1780mm Steckel Hot Rolling Mill
1. Equipment Overview
This equipment is a 1780mm Steckel Hot Rolling Mill, primarily designed for hot rolling stainless steel, carbon structural steel and low-alloy steel. The production line adopts the Steckel rolling process, combining reversing roughing, reversing Steckel rolling and multi-stand finishing to complete the production process from slab reheating to finished hot-rolled coils.
The mill adopts a 1+1+3 configuration, consisting of one 4-Hi reversing roughing mill (R1), one 4-Hi reversing Steckel mill (S1) and three 4-Hi finishing stands (F1–F3), together with one edger (E1).
Two coiler furnaces are installed at the entry and exit sides of the Steckel mill, allowing strip reversing, coiling and temperature maintenance during the rolling process.
The annual designed production capacity is 1.2 million tons, with an overall yield of approximately 97%.
The equipment is suitable for 200-series, 300-series and 400-series stainless steels, as well as Q235 carbon structural steel and Q345 low-alloy steel. Additional grades include 304L, 316L and 2205.
For finished products, the carbon steel thickness range is 2.0–16.0mm, with a width range of 900–1,600mm. The stainless steel thickness range is 2.0–12.0mm, with a width range of 900–1,550mm.
The maximum coil weight is 26.8 tons for mild steel and 26.0 tons for stainless steel, meeting the production requirements of various hot-rolled strip specifications.
2. Main Technical Specifications
| Item | Technical Specifications |
|---|---|
| Equipment Name | 1780mm Steckel Hot Rolling Mill |
| Mill Type | Steckel Hot Rolling Mill |
| Mill Configuration | 1+1+3 |
| Annual Capacity | 1.2 million tons/year |
| Overall Yield | 97% |
| Steel Grades | 200-series, 300-series, 400-series stainless steel; carbon structural steel; low-alloy steel |
| Main Steel Grades | 201, 304, 316, 410S, 430, Q235, Q345 |
| Additional Steel Grades | 304L, 316L, 2205 |
| Finished Mild Steel Thickness | 2.0–16.0 mm |
| Finished Mild Steel Width | 900–1,600 mm |
| Finished Stainless Steel Thickness | 2.0–12.0 mm |
| Finished Stainless Steel Width | 900–1,550 mm |
| Coil Inner Diameter | Φ762 mm |
| Max. Coil Outer Diameter | Φ1,900 mm |
| Max. Coil Weight (Mild Steel) | 26.8 t |
| Max. Coil Weight (Stainless Steel) | 26.0 t |
3. Mill Configuration
The production line adopts a 1+1+3 mill configuration, mainly consisting of an edger, reversing roughing mill, reversing Steckel mill and three finishing stands.
Mill Configuration:
| Stand No. | Equipment | Mill Type | Quantity |
|---|---|---|---|
| E1 | Edger | Vertical Edger | 1 |
| R1 | Roughing Mill | 4-Hi Reversing Mill | 1 |
| S1 | Steckel Mill | 4-Hi Reversing Mill | 1 |
| F1 | First Finishing Stand | 4-Hi Finishing Mill | 1 |
| F2 | Second Finishing Stand | 4-Hi Finishing Mill | 1 |
| F3 | Third Finishing Stand | 4-Hi Finishing Mill | 1 |
The E1 edger is installed in the R1 roughing mill area and is primarily used for slab width adjustment. The R1 roughing mill performs initial rolling and thickness reduction, while the S1 Steckel mill further reduces the transfer bar thickness through reversing rolling.
The three finishing stands, F1–F3, perform the final rolling and thickness control of the strip.
The Steckel mill is equipped with entry and exit coiler furnaces to support strip coiling and temperature maintenance during reversing rolling operations.
4. Raw Material and Finished Product Specifications
(1) Slab Specifications
The equipment supports slabs with different thickness and width specifications.
| Item | Technical Specifications |
|---|---|
| Slab Thickness | 180 / 200 / 230 mm |
| Slab Width | 900–1,600 mm |
| Slab Length | 8,000–11,000 mm |
| Short Slab Length | 5,500 mm |
| Max. Slab Weight | 27.6 t |
| Standard Slab Size | 200 × 11,000 mm |
(2) Transfer Bar Specifications
| Item | Technical Specifications |
|---|---|
| Transfer Bar Thickness | 24–40 mm |
| Transfer Bar Width | 900–1,600 mm |
| Entry Temperature at Steckel Mill | ≥950°C |
After rough rolling and related processing, the transfer bar enters the Steckel mill for further thickness reduction. The required entry temperature at the Steckel mill is at least 950°C.
