The world No. 1 in crude steel production steel plant, over 70% of the HSS for bar and wire are from us.

SG rollS manufacturer

As a provider of high-durability SG rolls, LMM GROUP ensure our products are built to last. Our rolls undergo rigorous testing to guarantee they can withstand the toughest operating conditions, providing reliability and longevity.

SG rolls, or Spheroidal Graphite Iron rolls, are a type of rolling mill roll made from ductile iron. These rolls are known for their enhanced strength, toughness, and wear resistance compared to traditional cast iron rolls. The key to their performance lies in the microstructure of the iron, which contains spheroidal (nodular) graphite rather than the flake graphite found in grey cast iron. Here are the main features and applications of SG rolls:

Features of SG Rolls:

Material Composition:

SG rolls are made from ductile iron, which is a type of cast iron with nodular graphite inclusions.
The presence of spheroidal graphite provides improved mechanical properties.

Strength and Toughness:

The nodular graphite structure enhances the material’s strength and toughness, making SG rolls more resistant to cracking and impact damage compared to grey cast iron rolls.

Wear Resistance:

SG rolls have good wear resistance, making them suitable for applications where the rolls are subjected to abrasive wear.

Heat Resistance:

They exhibit good thermal conductivity and can withstand higher temperatures without losing their structural integrity.


Despite their strength, SG rolls retain good machinability, which is important for producing rolls with precise dimensions and surface finishes.

Applications of SG Rolls:

Metal Rolling Mills:

Widely used in hot and cold rolling mills for rolling a variety of metals, including steel, stainless steel, and non-ferrous metals.
Commonly used in roughing, intermediate, and finishing stands of rolling mills.


The enhanced mechanical properties ensure a longer service life, reducing the frequency of roll changes and maintenance costs.

Surface Finish:

SG rolls provide a good surface finish on the rolled products, contributing to the production of high-quality metal sheets, bars, and other forms.


Suitable for rolling various types of metals and alloys, making them versatile for different rolling mill applications.
Economic Efficiency:

The combination of durability and good performance characteristics often makes SG rolls a cost-effective choice for many rolling mill operations.

Comparison with Other Rolls:

Adamite Rolls:
SG rolls generally have better toughness due to the nodular graphite structure, while adamite rolls offer a balance of hardness and toughness.

Chilled Cast Iron Rolls:
SG rolls are tougher and more resistant to cracking, whereas chilled cast iron rolls have higher hardness but are more brittle.

backup rolls
steel mill rolls

Chemical Analysis

Designation of rollsMaterial code    CSiMnNi        CrMoMg
CrMo indefinite chilled SG cast iron rollsSG Ⅱ3.00-3.401.40-1.900.20-0.80 0.20-0.600.20-0.60≥0.04
NiCrMo indefinite chilled SG cast  iron rolls (Ⅰ)SG Ⅳ3.00-3.401.40-1.900.40-0.800.50-1.000.20-0.600.20-0.60≥0.04
NiCrMo indefinite chilled SG cast  iron rolls (Ⅱ)SG Ⅴ3.00-3.401.40-1.900.40-0.801.10-2.000.30-1.000.20-0.60≥0.04

Centritugal ocasting ( φ200-φ600) × 1050×3000: (φ500-φ1350)×1400~5300×11000
The monobloc casting is applied to all dimensions or roils. the maximum weight of rollisup to 80T.

Physical Properties

Designation of rollsMaterial codeBarel hardness (HSD)Neck hardness  (HSD)Tensile strength
CrMo indefinite chilled SG cast iron rollsSG Ⅱ50-7035-55>320
NiCrMo indefinite chilled SG cast iron rolls (Ⅰ)SG Ⅳ55-7035-55>320
NiCrMo indefinite chilled SG cast iron rolls (Ⅱ)SG Ⅴ60-7035-55>320



In the field of backup rollers, LMM’s goal is not only to become an important manufacturer of backup rollers, but also to lead the development of backup roller technology. As early as the 1980s, LMM Support Roller Manufacturing Factory successfully developed and produced support rollers weighing more than 100 tons; at the beginning of the 21st century, LMM Support Roller Manufacturing Factory successively developed Cr2, Cr3, Cr4, and Cr5 series backup roll materials meet the requirements of rolling technology for backup rolls and are still used today; in recent years, LMM backup roll manufacturing plant has developed Cr8 backup rolls with better wear resistance and stronger fatigue spalling resistance. In terms of research and development work, we have now mastered the material properties of Cr8 backup rollers and are in the stage of looking for manufacturers to conduct product trial production.

rolling mill rolls

Visit LMM Production workshop - Manufacturing strength

Main equipment: 60t electric arc furnace, 80t electric arc furnace, 40t, 150t ladle refining furnace.

