AISI 8620 hot-rolled round bar is an economical, versatile case-hardening alloy that delivers a wear-resistant surface and a tough ductile core after carburizing and heat treatment; it’s ideal for shafts, gears, bushings and components requiring high surface hardness with minimal distortion. For buyers seeking factory pricing and fast lead times, MWAlloys supplies certified 8620 hot-rolled bars from Chinese mills at competitive ex-works/FOB rates and short-stock delivery for standard diameters.
What is AISI 8620 alloy steel?
AISI 8620 is a low-carbon, case-hardening nickel-chromium-molybdenum steel designed to produce a hard, wear-resistant surface layer with a tough, ductile core after carburizing and appropriate heat treatment. It is widely used where a combination of surface hardness, fatigue resistance and core toughness is required for parts that may be worn but must retain impact resistance at the center. Typical supply conditions include hot-rolled bar, cold-finished bar and forged blanks.
Also read: AISI 8630 Alloy Steel Bar
Chemical composition
Below is a compact table giving the commonly referenced chemical ranges for AISI/SAE 8620. Individual mill certificates or purchase orders should specify exact limits.
| Element | Typical range (weight %) |
|---|---|
| C (Carbon) | 0.18 – 0.23 |
| Mn (Manganese) | 0.60 – 0.90 |
| Si (Silicon) | 0.15 – 0.35 |
| Cr (Chromium) | 0.40 – 0.80 |
| Ni (Nickel) | 0.40 – 0.70 |
| Mo (Molybdenum) | 0.15 – 0.25 |
| P (Phosphorus) | ≤ 0.035 (max) |
| S (Sulfur) | ≤ 0.040 (max) |
Notes:These ranges reflect typical mill chemistry; order limits should refer to the specific standard or supplier certificate.
Key material properties
The properties below are for commonly supplied conditions of 8620 (annealed or normalized/hot-rolled) and will change significantly after carburizing and quench/tempering.
| Property | Typical value / range |
|---|---|
| Density | ≈ 7.85 g/cm³ (7,850 kg/m³) |
| Tensile strength (UTS) | ~ 500 – 650 MPa (varies with heat treatment) |
| Yield strength (0.2% offset) | ~ 350 – 450 MPa |
| Elongation (A%) | 15 – 30% (depending on condition) |
| Hardness (annealed) | HBW ≈ 140 – 200 |
| Elastic modulus (E) | 190 – 210 GPa |
| Typical carburized case hardness | up to HRC 58–62 (surface after proper case hardening) |
| Toughness | Good core toughness; favorable impact energy after correct treatment |
Reference datasheets and manufacturer test certificates provide tighter property windows for specific lots. Major material databases and supplier datasheets report similar ranges and test data.
Heat treatment, carburizing and recommended processes
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Carburizing (gas, liquid or pack) is the usual route: add carbon at elevated temperature to form a high-carbon case followed by quenching to produce a hard wear surface while retaining a ductile core. Typical case depth: 0.5–2.5 mm (can be specified up to several millimeters depending on process).
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Quench & temper of the case produces surface hardness (HRC 55–62 possible), tempering of the core yields desired toughness (core hardness often kept between HRC 30–40 depending on the application).
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Normalizing / annealing options for mill and shop: mill anneal for good machinability; spheroidize anneal when heavy machining is required.
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Distortion control: 8620 is chosen when low distortion during hardening is important; proper fixturing and tempering cycles reduce residual stress and distortion.
Practical note for fabricators: specify the target case depth/profile, quench medium (oil, polymer, salt, or pressurized gas), and post-quench tempering schedule in the purchase order to ensure repeatable results.
Hot-rolled round bar specifications
Common commercial specifications apply to 8620 in bar form: ASTM A29 (general requirements for hot-wrought bars), ASTM A322 (hot-rolled alloy steel bars—standard grades) and ASTM A108 for cold-finished bars when applicable. Typical supply forms: hot-rolled black bar, peeled/turned, ground/turned, or quenched & tempered in some cases.
Typical hot-rolled round bar size ranges (commercial):
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Small rounds (hot rolled): 6 – 100 mm diameter
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Large sections (forged/rolled): up to 300–1000 mm (specialty mills)
Typical mechanical spec for hot-rolled 8620 (examples):
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Tensile: ~ 80–100 ksi (550–690 MPa) (depends on condition and finish)
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Yield: ~ 40–65 ksi (275–450 MPa)
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Brinell hardness (as supplied): 140–200 HB
What is AISI 8620 equivalent to?
