Bearing Tube: Small-Diameter Cold-Rolled Precision Seamless Tube for Mechanical Components

Material Overview

This product is a small-diameter, cold-rolled (or cold-drawn) precision seamless steel tube designed for high-demand mechanical parts—especially where fatigue resistance, wear resistance, dimensional stability, and consistent microstructure are critical.

It is typically produced in two material families:

• Through-hardening bearing steels (100Cr6, 100CrMn6): high-carbon chromium steels engineered for rolling-contact fatigue life, with controlled microstructure and cleanliness expectations for bearing applications.

• Case-hardening steels (16MnCr5, 20MnCr5): carburizing grades used when you need a hard wear-resistant case + tough core, common in gears, shafts, and transmission components.

• 100CrMo5 is commonly referenced as DIN/W-Nr. 1.2303 (high-carbon Cr-Mo alloy steel). If your project requires an ISO bearing-steel certificate, confirm the intended grade family during purchasing (bearing-steel vs. tool/alloy steel designation).

Specifications

Typical procurement specifications for precision bearing/mechanical tubes include:

• Dimensions: OD / ID / wall thickness (as per drawing)

• Length & end finish: fixed/random length, deburred/chamfered ends

• Dimensional accuracy: OD/ID tolerance class, ovality, straightness

• Surface condition: cold-rolled/cold-drawn surface, pickled/phosphated/oiled

• Delivery (heat treatment) condition: e.g., +A / +AC / +TH / +FP (as required by machining or final heat treatment route)

• Inspection & documentation: EN 10204 3.1 certificate, traceability to heat/cast, agreed NDT (UT/ET), decarburization and surface quality control

Key Features

• Seamless structure for reliable strength and uniformity in machining and heat treatment.

• Controlled microstructure (e.g., spheroidized carbides for through-hardening bearing steels when ordered in annealed conditions).

• High cleanliness focus (bearing steels emphasize low non-metallic inclusions and defined surface quality expectations).

• Precision tube expectations: tight dimensional tolerances and defined surface requirements can be specified for precision-tube supply.

Our Advantages

1) “How do you control decarburization and surface imperfections that reduce fatigue life?”
We align production and inspection to the same concerns written into bearing-steel requirements: decarburization and surface imperfections must be limited/controlled, and surface quality is treated as a key acceptance item. We can provide agreed controls (metallographic checks, machining allowance strategy, surface inspection/NDT) to match your drawing and service conditions.

2) “Can you provide full traceability and an EN 10204 3.1 inspection certificate?”
Yes—traceability (heat/cast linkage) and 3.1 inspection documentation can be supplied to support professional procurement, PPAP-style records, and audit requirements. EN 10204 defines the 3.1 certificate as a manufacturer declaration with test results.

3) “Will the tube meet precision tolerances and surface requirements for efficient machining/honing?”
Precision tube supply is built around clearly defined dimensional tolerances and specified surface expectations—reducing machining time, improving yield, and supporting stable assembly fits (especially critical for small diameters). We recommend confirming the target tolerance class, straightness, and roughness in the RFQ.

Chemical Composition

Mechanical Properties 

Standards & Grade References (ASTM / EN / GOST / JIS / GB)

• EN (Europe)

  • EN ISO 683-17: bearing steels such as 100Cr6 and 100CrMnSi6-4 (100CrMn6).

  • EN 10084: case-hardening steels such as 16MnCr5 and 20MnCr5.

• ASTM (USA)

  • ASTM A295/A295M: high-carbon anti-friction bearing steel (commonly associated with 52100-type bearing steel requirements, including decarburization/surface limits).

  • ASTM equivalence is often referenced as: 100CrMnSi6-4 ↔ ASTM A485 in manufacturer cross-reference tables.

• GOST (Russia/CIS)

  • GOST 801-1978: bearing steel family (e.g., ШХ15 / ShKh15).

  • Case-hardening approximate equivalents are often listed as 15HG / 18KHG depending on grade mapping.

• JIS (Japan)

  • JIS G4805: high carbon chromium bearing steels for rolling bearings.

  • JIS G4053: machine structural low-alloy chromium steels (commonly referenced for carburizing families such as SCr415/SCr420).

• GB (China)

  • GB/T 18254-2016: High-carbon chromium bearing steel (bearing-steel family reference).

  • Approximate GB equivalents for carburizing grades are often referenced in cross-grade tables (e.g., 15CrMn / 20CrMnTi depending on mapping).

Application Areas

• Rolling bearings & motion systems: bearing rings, sleeves, rollers/needle components, precision spacers.

• Automotive & industrial transmissions: carburized gears, gear shafts, splined sleeves, cam components (16MnCr5/20MnCr5).

• General mechanical engineering: high-wear bushings, precision shafts, pump parts, spindles—where dimensional stability and surface quality drive performance.

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.