Steel-Steel Steam Pipe up to 350°C

Overview

Why Steel-Steel Steam Pipes Are the Standard for Buried Steam

Urban steam supply networks and industrial process steam face three challenges: extreme temperatures up to 350°C, high internal stress from thermal expansion, and the need for direct burial without protective concrete ducts. Steel-steel pre-insulated steam pipe solves all three. With multi-layer composite insulation and sliding expansion compensation, these steam pipes deliver 30–50% lower heat loss than traditional on-site rock wool lagging, eliminate concrete encasement costs, and maintain hermetic sealing in groundwater environments.

◆ Dual-Sliding Design — Inner & Outer Options. Every steel-steel steam pipe project faces unique thermal displacement challenges. Inner sliding type places the slip layer near the carrier pipe, with insulation fixed to the outer steel jacket — lower cost, ideal for smaller diameters and straight runs. Outer sliding type attaches insulation to the carrier pipe with the slip surface against the outer jacket — ~22% better thermal efficiency, preferred for larger diameters and complex layouts. We engineer the right sliding type for your steam pipe route geometry.

◆ Multi-Layer Insulation — Glass Wool + PU + Reflective Barrier. Standard PU foam carbonizes above 120°C. Our steel-steel steam pipes use a composite system: high-density glass wool or inorganic hard insulation directly on the carrier pipe (withstands 350°C), followed by an aluminum foil reflective layer that blocks radiant heat, then PU foam for secondary insulation. This multi-layer steam pipe design achieves heat loss rates ≤10% versus traditional methods — 30–50% better than rock wool lagging alone.

◆ Steel Outer Jacket — Hermetically Sealed Against Groundwater. HDPE jackets soften above 80°C — steel-steel steam pipes need steel outer jackets. Our outer casing is factory-welded and pressure-tested for hermetic integrity. A professional anti-corrosion coating (3PE or high-strength epoxy) protects the steel steam pipe jacket from soil corrosion for decades. Unlike HDPE-jacketed pipes, steel-steel can be directly buried in high-groundwater environments without additional concrete protection.

◆ Internal Expansion Compensation — No Concrete Anchors. Steam pipes expand significantly when heated to 350°C. Our integrated expansion joints and sliding supports allow the inner carrier pipe to move freely within the outer steel jacket. This eliminates the need for massive concrete thrust blocks and anchor points, reducing civil works cost and installation time. The steam pipe system accommodates thermal cycling without structural fatigue.

◆ Direct Burial — No Expensive Concrete Encasement. Traditional steam pipelines require reinforced concrete ducts for protection. The steel-steel design's load-bearing outer jacket eliminates this requirement entirely. Direct burial saves 30–50% in civil construction costs and accelerates project timelines by weeks. The hermetic steel jacket keeps groundwater out permanently.

Steel-Steel Steam Pipe vs. Traditional Rock Wool Lagging

Feature	Sanjie Steel-Steel Steam Pipe	Traditional Rock Wool Lagging
Max Temperature	350°C continuous	250°C with risk of carbonization
Insulation	Multi-layer: glass wool + reflective + PU	Single-layer rock wool, no barrier
Heat Loss	≤10% (factory-tested)	20–50% (weather/degradation)
Outer Protection	Welded steel jacket + 3PE/epoxy	Aluminum/steel cladding, jointed
Waterproofing	Pressure-tested hermetic seal	Joint leakage over time
Thermal Expansion	Built-in sliding + expansion joints	External loops needed
Burial Method	Direct burial — no concrete duct	Requires concrete encasement
Service Life	30+ years	15–25 years (insulation degradation)
Installation Cost	30–50% lower (no concrete duct)	Higher civil works cost
Groundwater Safety	Rated for high water table	Insulation fails when wet

