Comprehensive Guide to Universal Rolling Mills: Структура, Преимущества, Разработка & Технические параметры

Прежде всего, universal rolling mills act as core equipment for section steel production. A standard main mill stand includes one pair of horizontal rolls and one pair of vertical rolls. Кроме того, the axes of four rolls lie on the same flat plane.

To clarify function division, horizontal rolls serve as driving rollers. Vertical rolls usually work as driven rollers, while some upgraded models equip vertical rolls with independent driving systems. Above all, four rolls can compress workpieces from four directions at the same time. Тем временем, a two-high horizontal mill matches the universal main stand as an auxiliary edger mill.

Core Production Range of Universal Rolling Mills

For one thing, universal rolling mills earn their name from multi-product processing capacity. They can roll nearly all mainstream section steel types. Common finished products cover H-beams, steel rails, двутавровые балки, канал сталь, steel sheet piles, U-section steel, equal angle steel and unequal angle steel. For another thing, they support flexible batch production of different steel specifications.

Working Principle Matching Auxiliary Edger Mill

В общем, a complete universal rolling line combines one universal main mill and one two-high horizontal edger mill. Both stands adopt reversible rolling design to realize continuous rolling during production. Кроме, vertical rolls can be driven or passive, yet operators must keep identical linear speed between horizontal and vertical roll surfaces. Более того, manufacturers usually place the edger mill before or after the universal main stand to shape steel edges precisely.

Three Unique Advantages of Universal Rolling Mills

Compared with traditional two-high or three-high section mills, universal rolling equipment brings obvious economic and technical strengths.

Uniform deformation and low internal stress

Four rolls form complex integrated pass profiles. Thus all parts of steel cross sections receive simultaneous compression. На этом основании, speed differences across workpiece cross sections shrink sharply. In turn, finished steel carries tiny residual internal stress and avoids cracking defects.
Small rolls produce large-size section steel

Universal mills use small-diameter rolls to roll large-sized steel. Например, they manufacture wide-flange I-beams and high-web H-beams. Что еще более важно, they process H-beams with zero inner slope on flange sides, which traditional mills cannot realize.
Independent adjustment boosts output and cuts consumption

Operators adjust web reduction and flange reduction separately. This design simplifies daily mill calibration. According to real production data, universal rolling lifts total output by 1.8 раз, raises equipment operation rate by 10%, and cuts roll consumption by 20%.

Global Development History of Universal Rolling Mills

Early Foreign Innovation Stage (1902–1970)

The world’s first complete universal rolling line launched in 1902 at Arbed Steel Plant in Luxembourg. Nevertheless, wide-flange I-beams from this early unit still had inner flange slopes.

В 1908, Bethlehem Steel in the United States built the first special wide-flange H-beam factory based on Green rolling method. This standard required matched universal mill plus edger mill sets. Soon in 1914, Peine AG of Germany copied this technology and opened its H-beam production base.

Later in 1955, the European Coal and Steel Community developed standard IPE beam series. В 1957, Peine Steel produced the first batch of IPE beams. Even by 1970, I-beams still occupied the major share of global section steel output.

Global Popularization Boom After the 1960s

After the 1960s, worldwide steel industry expansion pushed fast universal mill upgrading. Most steel manufacturers reconstructed old heavy rail-beam mills with new universal equipment. Japan widely adopted this renovation route.

Between 1961 и 1972, Japanese steel enterprises renovated three large section plants and one rail-beam plant via imported universal mills. As early as 1965, Japan achieved mass H-beam production. By the late 1960s, the world owned 74 heavy section mills, 24 rail-beam mills and 12 wide-flange beam dedicated rolling lines.

Local Development History of Universal Rolling Mills in China

Limited by early technical and policy constraints, China lacked mature universal rolling technology for a long time. Domestic factories could not produce high-quality hot rolled H-beams independently.

In July 1998, Maanshan Iron & Steel put imported universal mills into operation and rolled China’s first qualified H-beam. This milestone opened a new chapter of domestic H-beam manufacturing. После, Laiwu Steel, Rizhao Steel, Jinxi Iron and Steel and other section steel manufacturers successively introduced overseas universal mill production lines. К 2007, domestic universal mill quantity grew rapidly, and most equipment relied on expensive foreign imports.

A key turning point arrived in 2003. А 300 H-beam production line designed and manufactured by Tianjin Zhongzhong Heavy Technology went online. This event marked China’s first domestically developed universal rolling mill formal commissioning.

