Product Overview – The EAF Slag Pot Challenge
An EAF slag pot (or electric arc furnace slag ladle) is not just a smaller version of a BOF converter pot. It operates under a completely different set of stressors that make it one of the most demanding castings in a steel mill.
Electric arc furnaces produce slag in batches every 45–90 minutes – often 12 to 20 heats per day. Each cycle involves:
1. Filling with molten slag at 1,600–1,700°C (including metallic droplets)
2. Holding while the pot is transported across uneven floors
3. Dumping via crane tilt, sometimes with impact against a slag pit edge
4. Air cooling to below 300°C before the next filling – creating extreme thermal shock
5. Unlike BOF slag pots that typically receive one slag per shift, EAF pots can be subjected to rapid heating and cooling up to 20 times daily. This high-frequency thermal cycling leads to thermal fatigue cracking – the #1 failure mode for EAF slag pots.
Additionally, EAF slag chemistry varies widely depending on scrap quality, alloy additions, and refining practice. Slag can be ** strongly basic** (high CaO, sticky) or acidic (high SiO₂, fluid). Each requires different inner profile and material response.
Womic Steel has developed EAF-optimized slag pots that address three specific pain points:
● Thermal fatigue cracking – solved by fine-grain steel + controlled cooling heat treatment
● Slag freeze-on – solved by patented double-slope inner contour and anti-stick coating
● Mechanical damage at dumping – solved by reinforced rim and impact-absorbing shape
Why Choose Womic Steel for Your EAF Slag Pot?
| Feature | EAF-Specific Advantage |
| Nb-V Microalloyed Steel | Small amounts of niobium and vanadium pin grain boundaries, delaying thermal fatigue crack initiation. Proven to increase cycles to failure by 70% vs. standard cast steel. |
| Accelerated Quench + Tempered | After austenitizing, forced air (not still air) creates finer pearlite+bainite structure – much higher resistance to thermal shock. |
| Double-Slope Inner Bowl | Upper slope 12°, lower slope 8°, with a 150mm vertical flat zone at tapping impact point. Slag release time reduced by 40% in field tests. |
| ** Anti-Stick Ceramic Coating (Inner)** | Two-part alumina-silicate coating applied 3mm thick, resists basic slag adhesion. Re-application interval exceeds 12 months. |
| Forged Trunnion Option | For pots above 50 tons, we can supply separately forged and assembled trunnions (mechanically locked + full penetration welds) for maximum fatigue life. |
| Dynamic FEA with Heat Check Loading | We simulate 1,000 cycles of 800°C ΔT (heating 300°C→1,600°C, cooling 1,600°C→300°C) to verify no crack initiation. Report included. |
| Low Thermal Expansion Design | Optimized wall thickness gradient reduces thermal stresses in the upper rim zone – the most common crack location. |
| EAF Make Specific Interface | We customize the pot’s upper rim contour to match your furnace slag door opening and tapping spout geometry – no splashing or spillage. |
We also provide a slag pot shuttle inspection program – we train your personnel to perform in-service UT, and we replace pots on a planned cycle, minimizing unplanned downtime.
Technical Specifications – EAF Optimized Slag Pot
Recommended Capacity Range for Common EAF Sizes
| EAF Nominal Capacity (tons) | Slag Volume per Heat (tons) | Recommended Pot Capacity (tons) | Pot Weight (tons) | Daily Cycles (typical) |
| 60 | 12–18 | 15–20 | 12–18 | 15–20 |
| 80 | 16–24 | 20–30 | 18–26 | 15–20 |
| 100 | 20–30 | 30–40 | 26–36 | 12–18 |
| 120 | 25–35 | 40–50 | 36–46 | 12–15 |
| 150 | 30–45 | 50–65 | 46–60 | 10–15 |
| 180 | 40–55 | 65–80 | 60–75 | 8–12 |
Pot capacity should be 1.2–1.5× slag volume to allow foaming slag without overflow.
