Steel Production Process

1.Roughing Rolling

Slabs are heated inside reheating furnace, then processed by roughing mill to eliminate casting defects. This step shapes raw slab into intermediate material with target thickness range for subsequent finishing rolling.

2.Finishing Rolling

High‑load finishing mill realizes precise thickness reduction. Automatic gauge control and shape control systems minimize thickness deviation and improve flatness, suitable for both general carbon and high‑strength heavy‑gauge plates.

3.Accelerated Cooling

Advanced mist cooling unit delivers uniform temperature gradient across plate width. Controlled accelerated cooling enables high‑strength mechanical performance, which is critical for wear‑resistant plate and structural steel grades.

4.Hot Leveling

Hot leveler removes internal residual stress generated during rolling, correcting plate warpage and delivering flat base material for further processing.

5.Cutting & Slitting

After cooling, plates go through dimension inspection. Materials are cut to custom width and length by mechanical shearing or flame cutting, to match customer order specifications.

6.Heat Treatment & Shot Blasting

For boiler plate, pressure‑vessel plate and weather‑resistant grades, plates proceed with shot blasting for scale removal, followed by quenching and tempering heat‑treatment, to achieve required mechanical property and surface condition.

7.Ultrasonic Inspection

Ultrasonic testing equipment detects blowholes, inclusions, laminations and other internal flaws. Full inspection guarantees internal quality for heavy‑duty engineering application scenarios.

1.Base Substrate Preparation

Cold‑rolled carbon steel coils are selected as base raw material. Base material thickness and width are customized according to final product requirements for GI, GL and PPGI lines. Defective surfaces are pre‑inspected before entering the continuous coating production line to guarantee subsequent coating quality.

2.Continuous Hot‑Dip Galvanizing (GI) / Galvalume Coating (GL)

Cleaned steel strip passes through molten zinc bath for GI galvanizing coating, or aluminum‑zinc alloy bath for GL galvalume coating. Controlled coating weight forms uniform anti‑corrosion metallic zinc or Al‑Zn alloy layer on both sides of steel substrate. After cooling, finished galvanized steel sheet, galvanized steel coil and galvanized strip are produced; similarly, galvalume sheet, galvalume coil and galvalume strip are obtained on this line. GI & GL products can be delivered as flat goods directly or transferred to the painting line for color coating.

3.Surface Pretreatment for PPGI / PPGL

For prepainted products, GI or GL base coils go through surface pretreatment stages including degreasing, alkaline cleaning, chemical conversion treatment. This step removes oil and impurities, improves paint adhesion and prevents peeling of the top organic coating layer.

4.Organic Coating & Curing

Treated GI / GL strip is fed into the continuous painting unit. Primer and topcoat are applied on one‑side or double‑side as per order requirements. Coated strip travels through high‑temperature curing oven to solidify paint film, forming PPGI or PPGL color‑coated steel coil with durable color and weather resistance.

5.Slitting & Shearing for Flat Products

Finished GI, GL and PPGI/PPGL coils can be processed further. Wide mother coils are slit into narrow coated steel strip; coils are sheared into flat coated sheets, delivering flat finished GI sheets, GL sheets and flat color‑coated sheets.

6.Roll‑Forming for Corrugated Roof Panels

Portion of GI, GL and PPGI/PPGL flat coils are sent to roll‑forming equipment. Continuous cold roll forming presses flat coated steel into wave‑shaped profiles, manufacturing galvanized corrugated roofing sheet, galvalume corrugated panel and color‑coated corrugated roof sheet for building roofing and wall cladding projects.

7.Final Inspection & Packaging

All finished goods undergo strict inspection: coating weight testing, paint film thickness check, surface appearance observation, dimension measurement, and corrugation profile verification for roofing panels. Qualified galvanized, galvalume and color‑coated flat & profiled products are properly packaged for global logistics and delivery.

1. Smelting & Continuous Casting

High-purity molten steel blended with precise silicon content is smelted in specialized furnaces. Strict chemical composition control is implemented to meet the material standards for CRGO grain-oriented and CRNO non-oriented silicon steel. Qualified molten steel is continuously cast into standard silicon steel slabs, providing qualified raw slabs for subsequent rolling production.

2. Hot Rolling & Normalizing

The silicon steel slabs are heated uniformly and processed through multi-pass hot rolling to form hot-rolled silicon steel coils. Targeted normalizing treatment is carried out to refine internal grain structure, eliminate rolling residual stress, and optimize material plasticity, laying a foundational quality guarantee for fine cold rolling and magnetic property formation.

