FH® Pit /Well-type Furnace Base Tray
Key Benefits
- Heavy-Load Bearing Capacity
Reinforced rib structure and strategically placed support feet
distribute weight evenly – supports tall stacks of parts or
multiple baskets without center sagging. - High Creep Strength Material
1.4849, 310S, 2.4879 or 1.4828 heat-resistant alloys maintain
dimensional stability at 850–1050°C – no progressive deformation
over hundreds of cycles. - Gas Circulation Optimized
Raised feet create a gap between tray and furnace bottom – allows
hot gas or atmosphere to flow under the lowest layer for uniform
heating. - Anti-Carburization / Anti-Nitriding
High-silicon alloys (1.4849 / 1.4828) resist carbon and nitrogen
penetration – extends service life in aggressive atmospheres. - Custom Shape & Size
Circular or rectangular – precisely matched to your furnace
internal diameter or dimensions. Segmented options for large
diameters.
Technical Specifications
| Parameter | Value |
| Typical materials | 1.4849, 310S, 2.4879 (by specification) |
| Max. continuous temp. | 1100°C (1.4849) / 1000°C (310S) / 1200°C (2.4879) |
| Shape | Circular (standard) or rectangular |
| Support feet height | 50 – 200 mm (custom) |
| Grid pattern | Open grid / perforated plate / cast solid |
| Max. load | 500 – 3000 kg (design dependent) |
| Fabrication | Precision welding or investment casting |
| Standard diameters | 600 mm, 800 mm, 1000 mm, 1200 mm (custom available) |
| Expected service life | 300 – 600 cycles (depending on material & atmosphere) |
| Material test certificate (MTC) included with every FH® base tray |
Why Choose FH® Pit/ Well-type Furnace Base Trays?
1. The Foundation of Your Entire Load
The base tray supports everything above it. If it sags, cracks, or
fails, the entire batch is compromised – parts may tip, baskets may
bind, and heating becomes uneven. FH® base trays are engineered
specifically for this critical role.
2. Design Features That Matter
| Feature | Benefit |
| Reinforced rib underside | Prevents center sagging under heavy loads |
| Raised support feet | Allows gas flow under bottom layer – uniform heating |
| Smooth top surface | Stable base for stacking baskets |
| Rounded corners (rectangular) | Reduces stress concentration |
| Segmented construction (large diameters) | Easy installation through top opening |
| Pre-oxidized surface | Forms protective oxide layer – reduces scaling |
3. Anti-Carburization = Longer Life
In carburizing furnaces, carbon penetrates and embrittles ordinary
trays. FH® uses:
- High-silicon alloys (1.4828, 1.4849) – silicon forms a barrier
against carbon diffusion
- Pre-oxidation treatment – creates stable Cr₂O₃ / SiO₂ layer
- Smooth surfaces – reduces carbon adhesion and soot buildup
Applications
- Well-type / pit carburizing furnaces
- Well-type annealing furnaces
- Well-type tempering furnaces (medium-high temperature)
- Well-type gas nitriding furnaces (with 310S or 1.4849)
- Parts: large gears, shafts, rings, dies, tooling, long tubes, heavy
castings
Genuine Photos of FH® Pit/ Well-type Furnace Base Trays
Material Grade Table:
| Heat-resistant Steel |
| / | GB | DIN | ASTM | JIS | Chemical Composition (%) | Maximum Operation Temperature |
| C | Si | Mn | Cr | Ni | Nb/Cb | Mo | Other |
| 1 | ZG40Cr27Ni4 | 1.4823 | HD | SCH11 | 0.30 - 0.50 | ≤2.00 | ≤1.00 | 24.00 - 28.00 | 4.00 - 6.00 | - | ≤0.50 | - | 1050℃ |
| 2 | ZG40Cr22Ni10 | 1.4826 | HF | SCH12 | 0.30 - 0.50 | 1.00 - 2.50 | ≤2.00 | 19.00 - 23.00 | 8.00 - 12.00 | - | ≤0.50 | - | 950℃ |
| 3 | ZG30Cr28Ni10 | - | HE | SCH17 | 0.20 - 0.50 | ≤2.00 | ≤2.00 | 26.00 - 30.00 | 8.00 - 11.00 | - | - | - | 1050℃ |
| 4 | ZG40Cr25Ni12 | 1.4837 | HH | SCH13 | 0.30 - 0.50 | 1.00 - 2.50 | ≤2.00 | 24.00 - 27.00 | 11.00 - 14.00 | - | ≤0.50 | - | 1050℃ |
