310S / Inconel 600 Seamless Stainless Steel Thermocouple & RTD Protection Coil Tube
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. offers precision-engineered seamless stainless steel coil tubes specifically designed for use as thermocouple and resistance temperature detector (RTD) protection sleeves in demanding instrumentation environments. These coil tubes are engineered to address the critical engineering challenge of balancing rapid thermal response time with mechanical strength and corrosion resistance under extreme process conditions involving high temperatures and aggressive chemical media.
As a specialist in instrumentation-grade tubing, Jixing Metal Materials delivers coil tube solutions that ensure long-term sensor accuracy, extended service life, and reliable performance in continuous temperature monitoring applications across heavy industry sectors.
Material & Properties
The protection coil tubes are manufactured from premium-grade high-temperature alloys selected to withstand the most severe thermal and chemical environments encountered in industrial process instrumentation:
- 310S (UNS S31008) Seamless Stainless Steel: An austenitic chromium-nickel alloy offering exceptional resistance to oxidation and scaling up to 1150°C (2100°F). The low-carbon composition of 310S ensures superior resistance to intergranular corrosion and maintains structural integrity during prolonged exposure to elevated temperatures. Ideal for oxidizing and reducing atmospheres, molten salts, and high-temperature furnace applications.
- Inconel 600 (UNS N06600) Seamless Tube: A nickel-chromium-iron superalloy providing outstanding resistance to oxidation, carburization, and a wide range of corrosive media. Inconel 600 retains excellent mechanical strength at temperatures up to 1100°C (2012°F) and offers superior performance in environments containing sulfur compounds, molten zinc, and aggressive industrial gases.
Both grades are supplied in seamless construction to eliminate weld seams that could serve as initiation points for corrosion or thermal fatigue failure. The seamless microstructure ensures uniform metallurgical properties throughout the tube cross-section, critical for consistent thermal conductivity and predictable response characteristics.
Specifications
| Parameter | Specification |
|---|---|
| Material Grades | 310S (UNS S31008), Inconel 600 (UNS N06600) |
| Construction | Seamless coil tube |
| Outer Diameter Range | 3.0 mm – 12.7 mm (1/8" – 1/2") |
| Wall Thickness Range | 0.3 mm – 1.5 mm (optimized for response time vs. mechanical strength) |
| Maximum Operating Temperature | 1150°C (310S) / 1100°C (Inconel 600) |
| Coil Winding Diameter | Standard coil diameters available; custom winding configurations upon request |
| Surface Finish | Polished / Pickled & passivated; Ra ≤ 0.4 μm available |
| Tolerance (OD) | ±0.05 mm (tight tolerance available) |
| Tolerance (Wall Thickness) | ±0.02 mm (precision grades) |
| Application Classification | Instrumentation – Temperature Measurement (Thermocouple / RTD Protection Sleeve) |
Manufacturing Process
The production of these instrumentation-grade protection coil tubes follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical soundness, and consistent performance:
- Material Selection & Incoming Inspection: Certified seamless tube blanks are procured from approved mills with full traceability documentation, including mill test certificates and spectrographic analysis.
- Precision Cold Drawing: The seamless tube is cold-drawn through precision tooling to achieve the required outer diameter and wall thickness with tight tolerances, ensuring uniform cross-section geometry critical for consistent thermal response.
- Coil Winding: The drawn tube is wound into the specified coil configuration on precision mandrels to achieve the required coil diameter and pitch, suitable for thermocouple and RTD probe assembly.
- Surface Treatment: Tubes undergo pickling and passivation to remove scale and contaminants, establishing a protective chromium oxide passive layer. Additional mechanical or chemical polishing is available for applications requiring enhanced surface smoothness.
- Quality Control & Testing: Each batch undergoes dimensional verification, hydrostatic pressure testing, visual inspection, and material verification (PMI – Positive Material Identification) to confirm grade compliance and structural integrity.
Wall Thickness & Response Time Optimization
A defining engineering consideration in thermocouple and RTD protection sleeve design is the trade-off between thermal response speed and mechanical durability. Wenzhou Jixing Metal Materials provides expert guidance and custom wall thickness configurations to optimize this balance:
- Thin-wall configurations (0.3 mm – 0.6 mm): Deliver the fastest thermal response times, enabling rapid temperature tracking in dynamic process environments. Recommended for low-stress applications where response speed is paramount.
- Medium-wall configurations (0.6 mm – 1.0 mm): Offer a balanced combination of response speed and mechanical robustness, suitable for general-purpose high-temperature instrumentation.
- Thick-wall configurations (1.0 mm – 1.5 mm): Provide maximum mechanical protection against process fluid erosion, vibration, and mechanical impact. Recommended for high-flow or abrasive process environments.
Applications
These protection coil tubes are purpose-built for instrumentation applications requiring reliable temperature measurement under extreme conditions:
- Thermocouple Protection Sleeves: Encasing Type K, Type N, Type R, Type S, and Type B thermocouple elements in high-temperature furnace applications, heat treat furnaces, glass manufacturing, and ceramic kilns.
- RTD (Resistance Temperature Detector) Protection: Housing Pt100 and Pt1000 RTD sensing elements in process piping, reactors, and heat exchangers exposed to corrosive media.
- High-Temperature Process Monitoring: Steel mill continuous casting, petrochemical cracking furnaces, power generation boiler systems, and chemical reactor temperature control.
- Corrosive Environment Instrumentation: Acid processing, sulfuric acid production, chloride-containing environments, and molten metal temperature measurement.
- Multi-element Probe Assemblies: Coiled configurations suitable for multi-point temperature measurement probes and immersion-type thermometers.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems ensuring product reliability and regulatory compliance:
- ISO 9001:2015 Quality Management System Certified
- Material compliance with ASTM A269, ASTM A312, ASME SA-269, and EN 10216 standards
- Full traceability from raw material mill certificates through finished product delivery
- Hydrostatic pressure testing per ASTM A269 requirements
- Positive Material Identification (PMI) verification on all shipments
- Third-party inspection available upon customer request
Unique Selling Points
- Specialized Instrumentation Focus: Unlike general-purpose coil tube suppliers, Jixing Metal Materials specializes in temperature measurement instrumentation applications, providing domain-specific engineering expertise for thermocouple and RTD protection requirements.
- Dual Premium Alloy Availability: Offering both 310S and Inconel 600 seamless grades allows customers to select the optimal material for their specific temperature and corrosion environment.
- Wall Thickness Optimization: Expert capability to fine-tune wall thickness specifications, enabling precise balancing of thermal response speed against mechanical protection requirements.
- Seamless Construction: Elimination of weld seams ensures uniform material properties, superior corrosion resistance, and reliable performance under thermal cycling conditions.
- Custom Configuration: Flexible coil winding diameters, lengths, and dimensional specifications to meet application-specific instrumentation assembly requirements.
- Full Traceability & Certification: Complete material documentation and testing protocols ensuring compliance with international standards and customer quality requirements.
Technical Note: When selecting the appropriate protection coil tube for a specific thermocouple or RTD application, customers should specify the maximum process temperature, corrosive media composition, process fluid velocity, mechanical stress conditions, and required thermal response time (e.g., T63 or T90 response time). Wenzhou Jixing Metal Materials engineering team provides complimentary material selection and wall thickness optimization guidance to ensure optimal sensor performance and maximum service life.