3. Pickling & Surface Cleaning

Hot-rolled base coils undergo professional acid pickling and surface polishing treatment to completely remove surface oxide scale and impurities. This process ensures a clean and flat steel surface, avoiding surface defects and performance impacts on finished silicon steel plates and coils.

4. Precision Cold Rolling

According to different product types, differentiated cold rolling processes are adopted. CRNO non-oriented silicon steel base materials are rolled to uniform thickness with fine grain dispersion; CRGO grain-oriented silicon steel undergoes precise multi-pass cold rolling to form regular oriented grain arrangement, ensuring excellent directional magnetic conductivity of finished products.

5. Specialized Annealing Treatment

Two targeted annealing processes are applied for classification production. CRNO non-oriented silicon steel adopts recrystallization annealing to achieve uniform and stable magnetic properties in all directions. CRGO grain-oriented silicon steel undergoes high-temperature grain-oriented annealing to induce regular grain orientation, effectively reducing iron loss and improving magnetic induction efficiency.

6. Insulating Coating & Curing

The surface of annealed silicon steel plate and coil is coated with high-performance insulating paint uniformly. After high-temperature curing, a dense, wear-resistant and insulating protective film is formed on the steel surface, which effectively isolates electrical conduction and meets the insulation requirements of electrical equipment.

7. Slitting & Shearing Finishing

Finished silicon steel mother coils are precisely processed according to customer specifications. Wide coils can be slit into narrow specification silicon steel coils or cut into standard flat plates, realizing customized production of CRGO grain-oriented silicon steel plate/coil and CRNO non-oriented silicon steel plate/coil.

8. Performance Testing & Finished Inspection

Strict professional tests are conducted on finished products, including iron loss detection, magnetic induction testing, dimensional tolerance inspection and surface quality checking. All qualified CRGO and CRNO silicon steel plates and coils are packaged and delivered for global electrical industry applications.

1.Melting & Continuous Casting

Raw alloy materials including chromium, nickel and steel scrap are melted in electric‑arc furnace. Molten stainless steel is continuously cast into stainless steel slabs and billets, controlling chemical composition strictly to meet different grade requirements such as 304, 316L, 201, 430. This cast slab acts as the starting raw material for subsequent hot rolling.

2.Hot Rolling

Heated stainless slabs enter the hot‑rolling mill for multi‑pass thickness reduction. After hot rolling, materials can be output as hot‑rolled stainless steel plate, or coiled into hot‑rolled stainless steel coil. Hot‑rolled coils are the base feedstock for further cold rolling and precision strip production.

3.Hot Annealing & Pickling

Hot‑rolled plate and coil go through high‑temperature annealing to eliminate rolling stress, followed by pickling and descaling to remove surface oxide scale. This step achieves clean metallic surface and optimizes material ductility for downstream cold working.

4.Cold Rolling

Hot‑rolled pickled coils are fed into cold rolling mill. Multi‑pass cold rolling reduces thickness further, improves surface finish and dimensional accuracy. From this procedure, materials branch into two directions: conventional cold‑rolled stainless steel plate & coil, and feedstock for precision stainless steel strip.

5.Precision Rolling (for Precision Strip)

For stainless precision strip, additional multi‑stand precision cold rolling is implemented to achieve ultra‑tight thickness tolerance, narrow width specification and smooth surface. This dedicated process is exclusive for thin‑gauge precision strip used in high‑precision industrial components.

6.Final Annealing & Bright Treatment

Cold‑rolled plate, coil and precision strip receive final annealing to adjust hardness and mechanical property. Options include bright annealing for bright surface or conventional annealing plus pickling for matte finish, depending on customer surface requirements such as 2B, BA, No.1 finish.

7.Cutting, Slitting & Edging

According to order specifications, stainless plate is cut to custom length; stainless coil can be slit into narrow width coils; precision strip goes through precision edging to remove burrs. This step converts wide mother coils into finished plate, standard coils and narrow precision strip.

8.Inspection & Testing

Full range inspection includes dimension tolerance check, surface visual inspection, hardness test and chemical composition verification. Key products for heavy‑duty usage will complete ultrasonic inspection. Qualified stainless steel plate, coil and precision stainless steel strip are prepared for global shipment.