UNS G88220 (SAE/AISI 8822 and 8822H) Alloy Steel Forgings
A nickel-chromium-molybdenum carburizing steel for heavy-duty gears, pinions and driveline parts, supplied as open-die forged bars, seamless rolled rings, blocks and gear blanks by Jiangyin Jiangnan Metal Co., Ltd.
Summary
UNS G88220 is the Unified Numbering System designation for SAE/AISI 8822, a low-carbon nickel-chromium-molybdenum alloy steel made for carburizing. It gives a hard, wear-resistant case over a tough, high-strength core, which is why it is specified for heavy-duty gears, ring-and-pinion sets, shafts and bearing components. The hardenability-guaranteed version, 8822H, carries its own number, UNS H88220.
- Type: Ni-Cr-Mo carburizing (case-hardening) alloy steel, about 0.20 to 0.25 % carbon.
- Designations: SAE 8822 = AISI 8822 = UNS G88220. The H-grade 8822H = UNS H88220.
- Governing specifications: SAE J404, SAE J1268 for hardenability bands, ASTM A29/A29M, ASTM A322. Forgings to ASTM A788.
- Condition in service: carburized, quenched and tempered to a case of 58 to 62 HRC over a tough core.
- Supplier: Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges UNS G88220 and 8822H into round bars, hollow bars, seamless rolled rings, blocks, discs and gear blanks, with EN 10204 3.1 or 3.2 certificates. Tel 0086-189-2135-9659, email sales@steelforgepieces.com.
What is UNS G88220?
UNS G88220 is a low-carbon nickel-chromium-molybdenum alloy steel meant for case hardening. In the UNS system the prefix G covers AISI and SAE carbon and alloy steels, and the four digits that follow repeat the SAE number. G88220 is therefore SAE/AISI 8822.
The SAE number itself describes the metallurgy. The leading 88 puts the steel in the Ni-Cr-Mo family; the trailing 22 means a nominal carbon content near 0.22 %. That carbon level is deliberately low. As delivered the steel is soft and tough, and the working surface comes later, from carburizing, which drives carbon into the outer layer so that quenching leaves a hard case on a ductile core.
Set against the far more common AISI 8620, grade 8822 carries roughly twice the molybdenum and more manganese. It therefore hardens deeper. 8822 still reaches full core strength in section sizes where 8620 runs out, and that is why it turns up on truck axle ring-and-pinion sets, planetary carriers and large industrial gearing rather than on small parts.
UNS G88220 and UNS H88220 are not the same number
Important. A number of published data sheets carry the heading UNS G88220 over a chemistry table that in fact belongs to 8822H. These are separate UNS numbers with different acceptance criteria, and ordering against the wrong one is a common reason for a mill certificate to be rejected at incoming inspection.
| Aspect | SAE/AISI 8822, UNS G88220 | SAE/AISI 8822H, UNS H88220 |
|---|---|---|
| What the UNS prefix means | G: AISI and SAE carbon and alloy steels | H: AISI and SAE H-steels, hardenability guaranteed |
| What is guaranteed | Chemical composition only | A hardenability band, set by Jominy end-quench limits, with composition ranges widened to suit |
| Composition ranges | Narrower | Wider on C, Mn, Ni and Cr |
| Primary reference | SAE J404, ASTM A29 | SAE J1268, ASTM A304 |
| When to specify it | General forgings and non-critical case-hardened parts | Gears and shafts where case depth and core hardness must repeat from heat to heat |
For production gearing, 8822H is usually the right call. A guaranteed Jominy band is what allows a heat treater to hold case depth and core hardness consistently from one melt to the next. Jiangyin Jiangnan Metal Co., Ltd. forges to either designation and states the applicable UNS number, specification and edition on the mill certificate.
