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Shijiazhuang Faith Machinery Co.,Ltd’s tube mill machine offerings encompass everything from entry‐level mechanical mills for small‐batch production to fully automated lines capable of long, uninterrupted runs. Each tube mill machine is engineered to transform flat strip into finished tubes with weld seam quality, dimensional precision, and straightness tailored to diverse industry applications.
A typical tube mill machine is composed of several interconnected modules, carefully aligned to optimize strip flow and ensure process stability:
Payoff/Coil Carriage
Equipped with pneumatic or hydraulic expansion arms to grip the inner bore of the coil.
Automatic braking systems maintain consistent strip tension as the coil diameter decreases.
Coil car’s motorized traverse ensures the strip aligns correctly with the decoiler’s centerline.
Decoiler Stand
Mandrel decoilers use a box‐lock or wedge‐lock mechanism to secure coil inner diameters between 508 mm and 610 mm.
Expansion force is controlled to avoid strip distortion or metal folding.
Integrated tension arm, with load‐cell feedback, keeps strip taut as it feeds into the leveler.
Tension Leveling Unit
Comprises multiple crowned work rolls arranged in an alternating “S” pattern.
Each hydraulic cylinder adjusts roll force dynamically, flattening the strip and reducing yield point elongation.
Crown control algorithms ensure uniform flatness across widths up to 1,650 mm.
Forming Section
Sequence of forming stands, each containing upper and lower rolls mounted on bearings capable of supporting high lateral loads.
Rolls are machined from forged steel and can be chromium plated for wear resistance.
Stand housings feature shim‐based or motorized adjustment for rapid alignment during changeovers.
Welding Station
Flux delivery system applies granular flux to the seam area ahead of a submerged arc.
Single or dual‐wire heads deposit welding wire, creating a robust weld profile.
Flux recovery units collect unused flux, minimizing material waste.
Induction coil generates high‐frequency current to heat strip edges to a forging temperature (typically 1,200 °C–1,400 °C).
Two welding rolls press edges together, forging a seam with minimal flash.
Weld power supply uses insulated gate bipolar transistors (IGBTs) for precise current control and energy efficiency.
Tube mill machines may incorporate either ERW (Electric Resistance Welding) or SAW (Submerged Arc Welding) heads.
ERW Configuration:
SAW Configuration:
Scarfing and Bead Removal
For applications requiring a smooth internal tube surface (e.g., hydraulic lines), inline scarfing cutters remove residual weld flash.
Vacuum suction captures resulting metal shaving, preventing contamination of subsequent processes.
Sizing and Stretch Forming
Sizing stands with multiple calibration rolls refine tube outer diameter and circularity to within ±0.5% of nominal.
Stretch forming modules apply axial tension (5%–10% of yield strength) to correct tube ovality and improve straightness (typically achieving <2 mm straightness deviation over 6 meters).
Cutoff and End‐Forming
Flying cutoff saws, driven by servo motors, accurately shear tubes at programmed lengths up to 12 meters while running at line speed (up to 100 m/min for thinner gauges).
Hydraulic end-forming units perform operations such as chamfering, beveling, or cold expansion to prepare tube ends for downstream assembly or threading.
To ensure repeatable production quality, Shijiazhuang Faith’s tube mill machines incorporate comprehensive automation features:
Programmable Logic Controllers (PLCs): A distributed PLC network manages all drive axes, tension control loops, welding power supplies, and safety interlocks. Industrial‐grade communication protocols (EtherCAT or ProfiNet) link modules for deterministic performance.
Human‐Machine Interface (HMI): An intuitive touchscreen interface displays live process parameters—strip tension, welding current and voltage, tube dimensions—and allows operators to select from pre-loaded recipes. Recipes specify variables such as coil diameter, strip thickness, forming roll sequence, weld parameters, and cutoff length.
Closed-Loop Dimensional Control:
Laser micrometers located immediately downstream from the sizing stands measure tube outer diameter at multiple points around the circumference.
Ultrasonic wall-thickness gauges (optional) verify weld heat-affected zone consistency, especially important for thicker or high-strength materials.
The PLC adjusts roll positions and weld power settings automatically when measurements deviate from preset tolerances.
Weld Integrity Monitoring: Combination of surface cameras and ultrasonic flaw detectors continuously inspect each tube length. Detected anomalies—such as cracks, lack of fusion, or porosity—trigger automated tagging and rejection, keeping the main line running without manual intervention.
Tension and Speed Synchronization:
Decoiler, leveler, roll stands, and pull-through drives operate under coordinated VFD control. Speed ramps and synchronization algorithms prevent strip slack or tension spikes during coil transitions.
Encoder feedback from pull-through modules ensures that forming roll speeds match strip entry, minimizing forming errors and weld seam eccentricity.
Shijiazhuang Faith’s tube mill machines accommodate a broad array of materials and tube specifications:
Carbon Steel Tubing: Diameters from 15 mm to 168 mm, wall thicknesses from 0.8 mm to 6 mm. Applications include furniture frames, automotive components, and general structural tubing.
