Preheater Inner Cylinder
Heat-resistant steel inner cylinders for cement plant suspension preheaters (Stage 4-5). Engineered for high-velocity gas flow and abrasive raw meal separation. Temperature rating 1000-1050 C
Preheater Inner Cylinder
Material Specifications & Selection Guide
| Grade | Standard | Max Temp | Key Feature | Application |
|---|---|---|---|---|
| ZG35Cr24Ni7SiN | GB/T 8492 | 1050 C | Nitrogen-strengthened, high creep & abrasion resistance | Stage 4-5 inner cylinders, high-temp dip tubes |
| ZG40Cr25Ni12Si2 | GB/T 8492 | 1000 C | Excellent oxidation resistance, balanced performance | Stage 3-4 inner cylinders, standard service |
| ZG30Cr26Ni5 | GB/T 8492 | 950 C | Good thermal shock resistance, cost-effective | Stage 2-3 cylinders, lower-temp applications |
| ZG40Cr25Ni20Si2 | GB/T 8492 | 1050 C | Superior oxidation resistance, highest Ni content | Stage 5 hot zone, heavy-duty inner cylinders |
| ZG30Cr20Ni10 | GB/T 8492 | 900 C | Economical, good general heat resistance | Stage 1-2 cylinders, top-stage applications |
| Grade | C (%) | Cr (%) | Ni (%) | Si (%) | Mn (%) | N (%) | P/S Max |
|---|---|---|---|---|---|---|---|
| ZG35Cr24Ni7SiN | 0.30-0.40 | 23.0-26.0 | 6.0-8.0 | 1.30-2.00 | 0.50-1.50 | 0.15-0.25 | 0.040 |
| ZG40Cr25Ni12Si2 | 0.35-0.45 | 24.0-27.0 | 11.0-14.0 | 1.50-2.50 | 0.50-1.50 | – | 0.040 |
| ZG30Cr26Ni5 | 0.25-0.35 | 24.0-28.0 | 4.0-6.0 | 1.00-2.00 | 0.50-1.50 | – | 0.040 |
| ZG40Cr25Ni20Si2 | 0.35-0.45 | 24.0-27.0 | 19.0-22.0 | 1.50-2.50 | 0.50-1.50 | – | 0.040 |
| Grade | Tensile (MPa) | Yield (MPa) | Elong. (%) | Hardness (HBW) | Creep 1000 C (MPa) |
|---|---|---|---|---|---|
| ZG35Cr24Ni7SiN | 480 | 245 | 8 | 170-220 | 18 |
| ZG40Cr25Ni12Si2 | 440 | 220 | 6 | 180-230 | 12 |
| ZG30Cr26Ni5 | 450 | 235 | 10 | 170-220 | 10 |
| ZG40Cr25Ni20Si2 | 450 | 235 | 8 | 180-240 | 15 |
Selection Quick Reference
- Stage 5 (hottest, 950-1050 C): ZG35Cr24Ni7SiN — nitrogen-strengthened for maximum creep resistance and erosion resistance in high-velocity gas streams
- Stage 4 (hot, 850-950 C): ZG40Cr25Ni20Si2 — superior oxidation resistance for sustained high-temperature exposure with heavy dust loading
- Stage 3 (medium, 750-850 C): ZG40Cr25Ni12Si2 — balanced cost and performance, standard choice for mid-stage preheater cylinders
- Stage 1-2 (cooler, 550-750 C): ZG30Cr26Ni5 or ZG30Cr20Ni10 — economical grades with adequate properties for top-stage conditions
- All grades compatible with FLSmidth, KHD, Polysius, Sinoma, IKN preheater designs
Certifications & Authorizations
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Custom OEM / ODM
From drawing to delivery — one-stop customization, no minimum order
Send Drawing
Upload your technical drawing (PDF, DWG, STEP, IGES) or share sample photos with dimensions
Engineering Review
Material recommendation, casting process design, DFM analysis — free quotation within 24 hours
Sampling & Test
Prototype production with full inspection: hardness test, spectrometer, dimensional check
Production & Ship
ISO 9001 certified. 15-25 days standard lead time. Global shipping with full documentation
Frequently Asked Questions
The inner cylinder is the most critical wear component in a preheater cyclone. Its function is to guide the gas-solid separation process: hot gases exit upward through the inner cylinder while separated raw meal particles fall into the cyclone cone for transfer to the next stage.
Three failure modes:
- Erosion wear (most common): High-velocity gas streams carrying abrasive raw meal particles continuously scour the inner cylinder walls. Wear rates of 2-5 mm/year are typical. The lower third of the cylinder sees the highest erosion.
- Thermal deformation: Uneven temperature across the cylinder causes warping. A distorted inner cylinder disrupts the cyclone separation vortex, reducing preheater efficiency by 5-10%.
- Support structure failure: Mounting brackets and support rings are stress concentration points. Overheating or mechanical fatigue at these points causes detachment or cracking.
Wear armor tip: For high-erosion areas, we can add hardfacing weld overlay (Stellite 6 or similar) on the lower section to extend life by 40-60% without upgrading the entire casting grade.
To manufacture an exact-fit replacement inner cylinder, please provide the following measurements or documentation:
- Cyclone dimensions: Cyclone internal diameter (D), cylinder insertion depth (H), and vortex finder diameter. These determine cylinder OD, length, and wall angle.
- Inner cylinder dimensions: Outer diameter, wall thickness, total height, number of segments, and segment joint design (flanged, welded, or interlocking).
- Support bracket details: Number of support arms, bracket width/spacing, bolt pattern, and attachment method (bolted vs welded).
- Split design: One-piece or segmented? 2-piece clamshell or 3-piece? This impacts casting mold design and installation logistics.
No drawings available? We can reverse-engineer from your worn inner cylinder. Our metrology lab uses 3D laser scanning to capture exact geometry including wear patterns. Reverse engineering adds 3-5 days to lead time.
Material selection depends on the preheater stage, operating temperature, and gas dust loading. Here’s our field-validated grade-to-stage mapping:
Typical service life by stage (with ZG35Cr24Ni7SiN grade):
Key decision factors: For Stage 5, ZG35Cr24Ni7SiN (N-strengthened) is recommended — the nitrogen addition increases creep strength by 20-30% vs ZG40Cr25Ni12Si2 at the same Cr level. For high chlorine or alkali vapor environments in alternative fuel kilns, consider upgrading to ZG40Cr25Ni20Si2 for better corrosion resistance.
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