Common international equivalents (approximate chemistry / use):
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EN / DIN: 20NiCrMo2-2, 20MnCr5 sometimes used as functional equivalents for case-hardening steels.
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JIS / Japanese: SNCM220 (reference in JIS catalogues).
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Other notations: 1.6523 (some EU references).
These equivalents are functional matches and manufacturers often list multiple designations for the same mill product — always confirm composition and mechanicals for interchangeability.
What is AISI 8620 Round Bar used for?
Common components and sectors:
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Gears, gear shafts and pinions (carburized case for wear resistance)
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Transmission shafts, axles and splines (requires tough core)
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Bushings, pins, sleeves and bearing components (surface wear resistance)
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Automotive parts (powertrain components), agricultural equipment, heavy machinery, drive components and industrial valves
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Small to medium forgings where carburized surface is required
Reason: the alloying elements (Ni, Cr, Mo) promote case hardening performance while keeping low carbon for core toughness.
8620 steel vs 4140
| Aspect | AISI 8620 | AISI 4140 |
|---|---|---|
| Primary design purpose | Case-hardening (carburizing) to give hard case + tough core | Quenched & tempered structural/hardenable steel; through-hardening |
| Carbon (nominal) | ~0.18–0.23% (low) | ~0.38–0.43% (medium) |
| Typical use | Shafts, carburized gears | High-strength shafts, tooling, heavy pins |
| Hardenability / heat treatment | Good for carburizing; core remains ductile | Higher hardenability; can be through-hardened to much higher core hardness |
| Typical core toughness post-treatment | High (designed for tough cores) | Good but can be brittle if over-hardened without tempering |
If you need a hard skin and a ductile core, 8620 is the usual choice. If you need high uniform strength/hardness through the section, choose 4140. Comparative datasheets and conversion tools show these differences in mechanical targets and chemistry.
Sizes and weights — standard sizes and how to calculate mass
Mass formula (metric):
Weight (kg per metre) = (π/4) × (diameter in metres)² × density (7,850 kg/m³)
Mass formula (imperial) — convert afterwards: 1 kg = 2.20462262 lb, 1 m = 3.2808399 ft.
Below are calculated, accurate weights for commonly stocked diameters (kg/m and lb/ft). (Calculation used standard steel density 7.85 g/cm³.)
| Diameter (mm) | Diameter (inch) | Weight (kg/m) | Weight (lb/ft) |
|---|---|---|---|
| 10 | 0.393 | 0.617 kg/m | 0.414 lb/ft |
| 20 | 0.787 | 2.466 kg/m | 1.657 lb/ft |
| 25 | 0.984 | 3.853 kg/m | 2.589 lb/ft |
| 30 | 1.181 | 5.549 kg/m | 3.729 lb/ft |
| 40 | 1.575 | 9.865 kg/m | 6.629 lb/ft |
| 50 | 1.969 | 15.413 kg/m | 10.357 lb/ft |
| 75 | 2.953 | 34.680 kg/m | 23.304 lb/ft |
| 100 | 3.937 | 61.654 kg/m | 41.429 lb/ft |
| 150 | 5.906 | 138.721 kg/m | 93.216 lb/ft |
| 200 | 7.874 | 246.615 kg/m | 165.718 lb/ft |
(If you need a custom size, request a weight schedule from the supplier or use the formula above to compute exact mass.)
Tooling note: stock inventory is frequently quoted in tons (metric) or linear metres — convert using the table above for order planning.
Price comparison United States, Europe, China (2025)
Important: steel and bar prices move with global commodity cycles, tariffs, logistics and mill schedules. The ranges below reflect market-available supplier quotes and distributor listings in 2025; use them to estimate budgets but request firm quotes for order placement.
| Region | Typical 8620 hot-rolled round bar price (representative 2025 range) | Notes / source |
|---|---|---|
| United States (distributor/retail) | Retail examples: US$ 200–$350 per 1 ft piece (varies by diameter/length). For bulk, estimated $900–$1,400 / metric ton for alloy long products (order sizes and finishes affect cost). | Retail catalog prices for specific cut lengths shown at distributors (example retail listings). |
| Europe (wholesale/ mill ex-works) | Bulk/wholesale typical long-product alloy price indices in mid-2025: ≈ US$ 600–$750 / metric ton (region & product form dependent); premium for small OD bars and value-added processing. | European long product indices and market commentary (monthly assessments). |
| China (mill / FOB / factory) | Factory/FOB offers commonly seen: US$ 700–$1,200 / metric ton for hot-rolled 8620 depending on MOQ, finish and mill brand; some small suppliers list lower per-ton quotes for large orders on trading platforms. | China supplier listings and B2B platforms show broad ranges; factory price advantage is typical for large lot buys. |
How to interpret these ranges:
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Distributor retail prices (small quantities, cut & ship) are always higher than mill FOB/EXW. Example: a single 4.25" (≈108 mm) x 12" bar on a US retail site showed a per-foot price consistent with the table above.
