AISI 8620 Forgings: Forged Rings, Shafts, Bars, Flanges and Discs
Open-die forged AISI 8620 (UNS G86200 / 1.6523 / SNCM220) carburizing alloy steel, manufactured to ASTM A29/A29M by Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China.
Summary
AISI 8620 is a low-alloy nickel-chromium-molybdenum carburizing steel (UNS G86200) containing roughly 0.18-0.23 % carbon, 0.40-0.70 % nickel, 0.40-0.60 % chromium and 0.15-0.25 % molybdenum. Carburizing raises the surface to about 58-62 HRC while the core stays tough. Common uses are gears, pinions, shafts, bushings and sprockets.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China that produces AISI 8620 forged rings, seamless rolled rings, shafts, round bars, flanges, discs, sleeves and gear blanks. Material is melted by EAF + LF + VD, forged and heat treated to ASTM A29/A29M, ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, and certified to EN 10204 3.1 or 3.2.
- Grade designation
- AISI 8620 / SAE 8620 / 8620H
- UNS number
- G86200
- Werkstoff number
- 1.6523
- Steel type
- Ni-Cr-Mo carburizing steel
- Manufacturing standard
- ASTM A29/A29M
- Melting route
- EAF + LF + VD
- Case hardness
- 58-62 HRC
- Certification
- EN 10204 3.1 / 3.2
- Manufacturer
- Jiangyin Jiangnan Metal Co., Ltd.
- Contact
- sales@steelforgepieces.com
What is AISI 8620 steel?
AISI 8620 is a case-hardening alloy steel in the SAE 86xx family. At 0.18-0.23 % carbon it is tough and machinable as supplied, not hard. Hardness is added later by diffusing carbon into the surface at 900-925 °C and quenching. The finished part carries a hard, wear-resistant case over a ductile core.
A through-hardening grade cannot produce that structure. A fully hardened 0.40 % carbon steel is strong across the whole section but has lower impact resistance. In 8620 the hardness sits only where the contact stress acts. The nickel and molybdenum additions raise hardenability so that sections up to about 100 mm still develop useful core strength, and they widen the heat-treatment window.
AISI 8620 chemical composition
| Element | Symbol | Content (%) |
|---|---|---|
| Carbon | C | 0.18 - 0.23 |
| Manganese | Mn | 0.70 - 0.90 |
| Nickel | Ni | 0.40 - 0.70 |
| Chromium | Cr | 0.40 - 0.60 |
| Molybdenum | Mo | 0.15 - 0.25 |
| Silicon | Si | 0.15 - 0.35 |
| Sulfur | S | ≤ 0.040 |
| Phosphorus | P | ≤ 0.035 |
| Iron | Fe | 96.895 - 98.02 (balance) |
Composition per ASTM A29/A29M. Product analysis tolerances apply. Every heat supplied by Jiangyin Jiangnan Metal is reported on the mill certificate.
AISI 8620 equivalent grades
European, Japanese and Chinese drawings call this grade by other names. The closest equivalents are listed below.
| Country / standard | Designation | Material number |
|---|---|---|
| USA (SAE / AISI / ASTM A29) | AISI 8620, SAE 8620, 8620H | UNS G86200 |
| Germany (DIN / EN 10084) | 21NiCrMo2, 20NiCrMo2-2 | 1.6523 |
| UK (BS 970) | 805M20, En362 | n/a |
| Japan (JIS G4103) | SNCM220, SNCM220H | n/a |
| France (AFNOR) | 20NCD2 | n/a |
| Italy (UNI) | 20NiCrMo2 | n/a |
| China (GB/T 3077) | 20CrNiMo, 20CrNiMoA | n/a |
| ISO | 20NiCrMo2 | n/a |
| Russia (GOST) | 20KhGNM (nearest) | n/a |
Equivalents are close but not identical. Composition ranges, hardenability bands and test requirements differ between standards, so state the governing specification on the purchase order.