| 5 | ZG30Cr28Ni16 | - | HI | SCH18 | 0.20 - 0.50 | ≤2.00 | ≤2.00 | 26.00 - 30.00 | 14.00 - 18.00 | - | - | - | 1100℃ |
| 6 | ZG40Cr25Ni20Si2 | 1.4848 | HK | SCH21 | 0.30 - 0.50 | ≤1.75 | ≤1.50 | 23.00 - 27.00 | 19.00 - 22.00 | - | ≤0.50 | - | 1100℃ |
| 7 | ZG30Cr20Ni25 | - | HN | SCH19 | 0.20 - 0.50 | ≤2.00 | ≤2.00 | 19.00 - 23.00 | 23.00 - 27.00 | - | - | - | 1100℃ |
| 8 | ZG40Cr19Ni39 | 1.4865 | HU | SCH20 | 0.35 - 0.75 | ≤2.50 | ≤2.00 | 17.00 - 21.00 | 37.00 - 41.00 | - | - | - | 1020℃ |
| 9 | ZG40Cr15Ni35 | 1.4806 | HT | SCH15 | 0.35 - 0.70 | ≤2.00 | ≤2.00 | 15.00 - 19.00 | 33.00 - 37.00 | - | ≤0.50 | - | 1000℃ |
| 10 | ZG40Cr25Ni35Nb | 1.4852 | HPCb | SCH24Nb | 0.30 - 0.50 | ≤2.00 | ≤2.00 | 24.00 - 28.00 | 33.00 - 37.00 | 0.80 - 1.80 | ≤0.50 | - | 1100℃ |
| 11 | ZG40Cr19Ni39Nb | 1.4849 | - | - | 0.30 - 0.50 | 1.00 - 2.50 | ≤2.00 | 18.00 - 21.00 | 36.00 - 39.00 | 1.20- 1.80 | ≤0.50 | - | 1100℃ |
| 12 | ZG40Cr24Ni24Nb | 1.4855 | - | - | 0.30 - 0.50 | 1.00 - 2.50 | ≤2.00 | 23.00 - 25.00 | 23.00 - 25.00 | 0.80 - 1.80 | ≤0.50 | - | 1050℃ |
| 13 | ZG40Cr25Ni35 | 1.4857 | HP | SCH24 | 0.35 - 0.50 | 1.00 - 2.50 | ≤2.00 | 24.00 - 28.00 | 33.00 - 37.00 | - | ≤0.50 | - | 1100℃ |
| 14 | ZG1Cr20Ni32Nb | 1.4859 | - | - | 0.06 - 0.15 | 0.50 - 1.50 | ≤2.00 | 19.00 - 21.00 | 31.00 - 33.00 | 0.50 - 1.50 | ≤0.50 | - | 1050℃ |
| 15 | ZG45Cr12Ni60 | - | HW | - | 0.35 - 0.75 | ≤2.00 | ≤2.00 | 10.00 - 14.00 | 58.00 - 62.00 | - | - | - | 1100℃ |
| 16 | ZG45Cr18Ni66 | - | HX | - | 0.35 - 0.75 | ≤2.00 | ≤2.00 | 15.00 - 19.00 | 64.00 - 68.00 | - | - | - | 1100℃ |
| 17 | ZG1Cr28Co50 | 2.4778 | - | - | 0.05 - 0.25 | 0.50 - 1.00 | ≤1.50 | 27.00 - 30.00 | ≤1.00 | ≤0.50 | ≤0.50 | Co:48.0 - 52.0 | 1200℃ |
| 18 | ZG30Cr28Co50Nb | 2.4779 | - | - | 0.25 - 0.35 | 0.50 - 1.50 | 0.50 - 1.50 | 27.00 - 29.00 | - | 1.50 - 2.50 | ≤0.50 | Co:48.0 - 52.0 | 1200℃ |
| 19 | ZG40Cr28Ni48W5 | 2.4879 | - | SCH42 | 0.35 - 0.55 | 1.00 - 2.00 | ≤1.50 | 27.00 - 30.00 | 47.00 - 50.00 | - | ≤0.50 | W:4.0 - 5.5 | 1200℃ |
Ordering Process
- Provide furnace internal diameter (or length × width) and depth
- Share max load weight and operating temperature
- Specify atmosphere (air, carburizing, endogas, nitrogen, ammonia)
- FH® proposes material grade, grid pattern, foot height, and rib
layout
- Production: 10–20 working days
- Delivery includes: MTC, flatness inspection report, installation
guide
FAQ:
Q1: Why do I need a special base tray for my well-type furnace?
A: Placing baskets directly on the furnace floor blocks gas
circulation under the bottom layer, causing uneven heating. FH®
base trays feature raised feet for gas flow and reinforced ribs to
distribute heavy loads evenly.
Q2: What material do you recommend for a well-type carburizing
furnace at 930°C with 1200 kg load?
A: 1.4849 is our recommendation – best creep strength and
anti-carburization for heavy loads at 930°C. Expected life: 400–600
cycles. 310S would be borderline at that load and temperature.
Q3: How do I clean and maintain the base tray?
A: Every 100–150 cycles, remove tray and lightly bead blast (glass
beads, ≤0.3 MPa). Check flatness – if sag exceeds 5 mm over 1000
mm, consider replacement. Do not hammer or heat-straighten.
Q4: My furnace is 1400 mm diameter. Can you make a one-piece base
tray?
A: For diameters over 1000 mm, we recommend segmented designs (3–4
interlocking pieces) for easier installation through the top
opening. One-piece is possible with side/bottom access.
Q5: What is your warranty?
A: 12 months against manufacturing defects. Normal creep, surface
carburization/nitriding, and gradual sagging are considered wear –
not covered. Every tray comes with MTC and inspection report.
