Rolling Mill Stand

Rolling Mill Stand

Rolling Mill Housing, also called Rolling Mill Stand, Mill Frame, Mill Housing Frame, or Rolling Mill Stand Housing, is one of the core load-bearing components in hot rolling mills, cold rolling mills, section mills, bar mills, wire rod mills, plate mills, and strip mills. It accommodates all core components of the rolling mill, including rolls, bearings, bearing chocks, and roll adjustment devices. Its main function is to support rolls, bearing chocks, screw-down systems, and transmission systems while absorbing enormous rolling forces generated during steel rolling operations.
Vertical rolling mill stands are usually made of high-quality cast steel or welded steel structure, which need to bear all the rolling force during the rolling process, and transmit the load to the foundation. Whether it is a hot rolling production line for steel, a cold rolling mill, or a non-ferrous metal rolling production line, high-performance rolling mill housing is the core guarantee for the stable operation of the entire production line.
BOPENG specializes in manufacturing large cast steel vertical rolling mill housings of various structures and tonnages with high strength, high rigidity, excellent fatigue resistance, and superior dimensional stability for steel, metallurgy, mining, and heavy industrial applications.

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Main Function of Rolling Mill Stands

As a critical heavy-duty cast steel component, the rolling mill housing directly determines the rolling precision, equipment rigidity, product dimensional accuracy, production stability, and service life of the rolling mill. Supporting Rolling Rolls: The rolling mill housing securely supports work rolls and support rolls via rolling mill bearing chocks. Absorbing Rolling Force: The mill stands can absorb enormous rolling pressure generated during hot or cold rolling operations. Maintaining Mill Alignment: The high rigidity characteristics ensure the stability of rolling accuracy and strip thickness. Reducing Vibration: A properly designed rolling mill housing can minimizes vibration, and improving the surface quality of the rolled material. Ensuring Operational Safety: The heavy-duty structural design ensures that the equipment can operate safely and continuously under extreme load working conditions.

Rolling Mill Housing Structure

A rolling mill housing is the massive structural frame that supports the rolling rolls and transmits rolling force to the mill foundation during metal deformation. It commonly consists of window frame, posts/columns, cross beam, screw-down device seat, bearing chock guide surfaces, and base support section.

BOPENG rolling mill stands can be divided into different structural types:

Open Type Rolling Mill Housing

Also called closed frame rolling mill stand, it is an integral closed frame structure with high overall rigidity, good stability, and can withstand large rolling force, suitable for heavy-duty roughing mills and finishing mills. This structure has small deformation during rolling, which can ensure high rolling accuracy, and is the most widely used structure in modern large-scale production lines.

Closed Split Type Housing

A kind of split-type rolling mill housing, composed of two side walls separated, upper and lower beams, connected into a whole by pre-stressed bolts. Split rolling mill housing, with a middle spacer structure. This structure is easy to disassemble, which is convenient for roll changing and equipment maintenance, and is suitable for modern rolling mills that require frequent roll changing.

Half Housing Pre-stressed Structure

A kind of high-precision pre-stressed rolling mill housing, through the pre-stressed design of the pull rod, can offset part of the deformation when rolling, improve the overall rigidity of the rolling mill, and can control the accuracy of the head and tail of the rolled piece within ±0.06mm, which is suitable for high-precision finishing rolling occasions.

In the traditional rolling mill production line, the split rolling mill housing usually adopts the structural form of two vertical side walls and horizontal beams. Each vertical frame consists of two side walls are arranged side by side at a certain distance, connected by horizontal beams, fixed by pre-stressed bolts, and equipped with walking wheels on the bottom, which can move along the track to facilitate roll changing and maintenance.

Materials of BOPENG Rolling Mill Stands

BOPENG selects high-quality raw materials according to different working conditions and load requirements, to ensure that the rolling mill housing has sufficient strength, toughness, and fatigue resistance.
For the manufacturing of rolling mill housings, we strictly control the content of impurities: Sulfur ≤ 0.015%, phosphorus ≤ 0.025%, far lower than the national standard limit, effectively avoiding the brittleness caused by impurities, and improving the toughness and fatigue resistance of the material.

