Stainless Steel Coil Tube for Steam Reforming Furnace — High-Pressure Low-Temperature Heating Application

Product Overview

The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a specialized coiled tubular product engineered for use in steam reforming furnace heating systems, particularly in high-pressure steam low-temperature coil configurations. These coil tubes serve as critical heat-transfer elements within the radiant and convective zones of catalytic reforming furnaces, where they facilitate the efficient superheating of process steam while withstanding severe thermal cycling, mechanical fatigue, and corrosive environments. The product is designed to meet the rigorous demands of petrochemical and natural gas processing industries, where reliability and resistance to failure are paramount.

Based on extensive field experience and failure analysis studies — including investigations into burst tube incidents in steam reforming furnace high-pressure steam low-temperature coils — this product line incorporates enhanced metallurgical integrity, optimized wall thickness tolerances, and superior fatigue resistance to mitigate the primary failure modes observed in service, such as creep rupture, thermal stress cracking, oxidation scaling, and mechanical vibration-induced fatigue.

Material & Properties

Base Material Grades

Key Mechanical and Physical Properties

Specifications

Parameter Specification / Value Standard Reference
Outer Diameter (OD) 19.05 mm – 168.3 mm (customizable) ASTM A213 / ASME SA-213
Wall Thickness 1.5 mm – 12.7 mm (±10% tolerance) ASTM A213
Coil Inner Diameter (ID) 300 mm – 1500 mm (configurable per furnace design) Manufacturer specification
Maximum Operating Pressure Up to 4.5 MPa (high-pressure steam service) ASME BPV Code Section I
Design Temperature Range 400°C – 1100°C (low-temperature coil: 400–700°C) API 579 / NORSOK M-503
Surface Finish Mill finish / Polished / Passivated (Ra ≤ 0.8 μm available) ASTM A478
Tolerance on OD ±0.25 mm (for OD ≤ 50 mm); ±0.5 mm (for OD > 50 mm) ASTM A213
Tolerance on Wall Thickness ±10% of nominal ASTM A213
End Condition Plain end / Beveled end / Threaded end (per customer requirement) ASME B1.20.1
Heat Treatment Solution annealed and pickled (1050–1150°C, water quench) ASTM A213
Coil Length per Spool 30 m – 200 m (continuous coil) Manufacturer specification
Non-Destructive Testing Eddy current / Ultrasonic / Hydrostatic pressure test ASTM E165 / ASTM E114 / ASTM A213
Material Certification EN 10204 3.1 / 3.2 (mill test certificate) EN 10204

Manufacturing Process

1. Raw Material Selection and Incoming Inspection

High-purity stainless steel billets or strip stock are sourced from certified mills with traceable chemical composition documentation. Incoming materials undergo spectroscopic analysis (OES) to verify compliance with specified grade requirements, and visual inspection for surface defects. Only materials meeting or exceeding the specified carbon equivalent and sulfur/phosphorus limits are accepted for coil tube production.

2. Cold Rolling and Seamless Tube Forming

The coil tube manufacturing process begins with precision cold rolling of flat strip to achieve exact thickness tolerances. The strip is then fed into a cold-drawing or cold-rolling tube forming mill, where it is progressively formed into a seamless tubular shape through multiple reduction passes. This ensures uniform wall thickness and eliminates weld seams that could serve as failure initiation points under cyclic thermal loading.

3. Solution Annealing and Stress Relief

Following tube forming, the product undergoes a high-temperature solution annealing treatment at 1050–1150°C, followed by controlled cooling (water quench or air cool). This process dissolves carbides, homogenizes the microstructure, and relieves residual stresses introduced during forming. The annealed microstructure provides optimal grain boundary stability and resistance to sensitization.

4. Pickling and Passivation

The annealed tubes are subjected to acid pickling (using a mixture of nitric and hydrofluoric acid) to remove oxide scale and surface contamination. Subsequent passivation treatment forms a protective chromium oxide layer, enhancing long-term corrosion resistance in the steam and hydrocarbon environments encountered in reforming furnace service.

5. Coiling and Dimensional Verification

The finished tube is coiled to the specified inner diameter using precision coiling equipment that maintains consistent curvature without introducing additional plastic deformation. Each coil is inspected for dimensional accuracy (OD, wall thickness, coil ID) using calibrated measuring instruments. Non-destructive testing (NDT) is performed in accordance with ASTM standards.

6. Hydrostatic Pressure Testing

Every coil tube undergoes 100% hydrostatic pressure testing at a pressure typically 1.5× the maximum design pressure, with a hold time sufficient to confirm leak-tight integrity. Test results are documented in the material certification package.

7. Packaging and Dispatch

Coils are wrapped in protective paper or plastic film, secured with steel strapping, and packaged for transport. Each shipment is accompanied by a complete quality documentation package including mill test certificates, NDT reports, and dimensional inspection records.

Applications

Primary Application: Steam Reforming Furnace Heating Systems

The principal application of this coil tube is as a heating element in high-pressure steam superheaters within catalytic steam reforming furnaces. In this service, the coil tube transfers heat from the furnace radiant or convective zone to process steam, raising it to the required superheated temperature for downstream reforming reactions. The low-temperature coil section operates in the range of 400–700°C, where the tube must maintain structural integrity under sustained high pressure and cyclic thermal loading.

Secondary Applications

Failure Mitigation Features

Informed by documented burst tube failure analyses in steam reforming furnace high-pressure steam low-temperature coils, this product incorporates the following design enhancements:

Quality Certifications and Compliance

Standards Compliance

Certification and Testing Protocols

Traceability and Documentation

Each coil tube shipment includes a comprehensive quality dossier containing: heat number traceability to the original mill ingot, chemical analysis report (OES), mechanical test results (tensile, hardness), dimensional inspection records, NDT reports, hydrostatic test data, and final material certification. This ensures full supply chain traceability from raw material to finished product, enabling root-cause analysis in the event of field performance issues.

Unique Selling Points

Engineering-Informed Design: This coil tube product line is developed with direct reference to documented failure analyses of burst tubes in steam reforming furnace high-pressure steam low-temperature coils. The design addresses the specific failure mechanisms — including creep rupture, thermal fatigue cracking, oxidation scale spalling, and vibration-induced fatigue — identified in field investigations, resulting in a product with demonstrably improved service life and reliability.

Technical Support and After-Sales Service

Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including: application engineering consultation for coil tube selection and furnace integration; metallurgical analysis and failure investigation services for in-service tube performance; and ongoing material quality monitoring with periodic re-certification programs for long-term operational reliability. The company maintains a technical advisory team experienced in steam reforming furnace design and operation, capable of providing root-cause analysis and corrective action recommendations for tube performance issues encountered in the field.