Production Process of Hot Rolled Stainless Steel Plate

The complete production process of hot rolled stainless steel plates follows the sequence: raw material preparation → heating → rough rolling → finish rolling → laminar cooling & coiling → subsequent finishing (annealing / pickling / shearing / inspection). Adhering to exclusive technological standards for stainless steel hot rolling, the process differs significantly from that of ordinary carbon steel.

The primary raw material is stainless steel continuous casting slab, with conventional specifications of 150~220mm in thickness and 1000~2000mm in width.

• Surface Inspection: Check and eliminate surface defects such as cracks, scabs and inclusions.
• Surface Grinding: Polish defective areas to prevent defect expansion during rolling.
• Classified Stacking: Store slabs by material grades (304, 316L, 400 series, duplex steel, etc.) to avoid material mixing.

Stainless steel features poor thermal conductivity and complex alloy elements, requiring strict heating control. A walking beam furnace is widely adopted for production.

• Segmented Heating: Heat slowly at low temperature stages to prevent slab cracking; control temperature and ensure sufficient heat preservation at high temperature stages.
• Temperature Control: 1180~1250℃ for austenitic steel; 1120~1200℃ for ferritic and martensitic steel.
• Heat Preservation: Achieve uniform internal and external slab temperature and reduce rolling resistance.

Core functions: thickness reduction, width spreading and preliminary forming.

• High-pressure Descaling: Remove furnace-scale oxide scales via high-pressure water impact (stainless steel oxide scales are high-hardness and require high-pressure descaling).
• Reciprocating Rolling: The slab undergoes multi-pass reciprocating rolling in the roughing mill unit, processed into intermediate slabs with a thickness of 20~40mm.
• Secondary Descaling: Conduct secondary descaling after each rolling pass to avoid oxide scale indentation and surface pitting defects.

This core process determines the thickness accuracy, plate shape and surface quality of finished plates.

• Constant-temperature Feeding: Deliver intermediate slabs to the finishing mill unit at a constant temperature.
• Multi-pass Continuous Rolling: Adopt a 7-stand continuous rolling unit to reduce thickness pass by pass, producing finished plates with customer-specified thickness (conventional hot rolled plate thickness: 3~80mm).
• Plate Shape Control: Adjust roll bending and roll shifting to ensure flat plate surface and uniform width.

• Uniform Rapid Cooling: Cool the rolled plates evenly through laminar water curtains. The final rolling temperature and cooling rate are precisely controlled for different steel grades to stabilize metallographic structure.
• Coiling: Cool the plates to the specified temperature and coil them intohot rolled steel coils, completing the forming of hot rolled mother coils.

Hot rolled coils cannot be directly used as finished products and require professional post-processing, which also forms different surface states such as 1D and black surface.

Hot rolled stainless steel has work hardening and internal stress, so annealing is mandatory:

• Austenitic steel & duplex steel: Solution annealing to restore corrosion resistance and ductility.
• Ferritic steel & martensitic steel: Softening annealing to improve processing performance.

Main annealing methods: bell annealing and continuous annealing.

Dense oxide layers form on the plate surface after annealing, which are removed via mixed acid pickling (nitric acid + hydrofluoric acid):

• Complete pre-descaling via alkaline washing, followed by acid soaking and spraying;
• Thoroughly rinse with clean water and dry the plates;
• Form a standard 1D (No.1) matte silver-white surface, the mainstream surface of commercial hot rolled stainless steel plates.

Note: Plates without pickling are black surface coils (1U state), only used for deep processing or as cold rolling blanks.

• Flattening & Plate Cutting: Uncoil and flatten hot rolled coils to eliminate coiling radian and form flat plates.
• Fixed-size Shearing: Cut plates according to customized length and width dimensions.
• Edge Processing: Adopt edge cutting (high dimensional accuracy) or reserved hot rolling original edges as required.

• Visual Inspection: Check for surface scratches, pitting, cracks and color difference;
• Dimensional Inspection: Detect thickness, width, length, flatness and edge dimensional accuracy;
• Performance Sampling Test: Verify mechanical properties, metallographic structure and corrosion resistance;
• Marking, Packaging & Warehousing: Complete spray marking, standardized packaging and warehousing management.

• Material Difference: 400-series ferritic and martensitic steel have high high-temperature brittleness, requiring stricter rolling rhythm and cooling speed control than 300-series austenitic steel; duplex steel demands the highest precision in temperature control and rolling reduction.
• Production Form: Manufacturers mainly produce hot rolled coils, which are further processed into flat plates; direct production of single-piece thick plates is rare.
• Product Application: Hot rolled 1D plates are widely used in industrial equipment, storage tanks and structural parts; hot rolled black surface plates are applied in forging and cold rolling blank processing.

We strictly follow standardized hot rolling production processes and implement full-process quality inspection for all stainless steel hot rolled plates. Our products cover complete grades including 304, 316L, 430, 2205 and various specifications, with stable surface quality, accurate dimensions and reliable mechanical properties. They are widely applicable to chemical industry, environmental protection, machinery manufacturing, pressure vessel and other industrial fields. We support customized size processing, wholesale procurement and sample testing. If you have procurement, technical consultation or customized processing needs for hot rolled stainless steel plates, feel free to contact us for factory direct prices and professional technical solutions!

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