Material Grade

Main Performance

Applicable Scenarios

ZG230-450 (ZG25)

Good casting performance, good welding performance, good plasticity and toughness, moderate strength, suitable for medium load structural parts

Medium and small rolling mill housings, general working conditions

ZG270-500 (ZG35)

High strength, good toughness and plasticity, good machinability

Medium and heavy rolling mill housings are the most commonly used material for general rolling mill housings

ZG310-570 (ZG45)

Higher strength, good wear resistance, suitable for heavy load working conditions

Heavy-duty rolling mill housings, roughing mill housings under large impact load

ZG35CrMo

High strength, excellent toughness, good hardenability, good impact fatigue resistance, yield strength ≥ 510MPa, tensile strength ≥ 700MPa

Extra-heavy rolling mill housings, large hot rolling mills, and high-load working conditions

ZG42CrMo

Ultra-high strength, excellent comprehensive mechanical properties, good low temperature impact toughness, can meet the demand of extra-heavy loads

Large heavy-duty rolling mill housings, roughing mill housings for large section steel, and strip mill housings

Mechanical Properties

Property

Typical Value

Tensile Strength

500–750 MPa

Yield Strength

280–450 MPa

Elongation

≥18%

Impact Toughness

≥35 J

Hardness

HB180–260

Advantages of BOPENG Cast Steel Rolling Mill Housing

As a professional cast steel parts manufacturer, BOPENG’s rolling mill stand has the following outstanding advantages:
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High Rigidity and High Precision, Improve Rolling Quality

– High-quality alloy cast steel material, optimized structure design through finite element analysis, the overall rigidity is high, and the elastic deformation during rolling is small.
– Pre-stressed rolling mill housing can effectively offset the rolling deformation, the overall stiffness coefficient is increased by more than 30%, effectively improving the dimensional accuracy of rolled products, and the head and tail accuracy deviation can be controlled within ±0.06mm, meeting the requirements of high precision rolling.
– Strictly control the processing accuracy, the parallelism and position tolerance of each matching surface meet high standards, ensuring the assembly accuracy, and ensuring the stable operation of the rolling mill.

High Strength and High Toughness, Long Service Life

– Strictly control the impurity content of the material, sulfur control ≤ 0.015%, phosphorus ≤ 0.025%, ensure that the material has high strength and good impact toughness.
– After reasonable heat treatment, the material structure is uniform, the fatigue resistance is good, can withstand long-term alternating impact load; the service life is 1.5-2 times that of ordinary products.
– 100% non-destructive testing, to ensure that there are no harmful internal defects, and to avoid the hidden danger of cracking during use.

Full Customization, Adapt to Various Working Conditions

– We can produce according to customer drawings, any size within 200 tons can be customized.
– Can be designed according to your rolling force, rolling process, and other working conditions, and recommend the most suitable material and structure.
– We can provide open type, closed split type, pre-stressed type, pre-stressed short stress line, and other structural types to meet the needs of different production lines.

Complete Production Capacity, On-time Delivery

– We have large-scale production equipment, from casting, heat treatment, processing, and testing, a complete production line, which can meet the production demand of a large extra-heavy rolling mill housing.
– Standard production management, control the production cycle reasonably, and ensure on-time delivery.
– Professional after-sales service, providing technical guidance for installation and commissioning.

Cost Advantage, Save Your Procurement Cost

– Optimized design through finite element analysis, under the premise of ensuring performance, reasonably reduces the weight of the product, reduce the procurement cost.
– One-stop production from smelting, casting, processing, and testing reduces intermediate links, competitive price.
– Long service life reduces the frequency of replacement and reduces the overall operating cost of the production line.

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BOPENG’s Solution for Cast Steel Products

BOPENG support fully customized large casting steel products in widely applications, including building material industry, metallurgical engineering, and mining industry. We supply one-stop solution from drawings to finished products.

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FAQ

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Steel casting and steel forging are two different manufacturing processes used to produce high-strength steel components, but they create different material structures and design advantages.
Steel forging forms metal through mechanical deformation under high pressure, which improves grain flow and is often selected for parts requiring extremely high fatigue resistance and directional strength. Steel casting, on the other hand, produces components by pouring molten steel into a precisely designed mold, allowing manufacturers to create complex geometries, large structures, and integrated components that would be difficult or impossible to manufacture through forging.
For many heavy industrial applications, steel casting provides significant advantages because it allows complex shapes, internal passages, thick sections, and customized designs while maintaining excellent strength, toughness, and wear resistance. This makes cast steel widely used for mining machinery, construction equipment, railway components, pump bodies, valve components, and power generation equipment.
The selection between casting and forging depends on factors such as component size, structural complexity, mechanical requirements, production volume, and operating environment. A professional steel casting manufacturer can help determine the most suitable process according to the actual application requirements.