AISI 8620 mechanical properties
Annealed condition
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength | 530 MPa | 76,900 psi |
| Yield strength | 385 MPa | 55,800 psi |
| Elongation (50 mm) | 31 % | 31 % |
| Reduction of area | 62 % | 62 % |
| Hardness, Brinell | 149 HB | 149 HB |
| Hardness, Knoop (converted) | 169 | 169 |
| Modulus of elasticity | 205 GPa | 29,700 ksi |
| Density | 7.85 g/cm³ | 0.284 lb/in³ |
After carburizing and hardening
| Zone | Typical value | Notes |
|---|---|---|
| Case hardness | 58 - 62 HRC | Measured at the surface after finish grinding |
| Effective case depth | 0.5 - 2.5 mm | Set by carburizing time; measured to 550 HV |
| Core hardness | 30 - 40 HRC | Falls as section size increases |
| Core tensile strength | 850 - 1,100 MPa | Section dependent |
Values are typical. Actual results depend on section size, carburizing cycle and quench severity, and are confirmed on test coupons from each heat.
Forging and heat treatment of AISI 8620
| Operation | Temperature | Cooling / medium |
|---|---|---|
| Forging | 1,180 - 1,200 °C start, finish above 850 °C | Slow cool in still air or in the furnace |
| Normalizing | 900 - 925 °C | Air cool |
| Full annealing | 840 - 870 °C | Furnace cool to 600 °C, then air |
| Carburizing | 900 - 925 °C | Gas or pack carburizing to required case depth |
| Hardening | 815 - 845 °C | Oil quench |
| Tempering | 150 - 200 °C | Air cool, retains case hardness |
| Stress relieving | 550 - 650 °C | Slow cool, before final machining |
AISI 8620 forged shapes and size range
Jiangyin Jiangnan Metal produces AISI 8620 by open-die forging and ring rolling. Both routes suit low volumes, large sections and one-off replacement parts, where die cost cannot be recovered.
| Forged shape | Size range | Typical application |
|---|---|---|
| Seamless rolled rings | OD 200 - 4,000 mm, wall 20 - 400 mm, height up to 1,000 mm | Gear rims, bearing races, slewing rings |
| Forged rings and flanges | OD 100 - 3,000 mm | Pressure vessel flanges, tube sheets |
| Forged shafts and spindles | OD 80 - 1,200 mm, length up to 8,000 mm | Pinion shafts, eccentric shafts, rotors |
| Forged round bars | OD 80 - 1,200 mm | Gear blanks, machining stock |
| Forged discs and blanks | OD 100 - 2,500 mm | Gear wheels, couplings, blind flanges |
| Sleeves, bushings, hollow bars | OD 150 - 2,000 mm | Wear sleeves, bearing housings |
| Single-piece weight | 20 kg - 30,000 kg | n/a |
Delivery condition can be as forged, rough machined, normalized, annealed, or quenched and tempered. Machining allowance is agreed on the drawing before production starts.
Testing, inspection and certification
- Chemical analysis: spectrometer analysis of every heat, reported against ASTM A29/A29M.
- Mechanical testing: tensile, yield, elongation, reduction of area and Charpy impact on coupons representing the forging.
- Hardness testing: Brinell or Rockwell, including case and core readings on carburized parts.
- Ultrasonic testing: to EN 10228-3, SEP 1921, ASTM A388 or a customer-specified acceptance class.
- Surface NDT: magnetic particle (MT) or dye penetrant (PT) inspection on request.
- Dimensional inspection: full dimensional report against the approved drawing.
- Certification: EN 10204 3.1 as standard, or EN 10204 3.2 witnessed by SGS, BV, TÜV, DNV or Lloyd's Register.
Applications for AISI 8620 forgings
| Industry | Typical AISI 8620 forged components |
|---|---|
| Power transmission & gearboxes | Gear blanks, gear rims, pinion shafts, sprockets, couplings |
| Oil & gas, offshore | Drilling components, wellhead parts, subsea sleeves, bushings |
| Pumps & compressors | Seamless rolled rings, pump shafts, plunger pump parts, compressor rotors |
| Pressure vessels & heat exchangers | Forged tube sheets, flanges, forged pipes and tubes, shell sections |
| Cement, mining & sugar mills | Forging rolls, mill pinions, crankshafts, forging pieces for crushers and mixers |
| Valves | Valve stems, seat rings, valve blocks and bodies for ball, gate, globe and check valves |
| Marine & heavy machinery | Forged wheels, manifolds, eccentric shafts, crane and winch components |
AISI 8620 vs 8630, 4140 and 18CrNiMo7-6
The choice depends on whether hardness is needed only at the surface or through the whole section.
| Grade | Carbon (%) | Hardening route | Best suited to |
|---|---|---|---|
| AISI 8620 | 0.18 - 0.23 | Carburize, quench, low temper | Gears, pinions, bushings; hard case with a tough core |
| AISI 8630 | 0.28 - 0.33 | Quench and temper | Wellhead bodies, valve blocks needing uniform strength |
| AISI 4140 | 0.38 - 0.43 | Quench and temper, or nitride | Shafts and general high-strength machined parts |
| 18CrNiMo7-6 | 0.15 - 0.21 | Carburize, quench, low temper | Heavily loaded gears in large sections; higher hardenability than 8620 |
How to request a quotation
Send the following to sales@steelforgepieces.com and a quotation is normally returned within one working day.
