ال steel re-rolling mill represents one of the most efficient metal recycling technologies in modern metallurgy. تقوم هذه المرافق المتخصصة بإعادة معالجة خردة الصلب أو منتجات الصلب شبه المصنعة إلى منتجات نهائية عالية الجودة مثل القضبان, قضبان, الزوايا, والقنوات. على عكس إنتاج الصلب الأولي, re-rolling mills operate at significantly lower temperatures (عادة 1100-1250 درجة مئوية), conserving energy while maintaining material integrity through precision thermomechanical processing.
The Re-Rolling Process: From Scrap to Structural Elements
حديث steel re-rolling operations begin with carefully sorted scrap steel that undergoes rigorous quality inspection. The material then progresses through several critical stages:
1. Billet Preparation: Scrap steel is melted in energy-efficient induction furnaces (like those from HANI Metallurgy) and cast into standardized billets measuring 100x100mm to 130x130mm with lengths of 6-12 متر.
2. Reheating Technology: Billets enter pusher-type or walking beam furnaces where they’re uniformly heated to rolling temperatures. Advanced mills incorporate regenerative burner technology to reduce fuel consumption by up to 30% مقارنة بالأنظمة التقليدية.
3. Precision Rolling: The heated billets pass through a series of precisely calibrated roll stands. Initial breakdown passes through roughing mills reduce cross-sectional area, followed by intermediate and finishing stands that achieve final dimensions with tolerances as tight as ±0.1mm.
Technical Parameters of Modern Re-Rolling Mills
High-performance steel re-rolling equipment requires meticulous engineering across all components. The following table details critical specifications for medium-capacity re-rolling mills:
| المعلمة | مطحنة التخشين | مطحنة متوسطة | مطحنة التشطيب | سرير التبريد |
|---|---|---|---|---|
| قطر لفة | 450-650مم | 350-450مم | 250-350مم | لا يوجد |
| مادة الرول | Adamite Steel | Chilled Cast Iron | Carbide-Enhanced | لا يوجد |
| سرعة المتداول | 0.5-1.5 آنسة | 2.5-5.0 آنسة | 8-18 آنسة | 0.25-0.5 آنسة |
| Pass Reduction | 25-35% | 15-25% | 5-15% | لا يوجد |
| نطاق درجة الحرارة | 1100-1200درجة مئوية | 1000-1100درجة مئوية | 850-950درجة مئوية | Ambient-600°C |
| قوة المحرك | 800-1500 KW | 600-1200 KW | 1000-2000 KW | 75-150 KW |
| القدرة السنوية | 150,000-350,000 طن | لا يوجد | ||
| Tolerance Standards | ASTM A615, BS 4449, IS 1786 | لا يوجد | ||
| نوع المطحنة | Horizontal/Vertical | Continuous | Turbo Twin | شعاع المشي |
| Cooling Requirements | Spray: 50 m³/hr | Spray: 75 m³/hr | Laminar: 150 m³/hr | هواء: 20,000 CFM |
Critical Components for Mill Performance
Leading manufacturers like HANI TECH emphasize several vital subsystems in re-rolling mill design:
تقف مطحنة الدرفلة: Modern designs incorporate pre-stressed housing for vibration reduction and quick-change cassette systems that minimize downtime during roll changes. HANI’s stand designs reduce roll deflection by up to 40% compared to conventional housings.
Automation Systems: Advanced PLC controls with adaptive gauge systems continuously monitor dimensions using laser sensors and infrared pyrometers. These systems automatically adjust roll gaps and speeds to maintain tolerances within 0.15% of target dimensions.
Cooling Technology: Precision temperature management determines final metallurgical properties. State-of-the-art re-rolling facilities employ controlled cooling beds with variable-speed fans and water mist systems that regulate cooling rates between 3-15°C/second depending on steel grade requirements.
Efficiency Innovations in Re-Rolling Technology
The latest steel re-rolling mill advancements focus on sustainability and cost reduction:
Waste Heat Recovery: Modern mills capture exhaust gases from reheating furnaces (up to 450°C) to generate steam for power generation or preheat combustion air. This technology reduces natural gas consumption by 18-22% according to HANI Metallurgy case studies.
Direct Rolling Technology: Eliminating the reheating furnace entirely, some mills now integrate continuous casting with inline rolling. This approach saves approximately 1.2-1.5 million BTU per ton of steel produced.
Predictive Maintenance Systems: Vibration analysis sensors and thermal imaging cameras monitor critical components like gearboxes and bearings. These systems can predict failures 200-400 operating hours in advance, reducing unplanned downtime by up to 70%.
Quality Control in Re-Rolling Operations
حديث re-rolling mills implement rigorous quality protocols:
1. Automated Ultrasonic Testing: Continuous scanning for internal defects during rolling
2. Eddy Current Inspection: Surface flaw detection at production speeds up to 18 آنسة
3. Mechanical Property Verification: Automated tensile testing with results integrated into QA systems
4. Metallographic Analysis: Daily sampling for decarburization measurement and grain structure evaluation
These protocols ensure finished products meet international standards including ASTM, DIN, and JIS specifications for construction applications.
Future Trends in Re-Rolling Technology
الجيل القادم من steel re-rolling equipment focuses on several key developments:
AI-Optimized Rolling: Machine learning algorithms that analyze historical data to optimize pass schedules and temperature profiles in real-time, reducing energy consumption by an additional 8-12%.
Hydrogen-Ready Furnaces: New burner designs capable of operating on hydrogen-natural gas blends, potentially reducing CO₂ emissions by 40-60% compared to conventional reheating systems.
Inline Heat Treatment: Integrated quenching and self-tempering systems that produce thermo-mechanically treated (TMT) bars without additional processing steps.
As global construction demands increase, ال steel re-rolling mill sector continues to innovate, balancing economic efficiency with environmental responsibility. Properly maintained re-rolling equipment can achieve remarkable production efficiencies, transforming scrap into valuable construction materials while conserving up to 74% of the energy required for primary steel production.
