Stainless Steel Seamless Coil Tube — Hot Piercing & Cold Rolling Process
Product Overview
The Stainless Steel Seamless Coil Tube manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a premium-grade tubular product produced through the traditional seamless manufacturing route, combining Hot Piercing and Cold Rolling processes. This coil tube is designed for applications requiring high structural integrity, corrosion resistance, and dimensional precision across a wide range of wall thicknesses. The product is supplied in continuous coil form, offering significant material utilization advantages over straight-length seamless tubes.
As a seamless product, the coil tube contains no longitudinal weld seam, ensuring uniform metallurgical properties throughout the cross-section and superior performance under pressure, temperature, and chemical exposure conditions.
Material & Properties
- Material Grades: 304, 304L, 316, 316L, 321, 310S, 316Ti, 904L, and other austenitic/stainless steel grades conforming to ASTM, AISI, EN, and JIS standards.
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and intergranular corrosion due to the high chromium and nickel content inherent in austenitic stainless steels.
- Mechanical Properties: High tensile strength, elongation, and hardness achieved through the cold rolling reduction process, providing superior formability and fatigue resistance.
- Surface Finish: Available in BA (Bright Annealed), 2B, No.4, and custom finishes depending on application requirements.
- Non-magnetic: Inherent non-magnetic characteristics of austenitic grades make this product suitable for sensitive industrial environments.
Specifications
| Parameter | Specification |
|---|---|
| Product Type | Seamless Coil Tube (盘管) |
| Manufacturing Process | Hot Piercing + Cold Rolling |
| Outer Diameter (OD) | 6 mm – 219 mm (custom sizes available) |
| Wall Thickness | 0.5 mm – 12 mm (wide range supported) |
| Single Length (Pre-Coil) | ≤ 30 m (maximum per straight section) |
| Coil Form | Achieved via welding/splicing of straight lengths |
| Coil Weight | Up to 5,000 kg per coil (typical) |
| Applicable Standards | ASTM A213, ASTM A269, ASTM A312, EN 10216-5, GB/T 14976 |
| Surface Treatment | BA, 2B, Pickled, Custom |
| Packaging | Export-standard wooden crate or steel frame coil packaging |
Manufacturing Process
The production of this seamless coil tube follows the traditional and well-established Hot Piercing and Cold Rolling route, which is widely recognized in the stainless steel tube industry for its ability to produce tubes with a broad wall thickness range and consistent quality.
- Raw Material Preparation: High-quality stainless steel billets (solid bars) are sourced and inspected for chemical composition and mechanical properties prior to processing.
- Hot Piercing: The heated billet is pierced through a mandrel system at elevated temperatures (typically 1100–1200°C) to form a hollow shell. This step establishes the initial inner diameter and outer diameter geometry.
- Hot Rolling: The pierced shell is further elongated and reduced in wall thickness through hot rolling mills, achieving the approximate target dimensions.
- Pickling & Annealing: The hot-rolled tube is subjected to acid pickling to remove scale and oxidation, followed by solution annealing to restore ductility and achieve the desired microstructure.
- Cold Rolling: The tube undergoes cold reduction to achieve final dimensions with tight tolerances. This process enhances surface finish, dimensional accuracy, and mechanical strength through work hardening.
- Final Annealing & Pickling: A final annealing and pickling cycle ensures optimal surface quality and stress relief.
- Dimensional Inspection: Each tube is inspected for outer diameter, wall thickness, straightness, and surface defects.
- Welding & Splicing: Straight lengths (each ≤ 30 m) are butt-welded or fusion-welded together to form a continuous coil. The weld joints are inspected to ensure structural integrity and leak tightness.
- Coiling: The continuous tube is wound into a compact coil for efficient storage, transportation, and downstream processing.
Unique Selling Points
- Wide Wall Thickness Range: The Hot Piercing + Cold Rolling combination enables production of tubes from ultra-thin wall (0.5 mm) to heavy-wall (12 mm) configurations, offering unparalleled flexibility.
- True Seamless Construction: Absence of longitudinal weld seam ensures uniform strength, superior pressure containment, and resistance to stress corrosion cracking.
- Continuous Coil Supply: Enables downstream users to minimize cutting losses, reduce fabrication time, and achieve higher material utilization rates compared to straight-length supply.
- Traditional Process Reliability: The hot piercing and cold rolling route is a mature, well-documented manufacturing method with decades of proven performance data across global industries.
- Customizable Specifications: Wenzhou Jixing Metal Materials Co., Ltd. offers tailored dimensions, grades, and surface finishes to meet specific customer requirements.
Applications
- Chemical & Petrochemical Industry: Heat exchangers, reactors, piping systems, and process vessels requiring corrosion-resistant seamless tubing.
- Food & Pharmaceutical Processing: Hygienic piping, CIP (Clean-in-Place) systems, and food-grade transfer lines.
- Automotive Industry: Exhaust systems, fuel lines, and structural components.
- Energy Sector: Solar thermal collectors, heat exchanger tubes, and power plant components.
- Oil & Gas: Subsea pipelines, wellhead equipment, and offshore platform structures.
- Medical Equipment: Surgical instrument shafts, endoscope tubing, and medical device components.
- Aerospace: Hydraulic lines, fuel systems, and structural tubing where weight and reliability are critical.
Quality Certifications & Standards
- Manufactured in accordance with ISO 9001:2015 Quality Management System requirements.
- Product compliance with ASTM A213 (Seamless and Welded Austenitic Stainless Steel Tubing for High-Temperature Service), ASTM A312 (Seamless and Welded Austenitic Stainless Steel Tubes, Pipes, and Fittings), and EN 10216-5 (Technical Delivery Conditions for Non-Alloy and Alloy Steel Tubes for Pressure Purposes).
- Available Mill Test Certificates (MTC) including chemical analysis, mechanical testing, hydrostatic testing, and dimensional inspection reports.
- Third-party inspection available upon request (e.g., SGS, BV, TUV).
- Hydrostatic pressure testing performed on 100% of product to ensure leak tightness and structural integrity.
- Traceability maintained throughout the manufacturing process from raw material to finished coil.
Note: Each coil tube is produced from straight lengths of maximum 30 meters, joined through precision welding to form a continuous coil. Customers requiring weld-free continuous lengths should consult Wenzhou Jixing Metal Materials Co., Ltd. for alternative supply options. All product specifications are subject to confirmation based on order quantity, grade selection, and specific application requirements.