(3) Finished Product Specifications
| Product Category | Finished Thickness | Finished Width |
|---|---|---|
| Mild Steel | 2.0–16.0 mm | 900–1,600 mm |
| Stainless Steel | 2.0–12.0 mm | 900–1,550 mm |
(4) Coil Specifications
| Item | Technical Specifications |
|---|---|
| Coil Inner Diameter | Φ762 mm |
| Max. Coil Outer Diameter | Φ1,900 mm |
| Max. Mild Steel Coil Weight | 26.8 t |
| Max. Stainless Steel Coil Weight | 26.0 t |
5. Mill Stand Data
The mill consists of E1, R1, S1 and F1–F3. Different work roll, backup roll and drive configurations are adopted for each stand to meet the requirements of different rolling stages.
Main Stand Specifications:
| Stand | Work Roll Diameter | Backup Roll Diameter | Roll Barrel Length | Motor Power | Max. Rolling Force |
|---|---|---|---|---|---|
| E1 | Φ1150/1050/650 mm | — | 650 mm | 2×1500 kW (DC) | 7,000 kN |
| R1 | Φ1200/1100 mm | Φ1600/1450 mm | 1780 mm | 2×7000 kW (AC) | 45,000 kN |
| S1 | Φ760/690 mm | Φ1600/1450 mm | WR: 2080 mm; BUR: 1780 mm | 1×14000 kW (AC) | 50,000 kN |
| F1 | Φ700/630 mm | Φ1600/1450 mm | WR: 2080 mm; BUR: 1780 mm | 7000 kW (AC) | 40,000 kN |
| F2 | Φ700/630 mm | Φ1600/1450 mm | WR: 2080 mm; BUR: 1780 mm | 7000 kW (AC) | 40,000 kN |
| F3 | Φ700/630 mm | Φ1600/1450 mm | WR: 2080 mm; BUR: 1780 mm | 7000 kW (AC) | 40,000 kN |
Note: WR refers to Work Roll, and BUR refers to Backup Roll.
(1) E1 Edger
The E1 edger is installed in the R1 roughing mill area and is mainly used for slab width control through side reduction.
The equipment adopts AWC (Automatic Width Control) and SSC (Short Stroke Control) configurations.
Main technical specifications:
Motor configuration: 2×1500kW DC motors.
Maximum rolling force: 7,000kN.
Maximum side reduction: 80mm/pass (for 200mm carbon steel slabs).
(2) R1 4-Hi Reversing Roughing Mill
The R1 roughing mill adopts a four-high reversing rolling configuration and is responsible for the initial rolling and thickness reduction of reheated slabs.
The mill is equipped with a hydraulic AGC system and work roll bending functions to support thickness adjustment and rolling control during the roughing process.
Main technical specifications:
Mill type: 4-Hi Reversing Mill.
Main motors: 2×7000kW AC motors.
Maximum rolling force: 45,000kN.
Maximum reduction per pass: 50mm.
Maximum speed: 6.28m/s.
Work roll bending force: +1,800kN/chock.
Thickness control: Hydraulic AGC.
Control configuration: APC+AGC.
(3) S1 4-Hi Reversing Steckel Mill
The S1 is the core rolling equipment of the production line. It adopts a four-high reversing rolling configuration and is equipped with coiler furnaces at both the entry and exit sides.
Through repeated reversing rolling, the S1 further reduces the thickness of the transfer bar. The entry and exit coiler furnaces support strip coiling and temperature maintenance during multi-pass rolling operations.
Main technical specifications:
Mill type: 4-Hi Reversing Mill.
Main motor power: 1×14,000kW AC motor.
Maximum rolling force: 50,000kN.
Maximum rolling speed: 10.0m/s.
Work roll bending force: 1,800kN/chock.
Work roll shifting: ±150mm.
Configuration: Entry and exit coiler furnaces.
(4) F1–F3 4-Hi Finishing Mills
The finishing mill group consists of three 4-Hi finishing stands, F1, F2 and F3. These stands are responsible for further thickness reduction and final thickness control of the strip after Steckel rolling.
