316/316L/316Ti Stainless Steel 1/8-Inch Welded Capillary Tube for Flowline Control

316/316L/316Ti Stainless Steel 1/8-Inch Welded Capillary Tube for Flowline Control

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 Properties

316L and 316Ti stainless steels are commonly used for transporting corrosive media and in instrumentation control systems. 316L has a low carbon content, resulting in a lower risk of intergranular corrosion after welding; 316Ti, stabilized with titanium, exhibits more stable microstructural behavior under certain high-temperature conditions. For 1/8-inch welded capillary tubing, both materials are suitable for fluid control applications requiring dimensional accuracy, corrosion resistance, and continuous supply. MTSCO can match the appropriate material for you based on medium conditions, pressure requirements, and project standards, thereby reducing subsequent risks caused by material selection errors.

Manufacturing Process Flow

The core manufacturing process for these welded capillary tubes 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.

Quality Control System

·Raw Material Re-inspection: Raw materials are sourced from suppliers such as POSCO, TSINGSHAN, and Baosteel. 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.

Siri Laboratory

·Weld Radiographic Test Laboratory (RT)

·Chemical Composition Analysis Laboratory

·Intergranular Corrosion Test Laboratory

·Tensile Test Laboratory

·Hardness Test Laboratory

·Metallographic Laboratory

Equipped with professional instruments such as tensile testers, impact testers, metallographic microscopes, and hardness testers, the Siri Laboratory performs mechanical property and non-destructive testing, including tensile, flaring, flattening, bending, hardness, and radiographic testing. All test reports and samples are archived as required to facilitate order traceability, quality verification, and project acceptance.

FAQ

Q1: Which is more suitable for 1/8-inch flowline control: 316L or 316Ti?

A1: 316L is more widely used in standard corrosive media and welding applications. If the operating conditions involve higher temperatures or require stabilization properties, 316Ti should be considered. MTSCO can assist with material selection based on project conditions.

Q2: What is the maximum continuous length available for this welded capillary tube?

A2: Our control line products are available in long-length coils, up to 15,000 meters or 50,000 feet. Continuous lengths help reduce on-site splicing and improve installation efficiency. MTSCO’s in-house manufacturing facilities can accommodate long-length delivery requirements.

Q3: What are the main materials used for MTSCO coils?

A3: We offer a comprehensive range of stainless steel, duplex steel, and nickel alloy coils, including grades 304, 316L, 2205, 2507, Alloy 625, and Alloy 825. All raw materials are sourced from internationally renowned steel mills, and each batch undergoes PMI testing to ensure compliance with international standards such as ASTM and EN.