Product Overview

Our precision cold rolled seamless steel pipes are high-end precision tubular products manufactured through advanced multi-roller cold rolling technology, using premium hot-rolled seamless tubes as raw billets. Produced on precision rolling mills with strict process control, these pipes feature industry-leading dimensional accuracy, exceptional surface finish, uniform wall thickness and excellent concentricity. As an upgraded alternative to ordinary cold drawn pipes, they significantly reduce downstream machining processes, cut overall production costs, and are the preferred solution for high-precision industrial applications with strict tolerance requirements.

Manufacturing Process

1. Raw Material Screening: High-quality hot-rolled seamless tube billets are selected, with strict inspection on chemical composition, surface defects and dimensional deviation to ensure billet quality.

2. Pre-treatment: Billets go through pickling to remove oxide scale, followed by phosphating and saponification to form a uniform lubricating film, protecting the tube surface during cold rolling.

3. Precision Cold Rolling: The tube is processed through multi-roller high-precision cold rolling mills (e.g. LG series mills) in multiple passes. Outer diameter, inner diameter and wall thickness are precisely controlled to achieve extremely tight dimensional tolerances.

4. Heat Treatment: Stress relief annealing, normalizing or quenching & tempering is applied as required to eliminate cold working stress and optimize mechanical properties and metallographic structure.

5. Precision Straightening & Cutting: High-precision straighteners guarantee excellent straightness; dedicated saws perform precision cutting to deliver flat, burr-free end faces and strict length tolerance.

6. Finishing & Final Inspection: Optional surface treatments such as honing or polishing are available. All pipes undergo 100% dimensional inspection, non-destructive testing and cleanliness verification before delivery.

Key Features

· Ultra-tight dimensional accuracy: Far tighter tolerances on ID, OD and wall thickness than standard cold drawn pipes; inner diameter tolerance can reach H8/H9 grade, ensuring full interchangeability for precision assembly.

· Superior surface quality: Smooth, scale-free inner and outer surfaces with low roughness value, free from cracks, pits and other defects, directly suitable for sealing component fitting.

· Excellent wall uniformity & concentricity: Multi-roller rolling process ensures minimal circumferential wall thickness deviation and high coaxiality, ideal for high-precision hydraulic sealing and dynamic load conditions.

· Controllable mechanical properties: Cold work hardening improves tensile strength and surface hardness; customized heat treatment precisely adjusts strength, toughness and ductility to match application demands.

· High cleanliness standard: Inner wall cleaning and anti-rust treatment are available to meet the strict cleanliness requirements of hydraulic and pneumatic systems.

· Flexible customization: Support non-standard lengths, special tolerances, end processing (chamfering, threading, flaring) and anti-corrosion surface treatments for various niche scenarios.

Main Applications

· Hydraulic & pneumatic systems: High-precision hydraulic cylinder barrels, pneumatic cylinder tubes and servo system pipelines, serving as core supporting tubes for hydraulic equipment.

· Automotive & rail transit: Shock absorber cylinders, fuel injection pipes, steering system pipelines and precision brake system tubes.

· Precision machinery manufacturing: Die guide sleeves, textile machinery components, printing machinery rollers and precision structural parts for automation equipment.

· Aerospace & defense: Aircraft hydraulic pipelines, precision instrument connectors and special high-precision tubes for military equipment.

· Medical & instrumentation: Precision tubes for medical equipment, sensor housings and instrument signal pipelines.

· Petrochemical & new energy: Instrument pressure impulse tubing, small-diameter heat exchanger tubes and high-precision tubes for new energy equipment.

Standards & Specifications

Applicable Standards

· ASTM: A519, A106 Gr.B, A179

· DIN: DIN 2391 St37.4 / St44.4 / St52.4 (Precision Grade)

· EN: EN 10305-4, EN 10297-1

· GB: GB/T 3639 (Precision Class), GB/T 8162

Dimension Range

· Outer Diameter: 4 mm – 159 mm

· Wall Thickness: 0.8 mm – 16 mm

· Length: Custom cut-to-length from 0.5m to 12m with strict length tolerance

· Tolerance Grade: ID tolerance up to H8/H9; OD tolerance from ±0.02mm to ±0.1mm (subject to specific specifications)

Common Steel Grades

· Carbon steel: 10#, 20#, 45#, Q235B, Q355B, A106 Gr.B, St37.4, St52.4

· Low alloy steel: 16Mn, Q345B, 20Cr, 40Cr

· Alloy steel: 20CrMo, 42CrMo, 15CrMo, 12Cr1MoV

Quality Assurance

All precision cold rolled seamless pipes are manufactured under an ISO 9001 certified quality management system, with full traceability from raw material to finished products. Each batch undergoes 100% dimensional measurement, surface quality inspection, eddy current testing, hydrostatic pressure test and mechanical property verification. Cleanliness test reports are available for critical specifications.

Third-party inspection by SGS, BV, TÜV and other authoritative institutions is accepted. We provide stable supply and professional technical support for global precision machinery manufacturers, hydraulic system integrators and auto parts enterprises. For detailed quotations and sample requests, please contact our sales team directly.