Chemical composition of UNS G88220 and AISI 8822H
| Element | SAE 8822 (UNS G88220) | SAE 8822H (UNS H88220) | Role in the steel |
|---|---|---|---|
| Carbon, C | 0.20 to 0.25 | 0.19 to 0.25 | Held low so the core stays tough. Case carbon is added by carburizing |
| Manganese, Mn | 0.75 to 1.00 | 0.70 to 1.05 | Hardenability, and combines with sulfur |
| Silicon, Si | 0.15 to 0.35 | 0.15 to 0.35 | Deoxidiser, with slight strengthening |
| Nickel, Ni | 0.40 to 0.70 | 0.35 to 0.75 | Core toughness, particularly at low temperature |
| Chromium, Cr | 0.40 to 0.60 | 0.35 to 0.65 | Hardenability, and case hardness through carbides |
| Molybdenum, Mo | 0.30 to 0.40 | 0.30 to 0.40 | Deep hardenability, and resistance to temper embrittlement |
| Phosphorus, P | 0.035 max | 0.035 max | Residual, limited to protect toughness |
| Sulfur, S | 0.040 max | 0.040 max | Residual, limited to protect transverse ductility |
| Iron, Fe | Balance | Balance | Base metal |
The ranges above are the values commonly published for the two designations. Check them against the current edition of the governing standard, whether SAE J404, SAE J1268, ASTM A29/A29M or ASTM A304, and against the purchase order. Permissible product analysis tolerances are not the same as heat analysis limits, and standards are revised from time to time. Jiangyin Jiangnan Metal reports the actual heat analysis for every batch on the material certificate.
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.7 to 8.03 g/cm³ | 0.278 to 0.290 lb/in³ |
| Modulus of elasticity | 190 to 210 GPa | 27,557 to 30,458 ksi |
| Poisson's ratio | 0.27 to 0.30 | 0.27 to 0.30 |
| Thermal conductivity | about 44 W/m·K | about 305 BTU·in/hr·ft²·°F |
| Specific heat capacity | about 475 J/kg·K | about 0.114 BTU/lb·°F |
| Thermal expansion, 20 to 100 °C | about 11.5 × 10-6 /K | about 6.4 × 10-6 /°F |
Thermal values are typical for low-alloy Ni-Cr-Mo steels of this class. Treat them as design guidance, not as acceptance criteria.
Mechanical properties
8822 is a carburizing steel, so its mechanical properties depend on condition. A single tensile strength quoted for "8822" means little unless it says whether the figure refers to annealed bar, to the carburized case, or to the core beneath it.
| Condition | Tensile strength | Yield strength | Elongation (A₅) | Hardness |
|---|---|---|---|---|
| Annealed, as supplied for machining | 520 to 620 MPa 75 to 90 ksi | 330 to 400 MPa 48 to 58 ksi | 22 to 28 % | 150 to 190 HB |
| Normalised | 620 to 760 MPa 90 to 110 ksi | 400 to 500 MPa 58 to 73 ksi | 18 to 24 % | 180 to 230 HB |
| Core, after carburize, quench and temper | 1,000 to 1,300 MPa 145 to 189 ksi | 750 to 1,050 MPa 109 to 152 ksi | 10 to 15 % | 30 to 43 HRC |
| Case, after carburize, quench and temper | n/a | n/a | n/a | 58 to 62 HRC |
How to use this table. Actual values move with section size, quench severity, tempering temperature and case depth. Where a drawing calls out specific core properties, Jiangyin Jiangnan Metal forges test prolongations or sacrificial coupons from the same heat and the same heat-treatment load, so the results represent the part as delivered.
