Product Description
As the core component for industrial equipment "joints", our bearing tubes leverage China's advanced metallurgy and precision processing, delivering high strength, accuracy, and stability for global clients.
Premium Material Foundation
Crafted from 20Cr, GCr15 and other high-quality alloy steels (specialized for bearings), they undergo strict composition testing (C, Si, Mn content compliance). Dual smelting (electric arc furnace + refining furnace) reduces inclusions, enhancing density to avoid cracks, ideal for high-speed and heavy-load conditions.
Micron-Level Precision
Through "hot rolling sizing → cold drawing → bright annealing", outer diameter tolerance is ±0.05mm, wall thickness tolerance ±0.1mm, and inner hole roughness Ra≤0.8μm. Laser diameter gauges and ultrasonic testing ensure no unevenness, ready for direct bearing ring processing (saves cost).
Versatile Specifications
- Regular: Outer diameter 25-180mm, wall thickness 3.5-20mm (black/bright surface).
- Custom: Outer diameter 5-426mm, wall thickness 0.4-100mm (fits butterfly valve bearing seats, precision parts).
Suitable for motors, machine tools, engine
Chemical Composition (%)
| Material |
C |
Si |
Mn |
S |
Cr |
Ni |
Cu |
Mo |
ASTM 52100
GBGCr15 |
0.95-1.05 |
0.15-0.35 |
0.25-0.45 |
0.025 |
1.3-1.65 |
0.3 |
0.3 |
0.4-0.55 |
ASTM 4118
GBGCr15SiMn |
0.95-1.05 |
0.4-0.65 |
0.9-1.2 |
0.025 |
1.3-1.65 |
0.3 |
0.3 |
0.15-0.25 |
ASTM A485-3
GBGCr15SiMoV |
0.95-1.05 |
0.4-0.65 |
0.4-0.7 |
0.035 |
3.8-4.4 |
0.3 |
0.3 |
0.15-0.25 |
ASTM T1
GB W18Cr4V |
0.7-0.8 |
0.17-0.37 |
0.4-0.7 |
0.035 |
0.8-1.1 |
0.3 |
0.3 |
0.3 |
ASTM 100CrMo7
GBGCr18Mo |
0.95-1.05 |
0.17-0.37 |
0.25-0.45 |
0.035 |
1.65-1.95 |
0.3 |
0.3 |
0.15-0.35 |
ASTM 8620H
GBG20CrNiMoA |
0.17-0.23 |
0.15-0.35 |
0.6-0.9 |
0.04 |
0.4-0.65 |
0.35 |
0.35 |
0.15-0.25 |
Mechanical property
| Material |
Diameter of sample
d
mm |
Heat treatment or condition. |
Tensile strength
σb
Mpa |
Point of yield
σs
Mpa |
Ratio of elongation
δ
% |
Reduction of section
ψ
% |
hardness
HBW |
Shock absorption energy
KV2
J |
ASTM 52100
GBGCr15 |
d=30 |
Quenching + tempering |
≥1600 |
≥1400 |
≥22 |
≥60 |
≤65 |
≥20 |
ASTM 4118
GBGCr15SiMn |
d=15 |
Quenching + tempering |
≥1800 |
≥1500 |
≥12 |
≥50 |
≤65 |
≥25 |
ASTM A485-3
GBGCr15SiMoV |
d=25 |
Quenching + tempering |
≥1800 |
≥1650 |
≥12 |
≥50 |
≤66 |
≥22 |
ASTM T1
GB W18Cr4V |
d=25 |
Quenching + tempering |
≥1450 |
≥1100 |
≥12 |
≥45 |
≤65 |
≥20 |
ASTM 8620H
GBG20CrNiMoA |
d=25 |
Quenching + tempering |
≥1100 |
≥850 |
≥12 |
≥45 |
≤63 |
≥40 |
Heat treatment process
Precision Heat Treatment
- Bright Annealing: After cold drawing, tubes go through protective atmosphere annealing (using nitrogen/hydrogen mixture) to eliminate internal stress, soften material (Hardness ≤ HB187) for easy processing, and keep surfaces bright (no oxidation).