Subsequently, self-developed universal mills for Dalian Zhengda, Tangshan Shengda, Anshan Zizhu and Anshan Baode steel plants started operation one after another. Как результат, China realized full localization of universal rolling equipment covering 100H to 600H full series H-beam specifications.

1. Product Mix & Production Scope

1.1 Rollable Steel Grades

Material types: Common carbon steel, low alloy structural steel, высококачественная углеродистая конструкционная сталь
Типичные оценки: Q195, Q235 and other standard structural steel

1.2 Complete Product Specifications

Narrow flange H-beam: 100×50, 125×60, 150×75, 175×90, 200×100
Medium flange H-beam: 150×100
Wide flange H-beam: 100×100, 125×125
I-Beam: 8# ~ 22#
Channel steel: 5# ~ 20#
Угловая сталь: 5# ~ 12.5#

2. Full Universal Rolling Mill Train Assembly Composition

A complete universal mill train contains multiple core modules:

Universal main mill, spindle support carriage, mill universal spindle, combined gearbox, main motor coupling, main drive motor.

3. Short Stress Line Universal Rolling Mill Core Technical Data & Структура

Core Function

It rolls intermediate steel blanks into qualified finished section steel according to specified hot rolling technological rules.

Тип мельницы

Short stress line universal rolling mill

Rated Rolling Force

Horizontal roll maximum rolling force: 3000 кН
Vertical roll maximum rolling force: 1500 кН

Roll Ring Sizes

Horizontal roll ring: φ830/φ720 × 220 мм
Vertical roll ring: φ540/φ470 × 185 мм

Roll Center Distance Adjustable Range

Horizontal roll: 850–720 mm
Vertical roll: 790–565 mm

Horizontal Roll Axial Adjustment Range

±4 mm (adjustable for both top and bottom horizontal rolls)

Horizontal Roll Neck Diameter

φ280 mm

Overall Mill Structure Breakdown

The universal mill consists of horizontal roll assemblies, vertical roll assemblies, support frames, roll gap adjusting devices, roll changing trolleys, guide beam and mill base.

Прежде всего, roll assemblies and gap adjustment devices form the mill core cartridge. Следующий, technicians connect the core cartridge with on-board piping via locking bolts to form a complete mill body. В конце концов, the whole mill body fixes onto the base through hydraulic locking bolt cylinders.

3.1 Горизонтальный & Vertical Roll Assembly Details

Horizontal Roll Assembly Structure

The horizontal roll set includes horizontal rolls, roll bearing + chock assembly, tie rod groups and support frames. Top and bottom rolls install on bearing chocks with rolling bearings at drive side and operation side. Each chock embeds screwdown nuts. Four tie rods pass through four intermediate support seats to link upper and lower chocks together. This layout forms the short stress line roll system.

Since the design cancels heavy mill housings, stress transmission paths only pass tie rods and built-in screwdown nuts. Therefore stress line length shortens significantly and mill springback reduces effectively. Более того, tie rod connected chocks optimize bearing stress state, lift bearing load capacity and extend service life.

Bearing Matching Scheme

Radial load: Four-row cylindrical roller bearings with high rigidity
Axial load: Double-direction thrust tapered roller bearings

Кроме того, spherical pads balance uneven force distribution on each rolling element row to prolong bearing service life. To cut load on screwdown devices and reduce tie rod abrasion, tie rod supports adopt rolling bearing structures. Labyrinth and skeleton oil seals stop cooling water and dirt entering bearing chambers.

Roll Balance & Axial Adjustment

Built-in elastic disc spring dampers inside tie rods eliminate thread clearance between tie rods and nuts. This design avoids radial roll runout caused by thread gaps. Тем временем, axial adjustment devices install inside operation side chocks of top and bottom rolls. Manual worm drive helical gears rotate threaded sleeves to push thrust bearings, inner sleeves and rolls for precise axial positioning. Counter-thread sleeves remove thread clearance and prevent loosening to realize accurate pass alignment.

Vertical Roll Bearing & Balance Design

Vertical rolls adopt double-row tapered roller bearings to bear both radial and axial loads. VD water seals plus skeleton seals block water and impurities. Сходным образом, tie rod built-in disc springs eliminate screw thread clearance to prevent vertical roll radial runout.

