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.

Thursday, April 15, 2021

Dephosphorization in the steelmaking process

The effect of phosphorus on the properties of steel

Phosphorus exists in the form of iron phosphide in steel, generally represented by [P]. Its specific effects on steel properties are:

Thursday, April 8, 2021

Defects of Special-shaped Billet Continuous Casting and Prospect of Solutions

 Abstract: This article presents an in-depth review of the literature on the defects of special-shaped billets, mainly focusing on the formation mechanism of defects, proposes solutions to reduce defects, shows the techniques used to investigate defects, and measures to improve the quality of molten steel and mold design in the continuous casting process , Secondary cooling modification and instrument calibration, sector support, continuous casting arc calibration, etc.