Steel Melting & Refinary Works 01

Standard Process for Stainless Steel Production

I. Raw Materials Preparation
    •Scrap Steel: Primary source, with controlled composition and impurities.
    •Ferro-Nickel (Fe-Ni), Ferro-Chrome (Fe-Cr): Alloy additions providing Ni and Cr content.
    •Other Alloying Elements: Such as Mo, Ti, Nb, Cu, N, etc., added according to the steel grade requirements.


II. Melting & Refining

Route 1: Scrap-based Production
    1.Induction Furnace (IF)
    •Melts scrap steel and makes preliminary composition adjustments.
    2.AOD Furnace (Argon Oxygen Decarburization)
    •Argon and oxygen blowing reduces carbon content while minimizing chromium oxidation loss.
    3.VOD Furnace (Vacuum Oxygen Decarburization, optional)
    •Further decarburization under vacuum, suitable for low-carbon and ultra-low-carbon stainless steels (e.g., 304L, 316L).
    4.Ladle Furnace (LF)
    •Secondary refining stage for fine-tuning temperature, composition, and removing inclusions.

Route 2: Fe-Ni + Scrap + Fe-Cr Based Production
    1.Direct AOD Smelting
    •Uses Fe-Ni, Fe-Cr, and scrap as the main charge, with lime and dolomite as flux.
    •Oxygen + argon mixed blowing achieves decarburization and alloying.
    2.Ladle Furnace (LF)
    •Further refining and composition adjustment.


III. Secondary Refining (Optional)
    •VOD Furnace (if not applied earlier): For further reduction of carbon, nitrogen, and hydrogen.
    •RH Furnace (Vacuum Degassing): Applied to certain high-end grades for deep degassing.


IV. Continuous Casting
    •Refined molten steel is cast into semi-finished products:
    •Slab → for hot-rolled and cold-rolled plates
    •Bloom → for bars and wire rods
    •Round billet → for seamless pipes


V. Further Processing
    •Hot Rolling: Rolling billets into plates, bars, or wire rods.
    •Cold Rolling: Enhancing precision and surface quality.
    •Solution Annealing: Improving corrosion resistance and toughness.
    •Pickling: Removing oxide scale for a clean surface finish.


VI. Standardized Process Flow

Process A (Scrap Route)
Scrap Steel → Induction Furnace (IF) → AOD → VOD (optional) → LF → Continuous Casting → Hot/Cold Rolling → Final Products

Process B (Fe-Ni + Fe-Cr Route)
Fe-Ni + Scrap + Fe-Cr → AOD → LF → Continuous Casting → Hot/Cold Rolling → Final Products


This represents a complete standard stainless steel production process.