UNS 31803 Duplex Steel Welded Coiled Tubing 1/2 inch ISO Certified

UNS31803 Duplex Steel Welded Coiled Tubing 1/2 inch ISO Certified

Specifications

Company and Factory Introduction

MTSCO provides stainless steel and nickel alloy product solutions for global industrial piping projects, serving industries such as oil and gas, chemicals, marine, and heat exchange equipment. For control line products, MTSCO established its own factory, Siri Tubing, in 2024, specializing in the production of welded coiled tubing, capillary tubing, control line tubing, and multi-core cables, all of which are ISO-certified. Leveraging our in-house manufacturing capabilities, MTSCO ensures more consistent quality control, reliable delivery coordination, and robust project support. We do more than just sell products—we are your trusted supply chain partner.

Material Composition

This product is made of 2205 duplex stainless steel (UNS S31803/S32205), whose microstructure consists of approximately 50% austenite and 50% ferrite. The yield strength of this material is approximately twice that of standard austenitic steels (such as 316L), allowing for thinner wall thicknesses under the same pressure and significantly reducing system weight. With a PREN value (Pitting Resistance Equivalent Number) greater than 34, it exhibits exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) in harsh environments containing chlorides and hydrogen sulfide. It is an ideal choice for high-pressure, corrosive applications such as offshore oil and gas chemical injection, deep-sea umbilical cables, and geothermal development.

Manufacturing Process Flow

The core manufacturing process for these welded coiled tubing typically includes strip welding, cold drawing, bright annealing, eddy current testing, and hydrostatic/air pressure testing, followed by precision coiling, marking, and final inspection as per project requirements. For small-diameter control line products, process stability directly impacts weld quality, dimensional consistency, and subsequent installation performance. MTSCO’s in-house facility, Siri Tubing, employs mature processes such as 100% laser welding, cold drawing, bright annealing, and plastic wrapping, making it suitable for the production of continuous-length control lines.

Hydraulic and Air Tight Test

To verify product reliability under extreme pressure, the production laboratory performs rigorous hydraulic test/air tight test on every coil of finished coiled tubing. Test engineers first seal both ends of the tubing and use a high-pressure pump system to inject water or high-purity nitrogen into the tubing, gradually increasing the internal pressure to multiples of the design standard. During the specified pressure stabilization period, high-precision sensors monitor the pressure curve in real time to confirm that the tubing exhibits no deformation or leakage when simulating deep-sea high-pressure or downhole conditions.

Quality Control System

·Raw Material Re-inspection: Raw materials are sourced from suppliers such as POSCO, TSINGSHAN, and JISCO. Each batch must be accompanied by an MTC and PMI. Upon arrival at the factory, materials undergo re-inspection to confirm that the material properties meet order specifications. MTSCO employs secondary verification to minimize the risk of material errors and mix-ups.

·Process Traceability: Every stage—from welding, cold drawing, and annealing to packaging—is supervised by the QC team, with records maintained through production process sheets and photographic documentation.

·Pre-shipment 100% Inspection: Prior to shipment, inspections are conducted for appearance, dimensions, quantity, PMI, airtightness, ET, and hydrostatic pressure tests. We also support third-party inspections by SGS, TÜV, and BV. MTSCO provides comprehensive quality assurance documentation for high-standard projects.

FAQ

Q1: What are the main materials used for MTSCO coiled tubing?

We offer a comprehensive range of stainless steel, duplex steel, and nickel alloy coiled tubing, including grades 304, 316, 2205, 2507, Alloy 625, and Alloy 825. All raw materials are sourced from internationally renowned steel mills, and each batch undergoes PMI material verification to ensure compliance with international standards such as ASTM and EN.

Q2: What is the maximum length of a single roll of this welded coiled tubing?

A2: Our welded coiled cable is available in rolls up to 50,000 feet (approximately 15 kilometers) in length, meeting the demands of long-distance downhole cabling, reducing the number of field splices, and enhancing system reliability. MTSCO’s manufacturing facilities are equipped for the production of extra-long continuous lengths.

Q3: What is the maximum operating pressure of the coiled tubing?

A3:Our welded coiled tubing undergoes standard hydraulic testing at 5,000 PSI and can withstand a maximum test pressure of 15,000 PSI, meeting the requirements of the vast majority of high-pressure applications.