Main equipment: 600t, 400t, 200t, 100t vacuum ingot casting chamber.

Main equipment: 160MN free forging hydraulic press, 125MN free forging hydraulic press, 80MN fast forging hydraulic press.

High-precision machining equipment

backup rolls

Ⅰ. Smelting and pouring process


Main equipment: 60t electric arc furnace, 80t electric arc furnace, 40t, 150t ladle refining furnace.


Main equipment: 600t, 400t, 200t, 100t vacuum ingot casting chamber.

Ⅱ. Forging process

Main equipment: 160MN free forging hydraulic press, 125MN free forging hydraulic press, 80MN fast forging hydraulic press.

backup rolls

Ⅲ. Heat treatment process

After the continuous rolling backup rolls are heated, they are discharged and quenched.

backup rolls

Back-up rollers of wide and heavy plate rolling mill are released and quenched

Ⅳ. Heat treatment process

HSS ROLLS manufacturer

Ⅴ. Package

backup rolls

Manufacturing quality system

LMM Back-up Roller Manufacturing Factory is one of the earliest enterprises in China to implement total quality management, GB/T10300, and ISO9000 standards. It has now formed a complete and effective quality management system.
The company has successively obtained GB/T19001-ISO9001 and GB/T19002-ISO9002 quality management system certifications.

Use and management of backup rolls for hot-rolled strips

Shape is an important quality index of strip steel, and roll wear is one of the key factors affecting the final shape of strip steel. The roll wear includes back-up roll wear and work roll wear. Since the roll changing cycle of the backup roll is much longer than that of the working roll, its serious wear will affect the bending deformation of the working roll, which will also affect the strip shape quality. Roll wear is one of the factors that are difficult to quantitatively control in current production.

Our Client Say?

The trial data shows that the ∮370mm high-speed steel roll produced by LMMGROUP has far exceeded the single-groove assessment value of 1,500 tons in the “Roll Ordering Technical Agreement”, and the effect is good.

On September 10, 2015, in the rolling process of the steel rolling mill, the LMMGROUP high-speed steel bar rolling experiment was carried out on the first bar line C12 to four cuts, and C14 three cuts to K1, K2, K3, and K4. According to the trial situation, The average amount of steel passing through LMMGROUP rolling is about 50%-60% of the alloy rolling spoke. The processing difficulty of high-speed steel is low, and the processing cost is lower than that of the alloy rolling wheel. Our factory can achieve normal processing.

Rolling Mill Roll Manufacturer​

Pre-Sales Service

* Inquiry and consulting support.

* Planning layout and Design requires machinery

* Welcome visit our Factory.

* The production process and before leaving the factory, all performance indicators are strictly tested, and the professional QC team controls according to the process.

After-Sales Service

* Engineers available to service machinery overseas.

* IN-TIME delivery goods.

* The quality is tracked throughout the process, and the installation and use are guided throughout the process.

* Long-term technical support.

* Stick to the agreement, do not do anything that violates the agreement, stick to the spirit of the contract to the end.

LMM GROUP have been supplied to world’s top steel manufacturer :

United Arab EmiratesEmirates Steel
Egypt:Ezz Steel
Russia:MMK,Mechel, NLMK

Luxembourg:RIVA Group,ArcelorMittal
Turkey: Tosyalı Holding,İçdaş,Erdemir Group
Spain: Liberty Steel Group,CELSA Steel Group
India: tata-steel,SAIL, SPL,Erdemir Group etc. We do OEM for Concast and Danieli for a long time

Contact US Now !

We would be happy to help and advise if you have any questions or inquiries.

Contact US Now !

We would be happy to help and advise if you have any questions or inquiries.