Heat treatment and carburizing practice
The route below is the practice Jiangyin Jiangnan Metal follows for UNS G88220 and 8822H forgings unless a customer specification says otherwise.
| Operation | Temperature | Medium and cooling | Purpose |
|---|---|---|---|
| Forging | 1,100 to 1,200 °C 2,010 to 2,190 °F | Finish above 900 °C, then air cool | Close porosity, refine the as-cast structure, develop grain flow |
| Normalising | 900 to 930 °C 1,650 to 1,705 °F | Still air | Even grain size before machining and carburizing |
| Annealing | 840 to 870 °C 1,545 to 1,600 °F | Slow furnace cool to 600 °C | Lowest hardness for deep machining |
| Carburizing | 900 to 930 °C 1,650 to 1,705 °F | Gas or vacuum, carbon potential about 0.9 to 1.1 % | Build case carbon. Effective case is typically 0.8 to 2.0 mm, depending on hold time |
| Direct or reheat quench | 820 to 850 °C 1,510 to 1,560 °F | Agitated oil | Transform case and core to martensite |
| Sub-zero treatment, optional | -70 to -80 °C | Cryogenic | Convert retained austenite where dimensional stability matters |
| Tempering | 150 to 200 °C 300 to 390 °F | Air cool | Relieve quench stress while holding a 58 to 62 HRC case |
| Stress relief, after rough machining | 550 to 650 °C 1,020 to 1,200 °F | Furnace or air cool | Reduce distortion during carburizing |
Practical notes
- Case depth scales with the square root of time. Doubling the effective case depth takes roughly four times the carburizing hold. Heavy truck ring gears in 8822H commonly run 14 to 22 hours at temperature.
- Distortion control matters more than peak hardness. Normalise, rough machine, stress relieve, then finish machine before carburizing. Large rings are best fixture-quenched.
- Molybdenum resists temper embrittlement, but prolonged exposure of the core between 375 and 575 °C is still worth avoiding.
- Do not weld after carburizing. Where welding is unavoidable in the low-carbon condition, preheat to 200 to 300 °C, use low-hydrogen consumables and stress relieve afterwards.
- Machinability in the annealed condition is roughly 65 to 70 % of AISI 1212 free-machining steel.
Equivalent and comparable grades
| System or country | Designation | Relationship |
|---|---|---|
| UNS, USA | G88220, and H88220 for the H-grade | Exact |
| SAE and AISI, USA | 8822, 8822H | Exact |
| BS, UK | 805A20, 805M20 | Close, and commonly cross-referenced |
| DIN and W.-Nr., Germany | 1.6543 (21NiCrMo2), 1.6523 (20NiCrMo2-2) | Nearest family, lower Mo, not a drop-in substitute |
| JIS, Japan | SNCM220, SNCM420 | Nearest family |
| GB, China | 20CrNiMo, 20CrNi2Mo | Nearest family |
| Closest SAE alternatives | 8620, 4320, 9310 | Same duty, different hardenability |
There is no exact international twin for 8822. The grades above are the nearest comparable materials, not certified equivalents. Any substitution should be approved by the design authority against the real duty, meaning section size, required case depth and core hardness, rather than from a table alone. Jiangyin Jiangnan Metal will review a drawing and advise on substitution at no cost.
Specifications this grade is ordered against
ASTM A29/A29M for general requirements on hot-wrought bars. ASTM A322 for alloy steel bars in standard grades. ASTM A304 for bars with hardenability requirements. ASTM A331 for cold-finished bars. ASTM A519 for mechanical tubing. ASTM A788/A788M for general requirements on steel forgings. SAE J404 for chemical compositions, SAE J1268 for hardenability bands and SAE J1397 for estimated mechanical properties. AMS 2759 and AMS 2762 cover heat treatment and carburizing of parts.
Applications of UNS G88220 forgings
Automotive and heavy truck
Ring-and-pinion sets, differential gears, axle shafts, transmission gears and planetary carriers.
Industrial gearboxes
Helical and bevel gear blanks, pinion shafts, spindles and gear rims for mill and kiln drives.
Off-highway and mining
Final-drive components, track-drive sprockets and high-torque couplings.
Wind and power transmission
Planet-gear blanks, carriers and internal ring gear forgings for gearbox stages.
Bearings and rollers
Case-hardened bearing races and heavy roller shells that need a deep, tough core.
