Stainless Steel Annealed Coil Tube — Fully Soft Condition (O)
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. offers premium-grade stainless steel coil tube supplied in the fully annealed (soft) condition, designated as "O" per industry standards. This product line is engineered for maximum ductility and formability, making it the ideal choice for applications demanding complex bending, deep drawing, and expansion operations without the risk of cracking or work hardening. The coil tube is wound in continuous lengths on robust reels, enabling seamless feeding into automated processing lines and minimizing material waste.
Material & Mechanical Properties
The fully soft state is achieved through a controlled full annealing heat treatment, which relieves all residual stresses introduced during cold drawing and winding. This results in exceptional mechanical characteristics:
- Rockwell/Vickers Hardness: HV ≤ 180 — ensuring minimal resistance to plastic deformation
- Elongation at Break: ≥ 40% — providing outstanding ductility for severe forming operations
- Minimum Bending Radius: ≈ 3 × Outer Diameter — permitting tight-radius bends without wall thinning or fracture
- Expansion Ratio: ≥ 30% — supporting reliable tube end flaring and bellmouth forming
These properties collectively position the annealed coil tube as the benchmark material for fabrication processes requiring maximum formability while maintaining dimensional integrity.
Technical Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Mechanical Condition | Annealed — Fully Soft (O) | ASTM A213 / EN 10216 |
| Vickers Hardness (HV) | ≤ 180 | ASTM E92 |
| Elongation (%) | ≥ 40% | ASTM E8 |
| Minimum Bending Radius | ≈ 3 × OD | Internal Standard |
| Expansion Ratio | ≥ 30% | Internal Standard |
| Product Form | Continuous Coil / Reel | — |
| Supplier | Wenzhou Jixing Metal Materials Co., Ltd. | — |
Manufacturing Process
The production of fully annealed stainless steel coil tube follows a rigorous multi-stage process:
- Coil Drawing: Continuous drawing of seamless or welded stainless steel tube through precision dies to achieve target outer diameter and wall thickness tolerances.
- Pneumatic Winding: The drawn tube is wound onto heavy-duty reels under controlled tension to prevent kinking, ovality, or surface damage.
- Full Annealing Heat Treatment: The coiled tube is subjected to a solution annealing cycle at controlled temperatures followed by controlled cooling. This process recrystallizes the grain structure, eliminates work-hardening effects, and restores maximum ductility.
- Pickling & Passivation: Post-annealing surface cleaning removes oxide scale and establishes a uniform passive chromium oxide layer for corrosion resistance.
- Quality Inspection: Each coil undergoes dimensional verification, hardness testing, elongation measurement, and visual surface inspection prior to dispatch.
Applications
The exceptional formability of fully annealed stainless steel coil tube makes it indispensable across a wide range of industrial sectors:
- Automotive & Transportation: Fuel lines, brake lines, exhaust system components, and structural tubing requiring tight bends and complex geometries.
- Food & Beverage Processing: Sanitary piping systems, CIP (Clean-in-Place) loops, and hygienic transfer lines where smooth internal surfaces and corrosion resistance are critical.
- Medical & Pharmaceutical: Instrument tubing, dialysis equipment, and pharmaceutical fluid handling systems demanding biocompatibility and ease of sterilization.
- Oil & Gas: Subsea umbilical components, instrument tubing, and process piping requiring reliable forming performance.
- General Fabrication: Custom bent components, furniture frames, architectural features, and decorative applications where aesthetic surface finish and formability are paramount.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring that every coil tube product meets or exceeds international standards:
- ISO 9001 — Quality Management System certification for consistent production quality
- ISO 3834 — Welding quality assurance (applicable to welded tube variants)
- EN 10204 — Type 3.1 mill test certificates provided with each shipment
- Product Standards: Manufactured to ASTM A213, ASTM A269, EN 10216-5, and JIS G3459 specifications as applicable
Key Selling Point: With a minimum bending radius of only 3×OD and an expansion ratio exceeding 30%, this fully annealed coil tube delivers unparalleled formability — reducing secondary processing costs, minimizing scrap rates, and enabling design flexibility that other mechanical conditions cannot match.
All products are traceable to mill heat numbers, and customers may request additional testing including intergranular corrosion (ASTM A262), impact testing, or PMI (Positive Material Identification) verification upon request.