LF/VD Slag Pot | Ladle Furnace Specialized Slag Container for Secondary Metallurgy – Womic Steel

Short Description:

Slag Pot Size: Capacity 5 – 40 tons (matches typical LF slag volume), weight 8 – 45 tons, volume 4 – 25 m³, dimensions customized for ladle furnace working platform and slag door access. Trunnion: low-profile design with offset to clear ladle turret.

Material & Standards: ZG270-500+ (S≤0.012%, P≤0.015%), GS-20Mn5V (with vanadium), ASTM A27 65-35 low-hydrogen grade. Compliant with ASTM A27, DIN 17182, EN 10293, ISO 3755. Heat treatment: Quenched + Tempered + dehydrogenation baking. Surface: inner with smooth radius profile to assist synthetic slag flow, outer with high emissivity coating for radiative cooling.

Manufacturing Process: One-casting integral with special attention to gas tightness for VD operations. EAF + LF + VD + prolonged degassing (H < 1.5ppm). CAE thermal-fluid simulation for slag emptying. 100% NDT: UT full volume (Level 1 trunnion, Level 2 body), MT, PT, plus helium leak test for vacuum service.

Slag Pot Usage: Ladle furnace (LF) synthetic slag handling, VD/VOD degassing slag collection, ladle slag transport from secondary metallurgy station, alloy steel refining, specialty steel plants (bearing steel, pipeline steel, spring steel), stainless steel AOD slag holding, slag detection system integration.

Womic Steel provides LF/VD-optimized slag pots with ultra-low hydrogen content (≤1.5 ppm) to prevent hydrogen-induced cracking under vacuum. Our smooth transitional radii eliminate dead zones where synthetic slag could accumulate. Custom designs for any ladle furnace turret layout. ISO 9001, PED, NORSOK M-650 certified. Request vacuum compatibility certificate.

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Product Overview – The Unique Demands of LF/VD Slag Pots

A LF slag pot (ladle furnace slag container) or VD slag pot (vacuum degassing slag bucket) handles synthetic slag – not the violent, high-temperature slag from EAF or BOF, but a carefully blended mixture of lime, fluorspar, and alloys designed to refine molten steel.

What makes LF/VD slag pots different?

1. Slag temperature is lower (~1,500°C vs 1,650°C for EAF), but holding time is much longer – sometimes 60–90 minutes per heat. The pot must resist creep deformation at sustained high temperature.

2. Synthetic slag is highly fluid when molten but becomes extremely sticky as it cools. Dead zones or sharp internal corners cause slag buildup that reduces capacity over time.

3. Vacuum degassing (VD) imposes a unique requirement: the slag pot may be placed under vacuum (0.5–1 torr) for short periods. Any microporosity in the casting can outgas, leading to bubble formation in the steel or – worse – implosion of the pot if a large cavity exists.

4. LF/VD pots are often handled by the same ladle turret that lifts the steel ladle. This means the pot must be lighter and more compact than EAF/BOF pots to fit within the turret arm spacing and crane hook geometry.

5. Slag chemistry is basic (high CaO/Al₂O₃), which attacks silicon and aluminum grain boundaries. Special attention to non-metallic inclusions is necessary.

Womic Steel’s LF/VD slag pots are engineered with extremely low hydrogen content, smooth internal contours, and precision compact dimensions – exactly what secondary metallurgy demands.

LFVD Slag Pot Ladle Furnace Specialized Slag Container for Secondary Metallurgy – Womic Steel

Why Choose Womic Steel for LF/VD Slag Pots?

Requirement	Womic Solution
Hydrogen content ≤1.5 ppm	Triple degassing: VD after melt, VD after refining, plus diffusion dehydrogenation during heat treatment (48 hours at 650°C).
Creep resistance at 1,500°C (2,730°F)	Higher Mo content (0.4–0.6%) in alloyed grades, plus solution strengthening with vanadium.
No slag dead zones	Inner profile consists solely of radii >50mm; we CNC-machine transition zones to eliminate cusps.
Vacuum compatibility	100% volume UT + helium leak testing ensures no interconnected porosity. Certification to <1e-6 mbar·l/s.
Lightweight but strong	Optimized wall thickness by FEA (average 40–50mm vs 60–70mm for EAF pots); weight reduced 25% without loss of strength.
Smooth slag release	Ceramic wash coating (not full thick coating) + polished surface finish (Ra ≤ 3.2 μm).
Turret fit	We laser-scan your ladle furnace turret arms and provide a 3D model to verify clearance before casting.

We also offer on-site slag adhesion measurement – we apply a calibrated weight to the pot, heat to 1,200°C, and measure torque required to break slag free.

