Hydraulic pipe

for oilpneumaticcarbon steel

Overview
EAST AI’s 27SiMn Q+T Bored Tube is a high-strength seamless steel tube produced by quenching and tempering (Q+T) followed by precision boring. The Q+T treatment refines the microstructure and delivers uniform mechanical properties for reliable performance under high pressure and heavy loads. The inner bore is machined to tight dimensional tolerances and low surface roughness, making these tubes suitable for large-diameter hydraulic and heavy machinery cylinders.

Model / Brand / Material
Model: Bored Tube
Brand: EAST AI
Material: 27SiMn

Applications
Bored tubes are used across hydraulic and mechanical industries where high precision and load-bearing capacity are required. Typical applications include hydraulic cylinder barrels, pneumatic cylinders, construction and engineering machinery, mining equipment, agricultural machinery, lifting platforms, oilfield equipment, mechanical sleeves, precision structural components, and heavy-duty machine parts.

Technical Specifications
Material Grade: 27SiMn (GB/T 3077)
Condition: Quenched & Tempered (Q+T)
Outer Diameter: 80 mm – 800 mm
Wall Thickness: 10 mm – 100 mm
Length: up to 12 meters
Surface Finish: Hot rolled + bored (custom honed or SRB available)
Inner Diameter Tolerance: ±0.3 mm
Straightness: ≤ 0.5 mm/m
Surface Roughness (Ra): ≤ 3.2 μm (after boring); honing to Ra ≤ 0.4 μm available on request
Delivery Standard: GB / ASTM / DIN / EN

Main Features & Advantages

• High strength after heat treatment (Q+T) — 27SiMn in Q+T condition achieves tensile strength ~850–1000 MPa and yield strength >600 MPa, suitable for large hydraulic systems.
• Excellent impact & fatigue resistance — Good toughness and low-temperature impact performance for demanding environments such as mining and maritime applications.
• Precision boring process — Advanced boring equipment ensures high dimensional accuracy, smooth inner surface and concentricity; ready for honing or roller burnishing.
• Stable structure & high machinability — Q+T refines microstructure to improve dimensional stability and suitability for secondary machining (welding, threading, port cutting).
• Large-diameter capability — Available up to 800 mm OD to support large hydraulic cylinders.
• Custom processing options — Optional honing, skiving & roller burnishing (SRB), or chrome plating per requirements.

Manufacturing Process

• Raw material selection — High-quality 27SiMn seamless steel tube.
• Rough machining & cutting — Prepare tube blanks to required sizes.
• Quenching & tempering (Q+T) — Heat treatment to achieve required strength and toughness.
• Boring process — Precision boring to reach target ID and wall thickness.
• Straightening & finishing — Achieve optimal straightness and roundness.
• Inspection & testing — Check mechanical properties, dimensions, and internal defects.
• Surface protection — Apply anti-rust oil and end caps prior to packaging.

Quality Control

• Dimensional accuracy checks (ID, OD, wall thickness).
• Ultrasonic testing (UT) for internal defects.
• Mechanical tests (tensile, yield, impact).
• Hardness inspection (typical HB 260–290).
• Hydraulic pressure testing available on request.
• Certificates and test reports: ISO 9001:2015, GL AMM, MTC EN 10204 3.1; third-party inspection (SGS / BV / TÜV) available.

Characteristics / Technical Specifications

• Product name: 27SiMn Q+T Bored Tube
• Model: Bored Tube
• Brand: EAST AI
• Material grade: 27SiMn (GB/T 3077)
• Heat treatment: Quenched & Tempered (Q+T)
• Outer diameter range: 80–800 mm
• Wall thickness range: 10–100 mm
• Maximum length: up to 12 m
• Inner diameter tolerance: ±0.3 mm
• Straightness: ≤ 0.5 mm/m
• Surface roughness (Ra) after boring: ≤ 3.2 μm (ID); honing to Ra ≤ 0.4 μm available
• Tensile strength: ~850–1000 MPa; Yield strength: >600 MPa
• Typical hardness: HB 260–290
• Surface finish options: bored, honed, SRB (roller burnished), or chrome plated
• Standards: GB / ASTM / DIN / EN