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European ex-works prices are often quoted per tonne for long products; specialty case-hardening alloys can carry a small premium over basic carbon long products.
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China factory quotes from verified mills/traders typically show the best per-ton pricing for bulk orders (5–20+ tons MOQs), but shipping, duties and inspection add to landed cost.
Buyer recommendation: request formal quotations (including MTC/mill test certificates, surface finish, length tolerance, heat treatment if requested, packing and delivery terms). For long-term procurement, negotiate a rolling contract with agreed inspection points and clear acceptance criteria.
Inspection, testing and standards to specify
To ensure consistent quality, include these items in the purchase order / material specification:
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Mill Test Certificate (MTC / EN 10204 type 3.1 or 2.2) showing chemical analysis and mechanical test results.
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Dimensional tolerances referenced to ASTM A29 / ASTM A108 as appropriate.
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Non-destructive testing (NDT): ultrasonic or magnetic particle inspection for critical forged parts (specify if needed).
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Hardness profile report after carburizing (specify case depth and surface/core hardness targets).
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Traceability & heat number stamping: essential for quality systems and warranty.
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Supplementary requirements (e.g., surface finish: peeled/turned/ground; internal soundness tests).
Procurement tips + MWAlloys capability statement
If your project needs reliable, cost-effective 8620 hot-rolled round bars, MWAlloys provides turnkey supply from China that includes:
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Factory pricing: 100% factory-direct EXW/FOB pricing for standard diameters — competitive for bulk purchases.
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Stock & fast delivery: finished stocks for common sizes (6–120 mm) enable short lead times; custom forgings produced with 2–6 week lead times depending on volume.
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Quality controls: we provide EN/ASTM-compliant MTC (Type 3.1), hardness profile reports for carburized parts, and third-party inspection on request.
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Value-added services: peeling, turning, straightening, heat treatment (carburizing, quench & temper) and machining to tight tolerances.
Practical procurement pointers:
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Specify finish & tolerance early — "hot-rolled black" vs "peeled/turned" vs "ground/turned" drastically affects price.
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Ask for sample certificates (chemical + mechanical) before placing a PO.
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For critical components, arrange independent inspection during production.
FAQs
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Q: Can AISI 8620 be welded?
A: Yes; preheat (if section thick), use compatible filler (low hydrogen electrodes or matching alloy wires) and post-weld tempering when required to avoid hydrogen cracking and loss of toughness. -
Q: What case depth can be achieved?
A: Typically 0.5–2.5 mm in commercial carburizing; deeper cases (3+ mm) require longer cycles or special processes. Specify the required effective case depth on the PO. -
Q: Is 8620 magnetic?
A: Yes, 8620 is ferromagnetic in common conditions. -
Q: Can 8620 be through-hardened?
A: No. it is low carbon and intended for case hardening. Through-hardening requires higher carbon grades (e.g., 4140). -
Q: What tolerances are standard for hot-rolled rounds?
A: Refer to ASTM A29 (general requirements) and specific supplier catalogs; tolerances are looser for hot-rolled than for cold-finished (A108). -
Q: What inspection documents should be requested?
A: Mill Test Certificate (EN 10204 Type 3.1), hardness profiles after heat treatment, chemical analysis and any agreed NDT reports. -
Q: How does nickel content affect 8620?
A: Nickel improves core toughness and impact resistance after heat treatment. -
Q: Is 8620 suitable for high-temperature service?
A: Not optimized for sustained high temperatures; choose elevated-temperature alloy steels where creep resistance is required. -
Q: Can 8620 be cold-worked?
A: Light cold work is possible, but heavy deformation should be followed by stress relief or full anneal. -
Q: How to choose between buying domestic vs mill-direct from China?
A: For small quantities and urgent delivery, domestic distributors offer convenience; for larger orders (tons) mill-direct buys from China yield better per-ton economics but factor in inspection, shipping and duty.
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