Hard-State (Fully Cold-Worked) Stainless Steel Coil Tube — High Pressure Resistance
Product Overview
The Hard-State (Fully Cold-Worked) Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered product designed for applications demanding exceptional mechanical strength and maximum pressure resistance. As a fully cold-worked (Hard, H) product, this coil tube undergoes extensive cold drawing and forming processes that significantly enhance its hardness, yield strength, and dimensional stability while maintaining adequate ductility for controlled forming operations.
This product is classified under the mechanical condition category of Hard (H) — Fully Cold Worked, making it the strongest state available in the coil tube product range. It delivers superior resistance to deformation under high-pressure conditions, making it ideal for specialized applications where structural integrity is paramount.
Material & Properties
The Hard-State coil tube is manufactured from high-grade austenitic stainless steel grades (such as 304, 304L, 316, and 316L), processed through full cold working to achieve maximum hardness and strength. The extensive cold work introduces significant work hardening, resulting in elevated tensile and yield strengths compared to annealed or semi-hard states.
- Vickers Hardness (HV): ≥ 280 — indicating a fully hardened, cold-worked microstructure with excellent wear and pressure resistance
- Elongation (A): ≥ 10% — sufficient ductility retained for limited forming operations such as bending
- Yield Strength: Significantly elevated due to full cold working, providing superior resistance to plastic deformation
- Corrosion Resistance: Maintains the inherent corrosion resistance of the base austenitic stainless steel grade
- Dimensional Stability: Excellent resistance to dimensional changes under load and thermal cycling
Important Note: Due to the fully cold-worked condition and limited elongation (≥10%), this product is restricted to pre-fabricated bends or straight sections only. It is not suitable for on-site forming, welding of complex geometries, or applications requiring significant post-installation shaping.
Specifications
| Parameter | Specification | Notes |
|---|---|---|
| Product Name | Coil Tube (盘管) | Delivered in coil form for efficient processing |
| Mechanical Condition | Hard (H) — Fully Cold Worked | Highest hardness state available |
| Vickers Hardness | ≥ 280 HV | Measured per ASTM E92 / ISO 6507 |
| Elongation (A) | ≥ 10% | Minimum ductility — limited forming capability |
| Pressure Resistance | Maximum | Highest pressure rating in the product range |
| Application Limitation | Pre-fabricated bends or straight sections only | Not for on-site forming or complex post-installation shaping |
| Material Grades | 304, 304L, 316, 316L (and equivalent) | Austenitic stainless steel |
| Product Category | Product Specifications — Mechanical Condition | Category: Hard State (H) |
| Item Number | 50 | Wenzhou Jixing Metal Materials Co., Ltd. catalog reference |
Manufacturing Process
The Hard-State coil tube is produced through a rigorous multi-stage cold working process that maximizes material strength while ensuring dimensional accuracy and surface quality:
- Raw Material Selection: High-purity austenitic stainless steel wire rod is sourced from certified mills and subjected to incoming material inspection for chemical composition and mechanical properties.
- Initial Drawing: The wire rod is drawn through a series of progressively reducing dies to achieve the target coil tube dimensions, introducing initial work hardening.
- Full Cold Working: Additional cold drawing passes are performed without intermediate annealing, progressively increasing dislocation density and grain deformation to achieve the target hardness of ≥ 280 HV.
- Coiling: The fully cold-worked tube is wound onto precision coils at controlled tension to prevent surface damage and maintain dimensional consistency.
- Quality Inspection: Each coil undergoes hardness testing, dimensional verification, and visual inspection to confirm compliance with specified mechanical properties.
The absence of intermediate annealing cycles is the defining characteristic of the fully cold-worked process, resulting in the maximum achievable hardness and strength within the coil tube product range.
Applications
The Hard-State (Fully Cold-Worked) coil tube is specifically engineered for applications requiring the highest pressure resistance and structural integrity:
- High-Pressure Hydraulic Systems: Pre-fabricated hydraulic lines and fluid conveyance systems operating under extreme pressure differentials
- Pressure Vessels & Piping: Straight sections and pre-formed bends for high-pressure process piping in chemical, petrochemical, and energy sectors
- Industrial Equipment: Structural components in heavy-duty machinery requiring maximum resistance to deformation
- Automotive & Aerospace: Precision components where weight reduction and maximum strength-to-weight ratio are critical
- Oil & Gas Industry: High-pressure wellhead connections and subsea piping systems (pre-fabricated configurations)
- Medical Equipment: High-pressure gas delivery systems in hospital infrastructure (straight sections and pre-bent assemblies)
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and adheres to internationally recognized standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 3834 — Welding quality management (for pre-fabricated assemblies)
- ASTM A213 / A269 — Compliance with seamless and welded stainless steel tube standards
- EN 10216 / EN 10217 — European standard compliance for stainless steel tubes
- GB/T — Chinese national standard compliance for stainless steel products
- Material Traceability: Full mill certificates (EN 10204 3.1) provided with each shipment
- Hardness Verification: Vickers hardness testing per ASTM E92 / ISO 6507 on every production lot
Unique Selling Points
- Maximum Pressure Resistance: With HV ≥ 280, this is the highest-hardness coil tube available in the product range, delivering unparalleled resistance to internal pressure and external loads
- Superior Dimensional Stability: The fully cold-worked microstructure provides exceptional resistance to creep and long-term deformation under sustained loads
- Enhanced Fatigue Life: Cold working significantly improves fatigue resistance, extending service life in cyclic loading applications
- Optimized Strength-to-Weight Ratio: Achieves maximum strength without increasing wall thickness, reducing overall system weight
- Specialized Application Focus: Purpose-built for high-pressure applications where pre-fabricated bends and straight sections are the standard configuration
- Full Traceability: Complete production documentation and material certification from raw material through final product
Application Advisory: Due to the limited elongation (≥10%), this product must be used exclusively as pre-fabricated bends or straight sections. Customers requiring on-site forming, complex bending operations, or post-installation shaping should consult Wenzhou Jixing Metal Materials Co., Ltd. regarding semi-hard (SH) or annealed (A) condition alternatives.