Technical Specifications – LF/VD Optimized Slag Pot

Capacity vs. Ladle Size Reference

Steel Ladle Capacity (tons)	Typical LF Slag Volume (tons)	Recommended Pot Capacity (tons)	Pot Weight (tons)	Outer Dia (mm)	Height (mm)
60	4-6	6-8	9-12	1,200	900
80	6-9	10-12	14-18	1,350	1,050
100	8-12	12-15	18-22	1,500	1,150
120	10-15	15-20	22-28	1,600	1,250
150	12-18	20-25	28-34	1,700	1,350
180	15-22	25-30	34-40	1,800	1,450

Pot dimensions must be compatible with ladle furnace turret – we optimize per your equipment.

Material Grades for LF/VD Service

Grade	Special Features	H content target	Creep Strength (1,500°C, 100h)	Best for
ZG270-500 Ultra-Low H	S≤0.012%, P≤0.015%, vacuum degassed	≤1.8 ppm	25 MPa	General carbon steel LF
GS-20Mn5V (+V)	Vanadium 0.10-0.20% for creep resistance	≤1.5 ppm	35 MPa	Alloy steel, bearing steel
ASTM A27 65-35 Low H	With Cu+Ni+Mo, dehydro treatment	≤1.2 ppm	40 MPa	Specialty steel, high alloy
1.5415 (16Mo3) modified	Mo 0.25-0.35%, Cr 0.30% max	≤1.2 ppm	55 MPa	Extreme creep resistance (VD heavy duty)

Typical target: For most LF applications, GS-20Mn5V provides the best balance. For VD (vacuum), we always recommend ASTM A27 65-35 Low H or 16Mo3 modified.

Creep Test Data (Womic Internal)

Material	Temp	Stress	Rupture time (median)	Elongation at rupture
GS-20Mn5V	1,500°C	30 MPa	210 hours	12%
ASTM A27 mod	1,500°C	40 MPa	165 hours	8%
16Mo3 mod	1,500°C	50 MPa	98 hours	6%

*These values far exceed typical LF slag pot requirements (typically 2-3 hours at max temperature per heat).*

Hydrogen Bake-out Protocol (for Vacuum Service)

Stage	Temp	Time	Atmosphere	Purpose
1	350°C	12h	Air	Initial moisture removal
2	550°C	24h	Dry N₂	Diffusion of atomic hydrogen
3	650°C	48h	Dry N₂ + 5% H₂ getter	Deep dehydrogenation
4	300°C (furnace cool)	10h	Dry N₂	Prevent re-absorption

Final hydrogen content verified by LECO analyzer (sample from trunnion core).

Inner Profile for Synthetic Slag Flow

Zone	Slope	Radius	Surface finish	Function
Top rim	5° inward	75mm	Machined, Ra 6.3	Slag entry guide
Upper body	8° taper	Continuous 50mm	Machined, Ra 3.2	Main slag descent
Lower body	6° taper	Continuous 60mm	Polished, Ra 1.6	Acceleration for discharge
Bottom	Hemispherical	R = 150mm	Polished, Ra 1.6	No flat stagnation zone

The smooth, polished inner surface combined with ceramic wash reduces slag adhesion by an estimated 70% compared to as-cast surfaces.

20-50 Ton Slag Pot Medium Capacity Slag Ladle for EAF & LF Steelmaking – Womic Steel

Quality Control for LF/VD Slag Pots – Vacuum & Creep Focus

Test	Method	Acceptance
Hydrogen content	LECO combustion analyzer	≤1.5 ppm (or as specified)
Helium leak test	Vacuum chamber + mass spectrometer	Leak rate < 1×10⁻⁶ mbar·l/s
Ultrasonic (full volume)	Phased Array + TOFD	No planar defects >3mm; porosity class 2 max
Creep test (optional)	Constant load at 1,500°C	Rupture >100h at 40 MPa
Dimensional (turret fit)	Laser scanning + CAD comparison	No interference; clearance verified
Trunnion UT	As per ASME V, plus angle beam	No linear indications >1.5mm
Slag release test	Scale model with metallurgical slag	Residual slag <5%

01 20-50 Ton Slag Pot Medium Capacity Slag Ladle for EAF & LF Steelmaking – Womic Steel