EAF-Specific Material Grades
| Grade | Microstructure | Thermal Fatigue Resistance | Best for |
| ZG270-500 Modified (Nb 0.03%, V 0.05%) | Fine-grained ferrite/pearlite | +++ | General EAF, cost-effective |
| GS-20Mn5 (1.1120) | Tempered martensite + bainite | ++++ | High power EAF with many cycles/day |
| ASTM A27 65-35 Mod (with Cu+Ni) | Quenched & tempered martensite | ++++ | Stainless steel EAF (corrosive slag) |
| 1.6220 (16MnCr5) | Carburized case + tough core | +++++ | Extreme service >20 cycles/day |
Our Recommendation: For most EAF applications, GS-20Mn5 + quenched & tempered provides the best balance of cost, thermal fatigue resistance, and repairability.
EAF-Specific Dimensional Features
| Feature | EAF Requirement | Womic Steel Design |
| Upper Rim Height | Must be low enough to fit under slag door but high enough to prevent splash-over | Extended front rim (tapping side) 100mm higher than rear rim |
| Trunnion Tilt Angle | 45° tilt for complete emptying | Trunnion axis offset 50mm towards pouring lip – self-draining |
| Bottom Shape | Conical for sticky EAF slag | 120° apex cone with 50mm radius at tip – eliminates slag heel |
| Lifting Lugs | Additional lifting points for maintenance | Four integral lugs for strap slings |
| Drain Hole (optional) | For emptying residual liquid slag before full solidification | 50mm diameter with threaded plug, located at lowest point |
Thermal Fatigue Test Data (Simulated)
| Parameter | Value |
| Testing standard | Womic internal (based on ASTM E606) |
| ΔT per cycle | 1,300°C (300°C → 1,600°C → 300°C) |
| Hold time at max temp | 10 minutes |
| Cooling method | Forced air (simulating actual floor conditions) |
| Cycles to 1mm crack (standard cast steel) | ~1,500 cycles |
| Cycles to 1mm crack (Womic EAF-grade) | ~3,200 cycles |
| Improvement | +113% |
EAF Slag Pot Quality Control – Thermal Cycling Validation
Beyond standard NDT, we perform destructive thermal cycle testing on first-article samples. A smaller test coupon (same heat treatment) is subjected to accelerated thermal cycles in our lab furnace. Cracks are measured via dye penetrant every 500 cycles. The test is terminated when crack length exceeds 3mm. The number of cycles achieved is recorded and guaranteed to meet your minimum requirement (typically 2,500 cycles).
Additional EAF-specific checks:
Wall thickness ultrasonic mapping – we produce a color-coded thickness map of the entire pot, highlighting any below-nominal areas.
Trunnion root radius inspection – using a custom contour gauge, we verify radius = 50mm min.
Rim straightness – after heat treatment, we measure rim flatness; deviation ≤5mm ensures proper fit with slag door.
Manufacturing Process – EAF Duty Cycle Casting
1. Custom Engineering – We analyze your EAF: make, tapping method, slag basicity, cycles per day, crane capacity, and floor layout.
2. FEA Thermal Cycle Simulation – 1,000 virtual cycles identify hot spots; we add ribs or change thickness accordingly.
3. Pattern with EAF Profile – Including the raised front rim and asymmetrical trunnion position.
4. Ultra-Clean Steel – EAF + LF + VD + inert gas shrouded pouring. Target S<0.012%, P<0.015%, H<2ppm.
5. One-Casting – Integral pot + trunnions (or separate forged trunnions for >50 tons).
6. Controlled Solidification – Using exothermic risers only on thick sections; chills near trunnion junctions to avoid shrinkage.
7. Heat Treatment – Quenched (forced air) + Tempered → fine bainitic structure.
8. First UT & MT – Reject any pot with linear defects >2mm.
9. Machine Inner Bowl – CNC machining of the double slope contour.
10. Apply Anti-Stick Coating – Two layers of ceramic, total 2.5–3.0mm DFT, cured at 350°C.
11. Final NDT (Phased Array UT) – Focus on transition zones.
12. Load Test (optional) – With witness, using calibrated load cell at 1.25× rated capacity.
Packaging & Shipping for EAF Slag Pots
EAF pots are often smaller than BOF pots but delivered in higher quantities. We offer:
● Stackable design – with wooden separators, up to 3 pots can be stacked in one 40ft container (saving freight cost).
● Custom steel stillages – for multiple pot shipments, reusable.
● Lead time for first article – 16 weeks (includes pattern and validation test).