- Quenching & Tempering: For high-wear scenarios, tubes undergo oil quenching (850-880ºC) + tempering (150-200ºC), forming fine martensite structure. This enhances surface hardness (HRC58-62) and wear resistance, while maintaining core toughness to avoid brittle fracture.
Auxiliary Quality Processes
- Pickling & Passivation: Before packaging, tubes are pickled with dilute acid to remove surface oxides, then passivated to form a protective film (anti-rust period up to 6 months) - critical for long-term storage and ocean shipping.
- Hydrostatic Testing: Random samples undergo 1.5x working pressure hydrostatic tests (30-50MPa) to check leak tightness, ensuring no hidden cracks in walls, suitable for high-pressure application scenarios.
All processes follow ISO standards, with real-time temperature/pressure monitoring (traceable records) to guarantee consistent quality across every batch.
Product specification
Specification: outer diameter of pipe is 25-180mm. The wall thickness is 3.5-20mm. Length can be customered.
1. International Universal Standards
- ISO 683-17 (ISO):The global authority for bearing steel. It specifies chemical compositions (e.g., GCr15: C 0.95%-1.05%, Cr 1.30%-1.65%), smelting methods (electric/converter furnace + secondary refining for purity), and mechanical properties (tensile strength ≥1080MPa, elongation ≥10%). Non-metallic inclusions (e.g., sulfides, oxides) must be ≤ Grade 2.0 to prevent cracking.
- ASTM A295 (ASTM):For high-carbon chromium bearing steel tubes. It focuses on dimensional tolerances (OD ±0.03mm, wall thickness ±0.05mm), surface quality (no cracks, scars), and non-destructive testing (ultrasonic testing for internal defects, sensitivity ≥Φ2.0mm flat-bottom hole), suitable for North American markets.
.
product application
1. Industrial Machinery
They make inner/outer bearing rings for motor spindles and CNC machine tools. Precision tubes (OD tolerance ±0.05mm, Ra ≤0.8μm) enable stable high-speed rotation (10,000+ rpm), reducing vibration and boosting machining accuracy. For chemical pumps, alloy tubes (e.g., 20CrMnTi) with HRC 58-62 hardness resist harsh fluids.
2. Automotive Sector
In EVs and traditional cars, they produce drivetrain, wheel hub, and engine auxiliary bearings. Cold-rolled tubes minimize friction (enhancing EV efficiency) and handle -40ºC~150ºC heat cycles via tight wall tolerance (±0.1mm).
3. Heavy Machinery
Thick-walled tubes (15-30mm) serve excavator boom joints and TBM parts. Quenched-tempered structures withstand 500kN loads and shocks, while passivated surfaces prevent rust in dusty environments.
Custom specs (OD 5-426mm, wall 0.4-100mm) meet diverse needs.
FAQ
Q1:who are we?
A:We are based in Shandong, China, start from 2022,sell to North America(60.00%),Western Europe(14.00%),South America(6.00%).There are total about 11-50 people in our office.
Q2:What is a seamless steel pipe?
A:Seamless steel pipes are perforated from whole round steel, and steel pipes without welds on the surface are called seamless steel pipes.,
Q3:What is the difference between ERW and seamless steel pipe?
A:Seamless pipe is manufactured by extruding the metal to the desired length; therefore ERW pipe have a welded joint in its cross-section, while seamless pipe does not have any joint in its cross-section through-out its length.,
Q4:What is seamless steel pipe used for?
A:Seamless steel pipe is regularly used in the transportation of fluids such as water, natural gas, waste and air.
Q5.what services can we provide?
A:Accepted Delivery Terms: FOB,CFR,CIF,EXW;
Accepted Payment Currency:USD,EUR,JPY,CAD,AUD,HKD,GBP,CNY,CHF;
Accepted Payment Type: T/T,L/C,D/P D/A,PayPal;
Language Spoken:English,Chinese
Q6.Can we get the some samples?Any charges?
A:Yes,you can get available samples in our stock.Free for real samples,but customers need to pay the freight cost.
Q7.How can we get your price ?
A:We need below information to quote for you:
1). Product Name
2). Standard
3). Material Grade (Chemical Composition)
4). Dimension
5). Quantity
6). The Drawing for Special Parts
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