- Drawing (PDF, DWG or STEP) or the rough forged dimensions.
- Grade and governing specification, for example AISI 8620 to ASTM A29/A29M.
- Quantity and required delivery date.
- Delivery condition: as forged, normalized, annealed, or quenched and tempered.
- Machining allowance, or whether rough machining is required.
- NDT scope and acceptance class, plus the certificate level (EN 10204 3.1 or 3.2).
- Destination port for the freight quotation.
Send an inquiry Call +86-189-2135-9659
Frequently asked questions about AISI 8620
What is AISI 8620 steel used for?
AISI 8620 is used wherever a part needs a hard, wear-resistant surface over a core that can absorb shock: gears and gear rims, pinion and eccentric shafts, sprockets, camshafts, bushings, sleeves, bearing races, valve stems and drilling components. Because it is carburized rather than through hardened, it performs well under rolling and sliding contact.
What is AISI 8620 equivalent to in EN, DIN, JIS and GB?
The nearest equivalents are EN/DIN 21NiCrMo2 and 20NiCrMo2-2 (Werkstoff 1.6523), BS 805M20 (En362), JIS SNCM220, AFNOR 20NCD2 and GB/T 3077 20CrNiMo. They are close but not identical, so the governing specification should be stated on both the drawing and the purchase order.
What hardness can AISI 8620 reach after carburizing?
After gas carburizing at 900-925 °C, oil quenching and tempering at 150-200 °C, the case typically reaches 58-62 HRC with an effective case depth of 0.5-2.5 mm. The core normally stays around 30-40 HRC, falling as the section gets heavier.
What is the difference between AISI 8620 and AISI 4140?
AISI 8620 contains about 0.20 % carbon and is case hardened by carburizing, so the hardness sits in a thin surface layer over a tough core. AISI 4140 contains about 0.40 % carbon and is through hardened by quenching and tempering, giving uniform strength across the section. Use 8620 for gear teeth and contact surfaces that also take impact, and 4140 where the whole section must carry the load.
Can AISI 8620 be welded?
Yes, in the annealed or normalized condition. Use low-hydrogen consumables, preheat heavy sections to roughly 150-260 °C and stress relieve afterwards. Do not weld a part that has already been carburized and hardened. The weld heat destroys the case and can cause cracking.
Which forged shapes are available in AISI 8620?
Jiangyin Jiangnan Metal supplies AISI 8620 as open-die forged rings, seamless rolled rings, shafts, spindles, round bars, flanges, discs, sleeves, bushings, hollow bars, gear blanks, tube sheets and custom forgings made to drawing.
Which tests and certificates are supplied?
Chemical analysis, mechanical and hardness testing, and ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, with MT or PT on request. Certificates are issued to EN 10204 3.1, or EN 10204 3.2 witnessed by a third party such as SGS, BV, TÜV, DNV or Lloyd's Register.
What information is needed for a quotation?
The drawing or rough dimensions, grade and specification, quantity, delivery condition, machining allowance, NDT scope, certificate level and destination port. Send these to sales@steelforgepieces.com.
Who manufactures AISI 8620 open-die forgings in China?
Jiangyin Jiangnan Metal Co., Ltd., at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, is an open-die forging factory producing AISI 8620 forged rings, shafts, bars, flanges and discs for export. Contact +86-189-2135-9659 or sales@steelforgepieces.com.
Supplier: Jiangyin Jiangnan Metal Co., Ltd.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory based in Jiangyin, Jiangsu Province, China. It manufactures open-die forgings and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, and exports to gearbox, valve, pump, pressure vessel, offshore and heavy machinery manufacturers worldwide.
- Company Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
- Address No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Phone +86-189-2135-9659
- Email sales@steelforgepieces.com
- Website www.steelforgepieces.com