● Batch production lead time – 8-10 weeks for additional units.
EAF-Focused Case Studies
Case 1: 80t EAF, Mexican Mini-Mill – Thermal Fatigue Elimination
Problem: Previous pots lasted 9 months (approx. 4,500 cycles) then developed radial cracks at the rim.
Solution: Womic supplied GS-20Mn5 pots with quenched & tempered structure, double-slope inner profile, and anti-stick coating.
Result: After 14 months (7,200 cycles), no visible cracks. Second order for 12 pots placed.
Case 2: 150t DC EAF, South Korean Stainless Mill – Highly Corrosive Slag
Problem: High Cr2O3 slag ate through conventional pots in 6 months.
Solution: Custom alloyed ASTM A27 65-35 with added Cu (0.5%) and Ni (1.0%), plus ceramic coating on entire inner surface.
Result: Service life extended to 18 months – 3× previous. Coated pots also reduced slag freeze-on time by 50%.
Case 3: 60t EAF, Indian Foundry – Frequent Tapping (20+ heats/day)
Problem: Pots cracked within 3 months due to insufficient cooling time between cycles.
Solution: Redesigned pot with thinner wall sections (40mm vs 60mm) plus external cooling ribs to accelerate heat dissipation. Also added forced air cooling station recommendation.
Result: Cracking delayed to 10 months. Lower pot weight also reduced crane wear and tear.
Applications – Where EAF Slag Pots Are Indispensable
● Carbon steel EAF shops (long products, flats)
● Stainless steel EAF melting (highly corrosive slag)
● Alloy steel and tool steel arc furnaces
● Foundry arc furnaces (iron and steel casting)
● Sponge iron / DRI-based steelmaking (high FeO slag)
● EAF dust recycling plants (zinc recovery from EAF dust)
Frequently Asked Questions (FAQ) – EAF Specific
Q: How do I know if my EAF needs a special slag pot?
A: If you run more than 10 heats per day or experience cracks within 12 months on standard pots, you need an EAF-optimized design. Also, if you notice slag sticking excessively or require manual breaking, our anti-stick profile will help.
Q: Can I use the same slag pot for BOF and EAF?
A: Not recommended – EAF pots are designed for faster cycling, thinner walls, and different slag adhesion properties. Using BOF pots in EAF leads to premature cracking; using EAF pots in BOF may overheat them. Always use dedicated pots.
Q: Do you offer financing or pot exchange programs?
A: Yes – we have a slag pot as a service model: you pay per ton of steel produced, and we own and maintain the pots. Minimum 5-year commitment. Ask for details.
Q: What is the typical anti-stick coating lifespan?
A: Under normal EAF operations (basic slag, 15 cycles/day), the coating lasts 9-12 months. Recoating can be done in your plant by our technicians (or we supply coating kit). Lining replacement cost is ~15% of new pot price.
Q: How do you handle emergency replacement if a pot fails suddenly?
A: We keep a small buffer stock (2-4 pots) of common EAF sizes in our warehouse. For customers with service contract, we air-freight within 72 hours.
Q: Can you add temperature sensors to the pot?
A: Yes – we can install thermocouple pockets (up to 4 locations) with Inconel sheathing. Sensors can be connected to a portable monitor or integrated with your plant DCS.
Q: What is the surface finish requirement for EAF slag adhesion?
A: Inner bowl must be machined to Ra ≤ 6.3 μm. As-cast surfaces promote sticking. Our double-slope design combined with fine machining reduces sticking significantly.
Q: How do I clean a slag pot if slag freezes inside?
A: Never use mechanical hammering directly on pot wall – that induces cracks. Instead, use oxygen lancing to cut a channel, then heat the pot evenly. Our anti-stick coating reduces freeze events.
Ready to Improve Your EAF Slag Handling?
Contact Womic Steel for a free thermal fatigue assessment of your current slag pots – we’ll recommend design changes and predict potential service life extension.
Website: www.womicsteel.com
E-mail: sales@womicsteel.com | eaf@womicsteel.com
Tel/WhatsApp/WeChat:
Victor: +86 15575100681
Jack: +86 18390957568
Womic Steel – Engineered for the intense rhythm of electric arc furnace steelmaking.
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