AISI SAE 8617H Low-Alloy Case-Hardening Steel Precision Tubes for Bearings

1. Material Overview

AISI/SAE 8617H (UNS H86170) is a low-carbon nickel–chromium–molybdenum alloy case-hardening steel. It is designed to provide a very hard, wear-resistant surface layer after carburizing while maintaining a tough, fatigue-resistant core.

In this product, 8617H is supplied as seamless, cold-drawn precision tubes specifically optimized for bearing components such as outer and inner rings, sleeves, and bushings. The grade is recognized as a carburizing bearing-quality steel in international specifications and as a hardenability-controlled alloy, making it especially suitable for anti-friction bearing applications.

2. Specifications

Grade & designation

• Steel grade: AISI/SAE 8617H

• UNS number: H86170

• Type: Low-alloy Ni–Cr–Mo case-hardening steel, bearing quality

Product form

• Seamless mechanical tubing / precision tubes

• Manufacturing route: hot-pierced hollows, cold drawing or cold finishing, followed by heat treatment (normalized, stress-relieved, or quenched and tempered as agreed with the customer)

• Precision tube characteristics: tight dimensional tolerances and controlled maximum surface roughness in line with recognized precision tube standards

Dimensional range (typical, customizable)

• Outside diameter: up to approximately 380 mm for precision seamless tubes, depending on the specific standard and manufacturing route

• Wall thickness: from thin-wall sections for cages to heavier walls for bearing sleeves and rings

• Lengths: fixed or random; cut-to-length options available for bearing components

Delivery conditions

• +C (cold drawn/hard)

• +LC (cold drawn/soft)

• +SR (stress relieved)

• +A (annealed)

• +N (normalized)

• Q+T (quenched and tempered, including case-hardening cycles as required)

Typical supply options

• Straight tubes for machining into bearing rings and sleeves

• Near-net-shape tubes for bearing housings and precision bushings

• Material certificates to EN 10204 3.1 or 3.2 available on request

3. Key Features

1. Optimized for carburizing and case hardening

   • Carbon in the range of about 0.14–0.20% combined with nickel, chromium, and molybdenum provides excellent hardenability and stable case depth after carburizing.

   • The steel develops a high-hardness surface for wear and pitting resistance, with a tough core that can withstand impact and bending loads.

2. Tough, ductile core for bearing reliability

   • After appropriate quenching and tempering, 8617H achieves high tensile strength with good elongation and reduction of area, providing resistance to core cracking and bending fatigue.

3. Dimensional and surface precision

   • Cold-drawn precision tubes provide tight outside diameter, inside diameter, and wall-thickness tolerances and controlled surface roughness, reducing machining allowance and improving raceway consistency.

4. Bearing-quality cleanliness

   • When supplied as bearing-quality material, the steelmaking route focuses on low inclusions, controlled oxygen, and consistent microcleanliness, which are critical for rolling contact fatigue life.

5. Flexible heat treatment window

   • The Ni–Cr–Mo chemistry and specified hardenability support stable response to carburizing, carbonitriding, and quenched-and-tempered regimes, allowing customers to tailor case depth and core hardness to their bearing designs.

4. Our Advantages

4.1 “Can you guarantee consistent case depth and hardness for bearing races?”

We use 8617H as a carburizing bearing steel with controlled chemistry, cleanliness, and hardenability suited to bearing applications. Process routes and heat treatments are selected to give reliable carburizing or carbonitriding results, with case depth and surface hardness verified through standard hardness traverses and metallography. Core hardness and mechanical properties are validated on each heat or batch and documented in the mill test certificates.

4.2 “How do you control dimensional tolerance and surface quality of tubes?”

Our tubes are manufactured as precision cold-drawn products in accordance with recognized precision tube standards. This ensures tight tolerances on outside diameter and wall thickness, good straightness, and defined maximum surface roughness. Additional grinding or honing can be supplied when ultra-fine surface finishes are required before raceway grinding.

4.3 “Is the steel clean enough for high bearing life?”

We offer high-cleanliness melt routes such as electric-arc furnace with ladle refining and vacuum degassing, and, where required, electroslag remelting or vacuum induction plus remelting. These routes provide low inclusion content and low oxygen levels appropriate for bearing-quality steels. Inclusion ratings and cleanliness reports can be provided to support rolling-contact fatigue life requirements.

4.4 “Can you match international standards so my design and QA can be unified?”

The chemical composition of 8617H is aligned with widely used American specifications for carburizing alloy steels with defined hardenability bands. In addition, we can supply and cross-reference other case-hardening grades such as SAE 8620, 20MnCr5, SCM420H, and EN353 so that customers working under EN, JIS, GB, or GOST can adopt the closest matching grade. Precision tube dimensions and mechanical properties can be certified simultaneously to the relevant ASTM, EN, JIS, and GB standards as needed.

4.5 “What about logistics, MOQs, and traceability?”

We support flexible order quantities, from pilot lots for new bearing developments to high-volume production for automotive programs. Full heat-to-piece traceability is maintained, with bundles and tubes clearly marked as agreed. Documentation can include material certificates, non-destructive testing reports, dimensional inspection results, and heat-treatment records.

5. Chemical Composition

6. Mechanical Properties

7. Applicable Standards

ASTM / SAE

• Seamless mechanical tubing and alloy tubing standards for precision tubes

• Hardenability-controlled alloy bar standards for H-band steels such as 8617H

• Carburizing steels for anti-friction bearings

• General alloy steel bar and plate specifications

EN (Europe)

• EN standards for seamless cold-drawn precision tubes

• EN case-hardening steel standards covering grades such as 20MnCr5

JIS (Japan)

• JIS standards for alloy steel tubes for machine purposes

• JIS standards for structural steels with specified hardenability bands (SCM series)

GB (China)

• GB standards for cold-drawn and cold-rolled precision seamless steel tubes

• GB bearing-steel standards defining metallurgical quality requirements

GOST (Russia / CIS)

• GOST specifications for structural alloy steels, including case-hardening steels for gears, shafts, and bearing-related components

8. Application Fields

General application areas

• Rolling bearings and bearing components

• Power-transmission and gearbox parts

• Automotive and off-highway driveline components

• General mechanical engineering parts exposed to impact, bending, and cyclic loading

Specific uses in the bearing sector

• Bearing inner and outer rings machined from precision tubes and then carburized and ground

• Bearing sleeves and adapter sleeves where accurate wall thickness and roundness are important

• Bearing housings and bushings combining radial and axial load capacity with sliding or rolling contact

• Support bearings for gearboxes, axle assemblies, differential carriers, and similar power-transmission units

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.