3.2 Independent Horizontal & Vertical Roll Gap Adjustment Devices

Horizontal Roll Gap Adjustment Unit

Main components: Hydraulic motor, transmission shaft, clutch, drive & operation side worm gear boxes. Worm gear boxes use welded box bodies with top calibrated dial scales.

One worm and worm gear pair equips each side box. Hydraulic motors drive worms to rotate worm gears. Gears below worm gears mesh with internal spline gear sleeves to turn tie rods and adjust horizontal roll gaps. Operators read screwdown positions via dial scales on tie rod tops. A hydraulic clutch on the operation side supports single-side independent adjustment to keep horizontal roll level.

Vertical Roll Gap Adjustment Unit

Main components: Hydraulic motor, worm gear set, screwdown nut and screw. Hydraulic motors drive worms to rotate worm gears. Internal threads on worm gears match screwdown screws to push screws forward or backward and change vertical roll gaps. Operation side and drive side vertical rolls support separate adjustment. Besides hydraulic drive, a manual adjustment backup device installs for emergency use. Operators check vertical roll positions through dial scales.

3.3 Welded Mill Base & Mill Horizontal Moving System

The mill base is an integral welded steel structure fixed on concrete foundations via anchor bolts. It carries two key hydraulic units: mill locking cylinders and mill traversing cylinders.

Mill locking cylinder: Disc spring locking + hydraulic release mode, fastens mill body onto base firmly during production. The mill cannot move unless locking cylinders fully release.
Mill traversing cylinder: Hydraulic drive realizes mill horizontal shift. Since this line adopts multi-pass rolling with fixed rolling centerline, mills must move horizontally to switch different roll passes.

Dual Function of Traversing Mechanism: Pass Switch & Full Cartridge Roll Change

The spindle support carriage connects with mill bodies via pin hydraulic cylinders and links traversing cylinders through inserting plates. Traversing hydraulic cylinders push whole mill bodies horizontally. When mills reach target positions, locking cylinders reset to lock the unit again.

For full cartridge roll replacement: Locking cylinders release first. Traversing cylinders push spindle carriage and mill bodies toward operation side to roll change station. Pin cylinders retract pins, then traversing cylinders pull spindle carriages back to drive side to separate roll spindle heads and universal spindles. After separation, roll changing trolleys replace old and new mill cartridges rapidly.

4. Spindle Support Carriage

Core Purpose

Balance total weight of universal spindles, clamp upper & lower spindles during roll change, and maintain horizontal spindle sleeve posture all the time.

Structure Type

Gantry frame style with mutual weight balance between upper and lower spindles plus spring buffer structure. Operators adjust central distance of upper/lower carriage symmetrically against rolling lines to match variable roll center distances.

Carriages install on mill bases. Chains and fixed pulleys link upper and lower bearing chocks together. Rolling bearing supports hold universal spindles inside liftable guide seats to provide continuous support. Mutual weight balance eliminates extra load on roll drive side bearings and stabilizes roll balance device stress. Hydraulic pin cylinders complete automatic connection and separation between carriages and mill bodies. Carriage bearings apply grease lubrication.

5. Mill Universal Spindles

Модель: Telescopic cross-shaft universal spindle

Количество: Two spindles per mill train

Interchangeability: Spindles of same specification can replace each other freely

Telescopic stroke: ±350 mm

6. Combined Gearbox

The combined gearbox integrates reduction gears and gear seat into one single unit. Two output shafts connect mill universal spindles to drive upper and lower horizontal rolls separately.

7. Main Drive Motor Coupling

Тип: Drum gear coupling with full safety protective housing.

8. Lubrication System Standard

Роликовые подшипники: Centralized grease lubrication
Mill liners and screwdown nuts: Manual grease filling

9. On-Board Medium Piping

All hydraulic, lubrication and cooling water pipelines arrange on mill bodies. Double flanges or quick connectors apply on all pipeline joint points for easy disassembly and maintenance.

10. Key Component Material Grades & Heat Treatment Rules

Tie rod, universal roll shaft, spindle sleeve, side screw rod: 42ХромМо
Horizontal roll chock: ZG270-500
Vertical roll chock: ZG35CrMo
Screwdown nut, side adjusting nut, roll trolley sliding plate: ZQAl9-4

All load-bearing core parts must receive specified heat treatment to meet mechanical performance standards.

Введение: Basic Definition & Core Composition of Universal Rolling Mills