All three stands adopt a four-high configuration and are equipped with work roll bending and work roll shifting functions to meet the adjustment requirements during finishing rolling.
Main technical specifications:
Mill type: 4-Hi Finishing Mill.
Number of stands: 3.
Motor power per stand: 7,000kW.
Maximum rolling force: 40,000kN.
Work roll shifting: ±150mm.
Maximum work roll speed of F1: 13.19m/s.
Maximum work roll speed of F2 and F3: 11.93m/s.
Mill type: 4-Hi HCW.
6. Production Process Flow
The production line adopts a complete hot rolling process, including slab charging, reheating, descaling, rough rolling, Steckel rolling, finishing, laminar cooling, coiling and finished coil inspection.
Production Process:
Continuous Cast Slabs → Cold Charging (CCR) / Hot Charging (HCR) → Weighing → Walking-Beam Reheating Furnace → High-Pressure Water Rough Descaling → E1 Edger + R1 Reversing Roughing Mill → Drum-Type Crop Shear → High-Pressure Water Finish Descaling → S1 Steckel Mill (with Entry and Exit Coiler Furnaces) → F1–F3 Finishing Stands → Laminar Cooling → Underground Downcoiler → Binding → Offline Coil Inspection and Marking → Finished Hot-Rolled Coils.
7. Major Auxiliary Equipment Configuration
(1) Walking-Beam Reheating Furnace
The production line is equipped with one walking-beam reheating furnace, which heats the incoming slabs to the temperature required for subsequent rolling operations.
The furnace supports both cold charging (CCR) and hot charging (HCR), allowing different charging methods according to slab production and handling conditions.
Main specifications:
Quantity: 1 unit.
Standard slab size: 200×11,000mm.
Maximum slab weight: 27.6 tons.
Charging method: Cold Charging / Hot Charging.
(2) Rough Descaling Box
The rough descaling box is used to remove the iron oxide scale formed on the slab surface during reheating, providing a cleaner surface for subsequent rough rolling.
The equipment adopts high-pressure water descaling to remove surface scale through high-pressure water spraying.
Main specifications:
Quantity: 1 unit.
Nozzle pressure: 28–30MPa.
Spray headers: 2 pairs, 4 headers in total.
Spray width: 1,770mm.
(3) E1 Edger
The E1 edger is installed in the R1 roughing mill area and is mainly used for slab width adjustment through side reduction.
Main specifications:
Quantity: 1 unit.
Maximum side reduction: 80mm/pass (for 200mm carbon steel slabs).
(4) R1 4-Hi Roughing Mill
The R1 roughing mill performs the initial rolling and thickness reduction of slabs. It adopts a four-high reversing configuration and is equipped with work roll bending and hydraulic AGC systems.
Main specifications:
Quantity: 1 unit.
Maximum speed: 6.28m/s.
Work roll bending force: +1,800kN/chock.
Thickness control: Hydraulic AGC.
Maximum reduction per pass: 50mm.
(5) Drum-Type Crop Shear
The drum-type crop shear is used to cut the head and tail ends of the transfer bar after rough rolling, preparing the strip for subsequent rolling operations.
Main specifications:
Quantity: 1 unit.
Cutting force: 9,600kN.
Shear speed: 0.6–2.0m/s.
Main motor power: 1,600kW (DC).
(6) Finish Descaling Box
The finish descaling box adopts high-pressure water descaling and is installed before the Steckel mill to further remove iron oxide scale from the transfer bar surface.
Main specifications:
Quantity: 1 unit.
Nozzle pressure: 28–30MPa.
Spray headers: 2 pairs, 4 headers in total.
Spray width: 1,770mm.
Type: Pinch-roll type high-pressure water descaler.
(7) Entry and Exit Coiler Furnaces
Two coiler furnaces are installed at the entry and exit sides of the Steckel mill.
They are mainly used for strip coiling and temperature maintenance during reversing rolling operations, helping maintain the required temperature conditions during multi-pass rolling.
Main specifications:
Quantity: 2 units.
Installation position: Entry and exit of the S1 Steckel mill.
Maximum furnace temperature: 1,150°C.
