
  4. It is recommended that customers upgrade to the latest pure blue light, which can better solve the problem of blue blackheads
  5. The customer currently does not have a chain speed difference, which causes the rebars to stick together. Today, the diameter of 14mm is produced. If the diameter is smaller, there will be piles of steel.
    At present, through the test of the first-stage chain speed of 220mm/s and the second-stage chain speed of 380mm/s, it is recommended that the customer adjust the first-stage chain speed to 200mm/s, and the second-stage chain speed to 450mm/s, and then observe the effect and adjust gradually.

Question three:
The customer’s v-line will produce a bundle of steel bars with a diameter of 8mm and 840 pieces according to customer requirements. The current limit for a bundle is 599. According to the parameters of adjusting the number of counts per bundle, it is adjusted to 1399 to meet customer requirements.


Monday, November 21, 2022

Introduction of chilled cast iron rolls


What kinds of commonly used cast iron rolls are there?

Cast iron rolls are further divided into four categories: chilled cast iron rolls, infinite chilled cast iron rolls, ductile iron rolls and high chromium cast iron rolls.
Due to the difference in composition, inoculation, cooling rate, heat treatment, etc., cast iron has formed a huge system. Various cast iron rolls have different structures and properties and can be used in different rolling mills.

Alloy chilled cast iron roll

Alloy chilled cast iron roll (roll ring) is a cast iron roll manufactured by using the subcooling degree of molten iron itself and the cooling of the mold surface, and adding Ni, Cr, Mo alloy elements at the same time. The basic structure of the working layer of the roll body is basically There is no free graphite, so it has high hardness and excellent wear resistance.
This kind of material can be used to produce large-scale rolls by static composite casting process, so that the roll body has high hardness and the roll neck has high strength and toughness, showing good thermal stability and accident resistance.

CC-1Chilled cast iron2.9-3.80.4-1.00.2-1.00.2-0.6 0.2-0.6
CC-2Chilled cast iron2.9-3.80.4-1.00.2-1.00.2-0.60.5-1.00.2-0.6
CC-3Chilled cast iron2.9-3.80.4-1.00.2-1.00.2-0.61.0-3.00.2-0.6
CC-4Chilled cast iron2.9-3.80.4-1.00.2-1.00.2-0.6 0.2-0.8(0.1-0.3)

Alloy Unbounded Chilled Cast Iron Rolls

Alloy unbounded chilled cast iron rolls. Graphite is uniformly dispersed throughout the cross section of the roll body, and its number and size increase with depth. The alloy unbounded chilled cast iron rolls provided by our company are due to the addition of manganese, chromium, nickel, molybdenum and other alloying elements, plus the presence of a small amount of fine graphite. It not only the peeling resistance, thermal crack resistance and wear resistance of the roll are improved, but also the working layer of the roll body has a smaller hardness drop and the fine graphite pores on the surface also improve the bite ability of the roll.

High nickel-chromium unbounded chilled cast iron rolled spokes

High-nickel-chromium unbounded chilled composite cast iron rolls are high-performance rolls manufactured by centrifugal or full flushing methods. By increasing the content of nickel, chromium, molybdenum and other alloying elements, high microhardness of microstructure and carbide can be obtained; with special heat treatment, a working layer with uniform structure, compactness and small hardness drop can be obtained; at the same time, it contains a small amount of free graphite, so it has good microhardness. Abrasion resistance, thermal cracking resistance, spalling resistance and indentation resistance.

Professional manufacturer of chilled cast iron rolls

Founded in 2007, LMM GROUP mainly produces all kinds of metallurgical rolls for various types of steel, bar, high-speed wire and strip hot and cold plate and strip rolling mills.

The company covers an area of 100,000 square meters, including two complete production lines for cast rolls and forged steel rolls, processing workshops, product research and development centers, testing centers, training centers and office buildings and other supporting facilities. The factory environment is very beautiful.

LMM have been supplied to world’s top steel manufacturer Arcelormittal, TATA Steel, EZZ steel etc. We do OEM for Concast and Danieli for a long time

Sunday, November 20, 2022

what is forged rolls?


Forged Steel Work Rolls

Forged steel cold-rolled work rolls are important components of strip cold-rolling mills, and their properties directly affect the shape, surface quality and rolling production efficiency of cold-rolled sheets.

Application: Widely used in various domestic and foreign single-stand and continuous rolling mill units, rolling different products such as automobile sheet, silicon steel, stainless steel, aluminum foil and so on.

Application: Applied to high-precision 6-high and 8-high mills, its performance directly affects the shape of cold-rolled sheets




Hardened layer depth

Hardness uniformity

Backup roller


70-88 HSD



Forged Steel backup roller

LMMGROUP support roller maximum diameter 1650mm

Application: Suitable for all kinds of four-high, six-high single-stand or multi-stand continuous rolling mills




Hardened layer depth

Hardness uniformity

Intermediate Roll





Forged steel roll technical Process:

Electric arc furnace smelting → LF \ VD refining → ingot casting → annealing → cleaning → electroslag remelting → annealing → forging → post forging heat treatment → rough machining → preliminary heat treatment → semi finishing → dual frequency quenching or differential temperature treatment → cryogenic treatment → tempering → finishing → packaging and delivery.