316L EP Stainless Steel Coil Tube for Biopharmaceutical Chromatography and Ultrafiltration Systems

Product Overview

The 316L EP (Electropolished) Stainless Steel Coil Tube manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered process piping solution purpose-built for the biopharmaceutical industry. Designed specifically for chromatography and ultrafiltration system installations, this coil tube delivers exceptional chemical resistance across an extreme pH range of 2 to 12, making it the ideal choice for handling aggressive buffer solutions, cleaning-in-place (CIP) agents, and sanitizing-in-place (SIP) chemicals encountered in upstream and downstream bioprocessing workflows.

Unlike conventional tubing, this product is engineered with a low protein adsorption surface finish that minimizes biofilm formation and protein fouling, ensuring consistent process performance, reduced contamination risk, and extended cleaning intervals in highly sensitive pharmaceutical manufacturing environments.

Material & Properties

The coil tube is fabricated from ASTM A270 / AMS 5528 Grade 316L (UNS S31603) austenitic stainless steel, which provides superior corrosion resistance due to its enhanced molybdenum content (2.0–2.5%). The low carbon designation (≤0.03% C) eliminates intergranular corrosion risk during welding and heat treatment operations.

Key Material Characteristics

Specifications

Parameter Specification
Material Grade ASTM A270 / AMS 5528, 316L (UNS S31603)
Form Coil Tube (continuous coil configuration)
Outer Diameter Range 3.18 mm (1/8") to 50.80 mm (2")
Wall Thickness Range 0.50 mm (0.020") to 3.18 mm (0.125")
Inner Surface Finish Electropolished, Ra ≤ 0.4 μm (16 μin)
Outer Surface Finish Bright annealed or 2B finish
Coil Inner Diameter Standard: 450 mm (17.7"); Custom options available
Coil Length Up to 100 m (328 ft) per coil; custom lengths available
pH Compatibility 2 to 12 (buffer solutions, CIP/SIP chemicals)
Operating Temperature −40 °C to 450 °C (−40 °F to 842 °F)
Pressure Rating Up to 1.6 MPa (232 psi) continuous; higher on request
Welding Compatibility Orbital TIG (GTAW), laser welding; weld passivation available
Passivation Treatment ASTM A967 citric or nitric acid passivation
End Condition Plain, beveled, or pre-formed (custom per customer requirement)

Manufacturing Process

The production of this EP coil tube follows a rigorous multi-stage manufacturing process designed to meet the stringent quality requirements of the biopharmaceutical sector:

  1. Material Selection & Inspection: Premium 316L stainless steel strip is sourced from certified mills with full chemical composition verification (PMI testing) and mechanical property certification.
  2. Coil Forming: Precision roll-forming equipment shapes the flat strip into the desired tube geometry with tight dimensional tolerances (±0.05 mm), ensuring uniform wall thickness and consistent inner diameter.
  3. Welding: High-frequency resistance welding or orbital TIG welding creates a continuous longitudinal weld seam with minimal heat-affected zone.
  4. Electropolishing: The inner surface undergoes electrolytic polishing in a controlled chemical bath, achieving a Ra ≤ 0.4 μm surface roughness. This process simultaneously removes surface contaminants, eliminates micro-voids, and enhances the passive chromium oxide layer.
  5. Passivation: Post-electropolishing passivation treatment (ASTM A967) maximizes the protective chromium oxide film, ensuring optimal corrosion resistance for long-term service life.
  6. Coiling: The finished tube is wound into a controlled coil configuration with protective wrap and moisture barriers to prevent surface contamination during storage and transport.
  7. Final Inspection: Each coil undergoes dimensional verification, surface roughness measurement (profilometry), visual inspection, and optional eddy current testing for weld integrity.

Applications

Primary Applications in Biopharmaceutical Processing

Industry Segments

Quality Certifications

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system aligned with international standards to ensure consistent product quality and regulatory compliance:

Unique Selling Points

1. Extreme pH Range Compatibility (pH 2–12): Unlike standard 304L tubing, the 316L EP coil tube withstands the full spectrum of aggressive buffer solutions used in chromatography and ultrafiltration, eliminating material compatibility concerns across diverse process steps.

2. Low Protein Adsorption Surface: The electropolished inner surface (Ra ≤ 0.4 μm) significantly reduces protein adsorption and biofilm formation, directly contributing to higher product recovery rates, reduced carryover risk, and extended CIP/SIP cycle intervals.

3. Electrical Conductivity Compatibility: The uniform, smooth bore geometry ensures laminar flow characteristics and accurate conductivity measurements, which is critical for process analytical technology (PAT) compliance in modern bioprocessing.

4. Coil Configuration for Flexibility: The continuous coil format offers unmatched installation flexibility, minimizing the need for field fabrication and reducing contamination risk from additional welds during system assembly.

5. End-to-End Traceability: Full material traceability from mill certificate through final product, with lot-specific documentation supporting regulatory audits and quality investigations.

Ordering Information

Custom configurations are available upon request, including non-standard outer diameters, wall thicknesses, coil dimensions, and surface finish specifications. Technical consultation is provided to assist customers in selecting the optimal tubing specification for their specific bioprocessing application.

For detailed quotations, material certifications, and sample requests, contact Wenzhou Jixing Metal Materials Co., Ltd. directly.