(8) S1 Steckel Mill
The S1 is a 4-Hi reversing Steckel mill, responsible for further rolling and thickness reduction of the transfer bar.
Main specifications:
Quantity: 1 unit.
Maximum rolling speed: 10.0m/s.
Work roll bending force: 1,800kN/chock.
Work roll shifting: ±150mm.
(9) F1–F3 Finishing Mills
The finishing mill group consists of three 4-Hi finishing stands, responsible for final strip rolling and thickness control.
Main specifications:
Quantity: 3 units.
Work roll bending configuration.
Work roll shifting: ±150mm.
Maximum work roll speed of F1: 13.19m/s.
Maximum work roll speed of F2 and F3: 11.93m/s.
Hydraulic loopers installed between S1 and F1–F3.
(10) Laminar Cooling System
The laminar cooling system is installed downstream of the finishing mills and is mainly used to cool the rolled strip to the required temperature before coiling.
The system works together with the finishing mills and downcoiler to complete the cooling stage of the hot rolling process.
(11) Underground Downcoiler
The equipment is equipped with one fully hydraulic underground downcoiler, featuring a three-wrapper-roll configuration and an AJC control system.
The downcoiler is used to wind the strip after finishing rolling and laminar cooling into finished hot-rolled coils.
Main specifications:
Quantity: 1 unit.
Drive type: Fully hydraulic.
Number of wrapper rolls: 3.
Control system: AJC.
Coiling temperature: 550–750°C.
Maximum coiling speed: 14.5m/s.
Mandrel diameter: Φ762 (expanded) / Φ745 / Φ727mm.
Coil outer diameter: Φ1,000–1,900mm.
Maximum coil weight: 26.8 tons.
8. Electrical and Hydraulic Systems
(1) Electrical Control System
The equipment is equipped with an electrical control system that provides control support for the main mill drives, auxiliary equipment and overall production line operation.
According to the original equipment documentation, the on-site electrical control system is in good condition. The electrical control cabinets and related control equipment are also documented in the equipment inspection photographs.
(2) Hydraulic System
The production line is equipped with hydraulic stations and related hydraulic control equipment, providing power for mill screw-down, work roll bending, coiling and other hydraulic actuators.
The original equipment documentation includes photographs of the on-site hydraulic stations and related equipment.
(3) Transformers
The equipment is supplied with supporting transformers. According to the original documentation, all transformers are in good condition.
9. Spare Parts Configuration
According to the original equipment documentation, the equipment includes online and standby roll spare parts.
| Item | Configuration |
|---|---|
| Roll Spare Parts | 1 set online |
| Standby Rolls | 1 set standby |
10. Key Equipment Features
High Annual Production Capacity: Features an annual designed capacity of 1.2 million tons with an overall yield of approximately 97%, suitable for large-scale hot-rolled strip production.
Wide Range of Steel Grades: Suitable for 201, 304, 316, 410S and 430 stainless steels, as well as Q235 and Q345 carbon and low-alloy steels. Additional grades include 304L, 316L and 2205.
Flexible Mill Configuration: Adopts a 1+1+3 configuration, combining an edger, reversing roughing mill, Steckel reversing mill and three finishing stands to meet different rolling process requirements.
Steckel Reversing Rolling Technology: The S1 adopts a 4-Hi reversing configuration with entry and exit coiler furnaces, supporting multi-pass reversing rolling and temperature maintenance during production.
Wide Product Specification Range: Produces carbon steel with thicknesses of 2.0–16.0mm and stainless steel with thicknesses of 2.0–12.0mm, meeting different hot-rolled product specifications.
High-Power Rolling Configuration: The S1 Steckel mill is equipped with a 14,000kW main motor, the R1 roughing mill with 2×7,000kW main motors, and each finishing stand F1–F3 with a 7,000kW motor.
Comprehensive Descaling System: Equipped with rough and finish descaling boxes featuring nozzle pressures of 28–30MPa, helping remove iron oxide scale from slab and transfer bar surfaces.
Complete Cooling and Coiling System: Equipped with a laminar cooling system and a fully hydraulic underground downcoiler, featuring a maximum coiling speed of 14.5m/s and a maximum coil weight of 26.8 tons.
Electrical and Hydraulic Equipment: Equipped with electrical control systems, hydraulic stations and transformers. According to the original documentation, the electrical control system and transformers are in good condition.