Stainless Steel Tubing: Diameters from 16 mm to 114 mm, wall gauges from 0.5 mm to 4 mm. Material grades supported include 304, 304L, 316, and duplex stainless steel for food, chemical, and architectural applications.
Alloy and High-Strength Tubing: Tube mill machines can be configured to process HSLA (High Strength Low Alloy) steel strips, dual-phase steels, and microalloyed grades, requiring precise weld power control and additional cooling to achieve targeted mechanical properties.
Aluminum and Galvanized Steel: For lighter-weight or corrosion-resistant tubing used in HVAC systems and outdoor structures, forming rolls and welding parameters are optimized to handle the unique thermal and springback characteristics of non-ferrous and coated materials.
Specialty Profiles: In addition to standard round tubing, simple square or rectangular profiles (e.g., 20 × 20 mm to 60 × 60 mm) can be produced by customizing forming rolls and adding seam trimming units.
Ensuring consistent tube quality and traceability is central to Shijiazhuang Faith Machinery Co.,Ltd’s philosophy:
Incoming Material Verification: Each coil’s mill test certificate (MTC) is logged at the decoiler. Operators input coil heat number, thickness, and material grade into the HMI, linking this data to the production batch.
Inline Non‐Destructive Testing (NDT):
Ultrasonic Testing (UT): Installed immediately after welding to detect internal flaws; a removable probe station allows for quick calibration and maintenance.
Eddy-Current Inspection (for stainless steel): Detects surface cracks or inclusions that may not be visible, especially important for highly polished or thin-walled tubes.
Dimensional Sampling: While continuous laser micrometer feedback provides 100% coverage of tube diameter, manual sampling with calipers and wall micrometers is performed at regular intervals to confirm the accuracy of automated measurements.
Automatic Marking and Identification: Tubes are marked via inkjet or laser etching with batch codes, size, and date. An optional bar‐code printer can generate labels for automated tracking through subsequent fabrication stages.
Data Archiving: All process parameters—from decoiler tension and leveling force to welding current profile and sizing roll positions—are archived in a centralized SQL database. Production managers generate traceability reports, support quality audits, and perform root cause analysis in the event of nonconformities.
Recognizing that each tube producer has distinct requirements, tube mill machines from Shijiazhuang Faith can be tailored extensively:
Modular Forming Stands: Customers can choose between fixed‐gap stands (for simple diameter ranges) or servo-driven stands (for rapid changeover between multiple sizes). Additional stands can be added to produce larger diameters or more complex profiles.
Welding Options:
Single‐Head vs. Dual‐Head ERW: Dual-head configurations allow two weld stations in series, increasing line speed by welding at two points—useful for high‐volume production of standard diameters.
SAW Integration: For thicker tubes (wall gauges above 6 mm), SAW modules can replace ERW heads, delivering deeper weld penetration and robust joint properties.
Cutoff Selection: Depending on production goals, customers may opt for flying cold saws (for continuous, high-speed operation) or focusing on hydraulically actuated cutoff shears (for lower speed, thicker wall tubes).
End-Forming Accessories: Inline cold expansion presses, chamfering units, or end-bellows forming tools can be added to streamline finishing operations for hydraulic, automotive, or appliance tubing.
Shijiazhuang Faith Machinery Co.,Ltd’s commitment to long-term customer success is reflected in its service offerings:
Turnkey Project Management: From the initial feasibility study to factory layout design and civil preparation, Faith Machinery’s engineers guide each customer step by step. Detailed 3D models ensure accurate equipment placement and utility routing—power, compressed air, cooling water—before shipment.
Installation and Commissioning: On-site mechanical alignment, electrical wiring, and PLC software commissioning are overseen by Faith Machinery’s technical team. Trial runs with customer-supplied strip verify machine performance and parameter settings.
Operator and Maintenance Training: Comprehensive training programs cover safe operation, HMI recipe management, preventive maintenance routines, roll profile inspections, and welding power maintenance. Detailed operation manuals and maintenance schedules support in-house teams.
Spare Parts and Consumables: A recommended spare parts kit—including form roll bearings, welding power supply capacitors, hydraulic seals, and shear blades—can be supplied alongside the machine or stocked locally. Priority shipping options minimize downtime in the event of unexpected breakdowns.
Remote Diagnostics and Software Updates: With secure remote access enabled, Faith Machinery’s support specialists can analyze alarm logs, review PLC configurations, and propose parameter optimizations without dispatching on-site technicians. Periodic software updates ensure compatibility with evolving control hardware and data security standards.
Upgrades and Retrofits: As production demands change, Faith Machinery offers retrofit solutions—such as adding extra forming stands, upgrading welding power supplies for higher efficiency, or integrating artificial intelligence–based weld inspection—to extend the service life and capabilities of existing tube mill machines.
By combining robust mechanical design, flexible configurations, and comprehensive service support, Shijiazhuang Faith Machinery Co.,Ltd’s tube mill machines empower manufacturers to produce high‐quality tubes—meeting industry standards, ensuring consistent throughput, and maximizing return on investment.