Technical Specifications

Parameter	Standard / Value
Inner Carrier Pipe	Seamless steel pipe (Q235B or equivalent)
Slip Layer	Allows free axial thermal displacement
Primary Insulation	High-density glass wool / inorganic hard insulation (350°C rated)
Reflective Layer	Aluminum foil barrier — blocks radiant heat transfer
Secondary Insulation	Rigid PU foam (for lower-temperature outer zone)
Outer Jacket	Spiral-welded steel casing (load-bearing)
Anti-Corrosion	3PE (3-layer polyethylene) or high-strength epoxy coating
Sliding Types	Inner sliding (lower cost) / Outer sliding (higher thermal efficiency)
Operating Temperature	Up to 350°C
Medium Pressure	≤2.5 MPa
Heat Loss Rate	≤10% (vs. traditional methods)
Service Life	30+ years
Standards	GB/T 29047 / ISO 9001
Certifications	ISO 9001 / ISO 14001 / CE
Fittings	Insulated elbows, tees, reducers, expansion joints, sliding supports
Packaging	Steel end caps + weather-resistant bundling

Application Scenarios

Urban Steam District Heating. Steel-steel steam pipes form the backbone of city steam networks for heating, industrial process supply, and domestic hot water. Direct burial without concrete ducts reduces street disruption and installation cost. Multi-layer insulation keeps delivered steam quality within spec over kilometers of buried steam pipe infrastructure.

1102(d1020f27b7).png

Power Plant & Enterprise Steam Supply. High-temperature steam pipe networks connecting cogeneration plants to industrial users. Up to 350°C and 2.5 MPa continuous operation. The outer sliding design's superior thermal efficiency (~22% better) minimizes condensation and energy loss in long-distance industrial steam pipe runs.

1103(e9bfff7410).png

Petroleum & Chemical Process Steam. Steel-steel steam pipes handle aggressive chemical plant environments where thermal cycling is frequent. Built-in expansion joints absorb repeated thermal displacement without fatigue. 3PE anti-corrosion coating resists chemical soil exposure where standard HDPE jackets would fail.

High-Groundwater & Harsh Soil Projects. The pressure-tested hermetic steel jacket is the safest option for steam pipes in wet environments. No moisture ingress means no insulation degradation. Unlike HDPE-jacketed pipes, steel-steel maintains full structural integrity when buried below the water table for decades.

Pipe Galleries & Complex Layouts. Outer sliding steam pipes with integrated sliding supports navigate pipe galleries and directional changes without external expansion loops. Thermal displacement is absorbed internally within the steam pipe system — no bulky above-ground compensators needed at direction changes.

Trusted Across 110+ Countries

Our steel-steel steam pipes serve district heating operators, power utilities, petrochemical plants, and EPC contractors worldwide. As drafters of 8 national standards, we engineer every steam pipe for your specific temperature, pressure, and thermal displacement requirements.

Service & Support

From sliding type selection (inner vs. outer) through expansion joint design to installation supervision, our team supports your entire steel-steel steam pipe project from engineering to commissioning.

Service Item	Details
Pre-Sales Consulting	Steam temperature/pressure analysis, inner vs. outer sliding selection, anti-corrosion coating recommendation.
Engineering Design	CAD/PDF with thermal displacement calculations, expansion joint positioning, sliding support layout.
Free Samples	At no charge. Customer covers freight. Cross-section for multi-layer insulation and jacket integrity verification.
Production & QC	Factory-welded steel jacket, pressure-tested hermetic seal. 100% QC for insulation thickness and coating adhesion.
Delivery	7–14 days. EXW, FOB, CIF. Container-optimized with full accessory kit.
MOQ	Flexible per project scope.
Technical Support	Installation supervision, expansion joint commissioning, sliding support alignment, anti-corrosion inspection.
After-Sales Warranty	30+ year comprehensive warranty. Dedicated team for steam pipe maintenance and technical support.
Payment Terms	T/T, L/C at sight. Flexible for long-term partners.
OEM / ODM	Custom steel grade, coating type, insulation combination, and specification available.