Oil, gas and drilling
Drive components and wear-critical sub-assemblies where surface hardness meets shock loading.
UNS G88220 forged products supplied by Jiangyin Jiangnan Metal
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The company produces UNS G88220 and AISI 8822H to customer drawings in the forms below.
| Product form | Size range | Single-piece weight | Typical use |
|---|---|---|---|
| Forged round bars and shafts | Ø 80 to 1,200 mm, up to 8,000 mm long | 50 to 20,000 kg | Pinion shafts, spindles, axle stock |
| Square, rectangular, flat and hex bars | 100 to 1,000 mm across flats | 50 to 15,000 kg | Machined blocks, die holders |
| Seamless rolled rings | OD 200 to 4,000 mm, height up to 1,000 mm | 30 to 15,000 kg | Gear rims, bearing races, flanges |
| Forged rings, open die | OD up to 3,000 mm | 50 to 12,000 kg | Short-run and oversize rings |
| Hollow bars, sleeves, bushings, cylinders | OD 150 to 1,500 mm, ID from 60 mm | 50 to 15,000 kg | Housings, hubs, barrels, casings |
| Blocks, discs and plates | Thickness 50 to 800 mm, Ø up to 2,500 mm | 50 to 20,000 kg | Gear blanks, carriers, tooling plate |
| Gear shafts, pinion shafts, stepped shafts | Ø up to 1,000 mm | 100 to 15,000 kg | Drive trains, gearbox internals |
Delivery conditions: as-forged, rough machined with a 3 to 6 mm allowance, normalised, annealed, normalised and tempered, or proof machined and ultrasonically tested. Carburizing and finish grinding can be arranged through qualified partners on request.
Manufacturing route and quality control
Process route
Electric-arc furnace or converter steelmaking, ladle refining, vacuum degassing, ingot or continuous-cast bloom, reheating, open-die forging or ring rolling, heat treatment, rough machining, non-destructive testing, certification.
Testing and certification
- Chemical analysis by spectrometer, covering heat and product analysis
- Mechanical testing: tensile, Charpy V impact including -40 °C, and hardness in HB or HRC
- Ultrasonic testing to ASTM A388, EN 10228-3, SEP 1921 or a customer class
- Magnetic particle and dye penetrant to ASTM E1444 and ASTM E165
- Grain size and microstructure to ASTM E112, with inclusion rating to ASTM E45
- Jominy end-quench hardenability to ASTM A255, which is mandatory for 8822H
- Dimensional report with EN 10204 3.1 or 3.2 material certificates
- Third-party inspection by SGS, BV, TUV or Lloyd's can be arranged
Frequently asked questions about UNS G88220
Is UNS G88220 the same as AISI 8822H?
Not exactly. UNS G88220 is SAE/AISI 8822, which is controlled on chemical composition. AISI 8822H is the hardenability-guaranteed version and has its own number, UNS H88220, with slightly wider composition ranges and a required Jominy band. Many published data sheets label an 8822H chemistry table as UNS G88220, which is a common source of certificate disputes.
What is UNS G88220 steel used for?
It is a carburizing grade used for heavily loaded gearing and driveline parts: ring-and-pinion sets, differential and transmission gears, planetary carriers, pinion shafts, bearing races, and mining or wind gearbox components. It suits parts that need a hard wear surface over a core that stays tough in a thick section.
What hardness can 8822H reach?
After carburizing, quenching and low-temperature tempering the case typically reaches 58 to 62 HRC over a core of roughly 30 to 43 HRC. In the annealed condition supplied for machining the steel is around 150 to 190 HB.
What is the difference between 8822 and 8620?
Both are Ni-Cr-Mo carburizing steels, but 8822 carries about twice the molybdenum, 0.30 to 0.40 % against 0.15 to 0.25 %, plus more manganese and carbon. That gives 8822 higher hardenability, so it holds core strength in larger sections. For small, thin parts 8620 is usually more economical. For heavy truck and industrial gearing, 8822 or 8822H is specified.