Choosing the correct steel grade is one of the most important steps in designing a reliable steel casting component. The ideal material depends not only on strength requirements but also on the working environment, temperature, corrosion exposure, impact loads, and wear conditions.
Carbon steel castings are commonly selected for general industrial applications where good strength, machinability, and cost efficiency are required. Alloy steel castings are preferred for more demanding conditions because alloying elements such as chromium, nickel, molybdenum, and manganese can improve hardness, toughness, heat resistance, and wear performance.
For example, mining equipment components often require high impact resistance and abrasion resistance, while valve bodies and pump components used in energy or chemical industries may require corrosion resistance and high-temperature stability.
During material selection, engineers usually consider mechanical properties such as tensile strength, yield strength, elongation, hardness, impact toughness, and heat treatment requirements. A properly selected steel grade ensures that the casting performs reliably throughout its service life rather than simply meeting initial specifications.

Mining and heavy construction equipment operate under some of the most severe working conditions, including heavy impact, continuous vibration, abrasive materials, and extreme loading cycles. These environments require components with exceptional strength and durability.
Steel castings are widely used in these industries because they provide an excellent balance of mechanical strength, impact resistance, and design flexibility. Components such as crusher parts, excavator components, structural brackets, machine frames, and wear-resistant parts can be manufactured with complex shapes while maintaining high load-bearing capability.
Compared with other materials, steel castings can be engineered with specific alloy compositions and heat treatments to achieve improved hardness, toughness, and fatigue resistance. This makes them suitable for equipment that must operate continuously in mines, quarries, and heavy industrial environments.
The ability to produce large and complex components is another important advantage of steel casting, especially for heavy machinery where welded assemblies may introduce additional stress concentration points.

Steel casting quality depends heavily on controlling the entire manufacturing process, from melting and mold preparation to pouring, solidification, and heat treatment.
Common casting defects may include shrinkage cavities, gas porosity, inclusions, cracks, and dimensional variations. These issues usually result from factors such as improper molten steel treatment, incorrect pouring temperature, poor feeding design, uncontrolled cooling rates, or inadequate process parameters.
Professional foundries use multiple methods to reduce casting defects, including chemical composition control, simulation-assisted mold design, riser optimization, advanced melting technology, and strict inspection procedures.
Quality verification may include visual inspection, dimensional measurement, ultrasonic testing, magnetic particle testing, radiographic testing, and mechanical property testing. These inspection methods help ensure that steel castings meet customer specifications and perform safely in demanding industrial applications.

Heat treatment plays a critical role in improving the mechanical properties and long-term reliability of steel castings.
After casting, the internal structure of steel may contain residual stress and uneven microstructures caused by the cooling process. Heat treatment processes such as normalizing, annealing, quenching, and tempering help refine the grain structure, relieve internal stress, and achieve the required combination of strength, hardness, and toughness.
For heavy-duty applications, heat-treated alloy steel castings can provide significantly improved resistance against impact loads, fatigue failure, and mechanical deformation. For example, components used in mining machinery, railway equipment, and industrial processing systems often rely on carefully controlled heat treatment to achieve stable performance under continuous operation.
The correct heat treatment process depends on the steel grade, casting size, wall thickness, and final application requirements.

Custom steel castings are used across many industries where components require high strength, durability, and complex geometries.
Major application areas include mining equipment, construction machinery, oil and gas systems, power generation equipment, railway transportation, marine engineering, industrial pumps and valves, and heavy manufacturing machinery.
In the mining sector, steel castings are commonly used for wear-resistant and load-bearing components. In oil and gas applications, cast steel components are selected for their ability to withstand pressure, temperature variations, and harsh operating environments. Power generation and energy industries also rely on steel castings for critical equipment requiring high reliability.
Because steel casting allows manufacturers to create large, complex, and customized components, it remains an important manufacturing solution for industries requiring performance beyond standard fabricated parts.

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