Oxide scale is an “invisible loss” in bar and wire rod production—it causes 1%~2% of steel burning loss and triggers multiple pain points such as red rust, surface defects, and environmental pressures from pickling. Below is a refined summary of three core control solutions, focusing on key processes and practical points to help enterprises implement quickly!
🚫 Red Rust Control on Surface: Block “Red Hazards” from the Source
1.Composition risk control: Strictly control Si ≤ 0.08wt% (to avoid forming hard-to-remove Fe₂SiO₄), properly proportion Cr and Ni (reducing oxide scale thickness by 37.5%), and inhibit element segregation.
2. Heating & descaling synergy: Avoid the dangerous temperature range of 1173℃-1220℃, maintain descaling pressure ≥15MPa (incident angle 5°-15°), upgrade nozzles to increase striking force by 15%, and achieve one-time stripping of the FeO layer.
3. Cooling protection: Control Cl⁻ ≤15mg/l and SO₄²⁻ ≤10mg/l in cooling water, adopt dry controlled cooling instead of wet cooling, and precisely control laying temperature (870-920℃ for low-carbon steel / 820-870℃ for high-carbon steel).
4. Heating time optimization: Appropriately extend heating time by 10-15% to increase the growth stress between oxide scale and substrate, improve descaling performance by 30%, and reduce scale indentation.
5. Post-rolling anti-secondary oxidation: Rapidly cool with air to isolate moisture after cooling, prevent FeO from absorbing moisture and oxidizing, and further reduce red rust reoccurrence rate by 20%.
🧪 Easy-Pickling Oxide Scale Control: Improve Pickling Efficiency & Alleviate Environmental Pressure
Core goal: Make oxide scale “easy to strip and low-consumption” to solve pickling pain points.
1. Medium selection: Prioritize hydrochloric acid (reaction rate 30% faster than sulfuric acid) for better adaptability to complex oxide scales; sulfuric acid as a supplement (concentration 15-20%).
2. Structure modification: Promote the eutectoid reaction of FeO (4FeO=Fe+Fe₃O₄), optimize phase ratio (FeO≥50%, Fe₂O₃≤15%), and increase acid penetration efficiency by 50%.
3. Process matching: Control initial rolling temperature at 950-1000℃ (Fe₂O₃ thickness ≤447nm), adopt medium cooling rate (5-20℃/min), and stabilize oxide scale thickness at 20-30um.
4. Pre-pickling pretreatment: Pre-rinse impurities on the oxide scale surface with high-pressure water to reduce acid contamination and further improve pickling efficiency by 15%.
5. Oxidation atmosphere control: Reduce SO₂ and H₂O content in the heating furnace to minimize the formation of low-melting-point oxides such as FeS and avoid molten adhesion of oxide scale.
🔧 Mechanical Stripping Oxide Scale Control: Efficient Desorption & Zero Damage
Core logic: Forced separation by mechanical force, suitable for high surface quality requirements.
1.Composition optimization: Cu (0.028-0.264%) + Ni (0.039-0.081%) reduce the bonding force of oxide scale; low Si and low Cr improve brittleness.
2. Equipment matching: Reverse bending + high-speed roller brush (1000-3000r/min) with tensile deformation of 6%-8%, achieving a stripping efficiency of 98%.
3. Temperature control: Oxidation temperature (860-900℃ for low-carbon steel / 820-860℃ for high-carbon steel), prioritize controlling laying temperature to avoid secondary adhesion.
4. Strengthen equipment maintenance: Regularly inspect roller brush wear and replace rectifier components in a timely manner to ensure uniform striking force and a residue rate ≤3%.
5. Deformation uniformity control: Optimize rolling process to avoid insufficient local deformation, ensuring uniform stripping of oxide scale on the entire surface without residual dead corners.
💡 Core Benefit Summary
If you are facing similar rolling challenges or need in-depth discussion on solutions, feel free to contact us:
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