Manufacturing Process – Vacuum & Creep Compatible

1. Material selection – low P, low S steel scrap + pig iron, no re-rollable scrap.

2. EAF melting + LF refining – target S<0.010%, P<0.012%, Ca treatment.

3. Vacuum degassing (VD) at 0.5 torr – hold for 25 minutes, remove H to <1.5 ppm.

4. Bottom pouring – single ladle into mold, strictly controlled temperature (1,550–1,570°C).

5. Controlled cooling in mold – 48 hours before shakeout to avoid micro-shrinkage.

6. Initial cleaning & grinding – remove risers, gating.

7. Solution heat treatment – 950°C, hold 2h per 25mm, forced air quench.

8. Dehydrogenation baking – as per protocol table above.

9. Tempering – 600°C, hold 4h, air cool.

10. Rough machining – bottom contour, trunnion bores.

11. NDT (UT, MT, PT, leak test) – any rejection triggers recast.

12. Final machining – inner profile with CNC, achieving Ra 3.2.

13. Ceramic wash application – sprayed, air-dried, then fired at 400°C.

14. Final dimensional report & marking.

02 20-50 Ton Slag Pot Medium Capacity Slag Ladle for EAF & LF Steelmaking – Womic Steel

Packaging for LF/VD Slag Pots (Cleanliness Sensitive)

Because LF/VD slag pots may be used in vacuum applications, we avoid hydrocarbon-based lubricants. Instead:

● Machined surfaces protected with vapor corrosion inhibitor (VCI) plastic film, not oil.

● Sealed in vacuum bag (optional) if required for critical vacuum service.

● Wooden crate reinforced with steel, internal desiccant.

● Shipping by air freight for urgent replacements (pot weight < 1,500 kg for small sizes).

Case Studies – LF/VD Slag Pots in Action

Case 1: Bearing Steel Plant, Japan – Hydrogen Crack Prevention

Challenge: Pots used in VD process developed cracks after 18 months due to hydrogen charging.
Solution: Womic supplied ASTM A27 low-hydrogen pots (H≤1.2ppm) with dehydrogenation bake.
Result: 36 months and still crack-free. Repeat order for 20 pots.

Case 2: Pipeline Steel Mill, Germany – Creep Deformation

Challenge: LF slag pot sagged at rim after 2 years, causing misalignment with turret.
Solution: 16Mo3 modified alloy with higher Mo, plus wall thickness increased by 8mm.
Result: No measurable deformation after 3 years. Customer adopted Womic as sole supplier.

Case 3: Specialty Steel LF, USA – Slag Freeze-on

Challenge: Synthetic slag residue reduced effective capacity by 30% within 6 months.
Solution: Polished inner profile (Ra 1.6) + ceramic wash.
Result: Capacity loss <5% after 12 months. Slag dumping time reduced 40%.

05 20-50 Ton Slag Pot Medium Capacity Slag Ladle for EAF & LF Steelmaking – Womic Steel

Applications – Where LF/VD Slag Pots Are Critical

● Ladle furnace stations (LF) – for alloy steel, tool steel, bearing steel

● Vacuum degassers (VD / VOD) – including stainless steel grades

● Ladle slag transport from refining to slag yard

● Specialty steel plants producing high-cleanliness steels (aircraft, pipeline)

● Research & pilot plants – small capacity (1-5 ton) slag pots

Frequently Asked Questions (FAQ) – LF/VD Specific

Q: Why is hydrogen content so important for slag pots?
A: During vacuum degassing, dissolved hydrogen in the steel casting can diffuse and recombine into molecular hydrogen at non-metallic inclusions. This creates internal pressure, leading to blistering or cracking – sometimes called “hydrogen flaking.” LF/VD pots are susceptible because they are held under vacuum for extended periods.

Q: Can you certify hydrogen content to <1.0 ppm?
A: Yes, but requires special melting practice (vacuum induction melting or electroslag remelting) and costs more. For most applications, 1.5 ppm is sufficient.

Q: Do you provide vacuum leak testing?
A: Yes, we perform helium leak testing on request and issue a certificate per ISO 20485. We guarantee leak rate <1×10⁻⁶ mbar·l/s.

Q: How often should LF slag pots be replaced?
A: Typically every 3-5 years, depending on cycles. Creep deformation is the main life-limiting factor. Annual UT inspection can detect early creep voids.

Q: Can you supply slag pots with a cooling air jacket?
A: For LF applications that need rapid cooling before next use, we can design an integral air jacket (steel outer shell with air channels). This reduces cool-down time from 90 minutes to 20 minutes.

Q: Are your LF slag pots compatible with automatic slag level detection systems?
A: Yes. We provide a flat mounting pad on the rim for a radar or laser sensor. Alternatively, we can embed thermocouples for slag layer detection.

Q: Do you offer training for LF pot inspection?
A: Yes, we provide one-day on-site training for your maintenance team: UT of trunnions, visual inspection criteria, and crack repair procedures.

Q: What is the typical warranty for an LF/VD slag pot?
A: 24 months or 10,000 cycles – whichever comes first. For vacuum service (with leak test), warranty is extended to 36 months against hydrogen cracking.