Can UNS G88220 be used without carburizing?
Yes. It can be quenched and tempered as a through-hardening low-alloy steel, which gives useful core strength and toughness. Most applications still carburize it, because the low carbon content limits the surface hardness and wear resistance that through hardening alone can reach.
Is 8822 weldable?
In the low-carbon, pre-carburized condition it can be welded with a preheat of 200 to 300 °C, low-hydrogen consumables and post-weld stress relief. Welding after carburizing is not recommended, since the high-carbon case cracks readily and the heat destroys the hardened layer locally.
What standards cover UNS G88220 forgings?
Composition comes from SAE J404 or ASTM A29/A29M, and hardenability bands for the H-grade from SAE J1268 or ASTM A304. Bar products are usually ordered to ASTM A322, and forgings to the general requirements of ASTM A788/A788M plus the customer's own drawing or specification.
Who supplies UNS G88220 forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin City, Jiangsu Province, China that manufactures UNS G88220 and AISI 8822H as forged bars, seamless rolled rings, blocks, discs, sleeves and gear blanks to customer drawings, with EN 10204 3.1 or 3.2 certification and third-party inspection on request. The sales team can be reached on 0086-189-2135-9659 or at sales@steelforgepieces.com.
What is the minimum order quantity and lead time?
Jiangyin Jiangnan Metal accepts single-piece orders for open-die forgings, with no tonnage minimum for prototype or replacement parts. Lead time for standard forgings is typically 25 to 45 days from drawing approval, depending on size, heat-treatment route and testing scope.
How do I get a quotation for an 8822H forging?
Send a drawing, or a description covering grade and specification, finished or rough-machined dimensions, quantity, delivery condition, required testing and certification, and destination port. Jiangyin Jiangnan Metal answers most enquiries within one working day at sales@steelforgepieces.com.
Request a quotation for UNS G88220 or AISI 8822H forgings
Include these seven items and we can price the job without a second email:
- Grade and specification, for example AISI 8822H to ASTM A788, UNS H88220
- Product form: bar, ring, block, sleeve or shaft
- Dimensions, with machining allowance if rough machined
- Quantity, and whether this is a prototype or a repeat order
- Delivery condition: as-forged, normalised, annealed or proof machined
- Testing and certification: UT class, impact temperature, EN 10204 3.1 or 3.2
- Destination port and required delivery date
Email the RFQ to sales@steelforgepieces.com
Or call, WhatsApp or WeChat 0086-189-2135-9659
About the supplier
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory based in Jiangyin City, Jiangsu Province, China. The company manufactures forged bars, seamless rolled rings, forged rings, blocks, discs, sleeves, hollow bars, gear shafts and pinion shafts in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, including UNS G88220 (SAE/AISI 8822) and AISI 8822H (UNS H88220), supplied worldwide to customer drawings with EN 10204 3.1 or 3.2 material certification.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Business
- Open-die forging factory. Forged bars, rings, blocks and shafts
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone
- 0086-189-2135-9659
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
- Materials
- Carbon steel, alloy steel, tool steel, stainless steel, nickel alloys
How to cite this page
Jiangyin Jiangnan Metal Co., Ltd. (2026). UNS G88220 (SAE/AISI 8822 and 8822H) Alloy Steel Forgings: data sheet and supply. Retrieved from https://www.steelforgepieces.com/Alloy-Steel/UNS-G88220.html
References
- SAE J404, Chemical Compositions of SAE Alloy Steels. SAE International
- SAE J1268, Hardenability Bands for Carbon and Alloy H Steels.
- ASTM A29/A29M, Steel Bars, Carbon and Alloy, Hot-Wrought. ASTM International
- ASTM A322, Steel Bars, Alloy, Standard Grades.
- ASTM A788/A788M, Steel Forgings, General Requirements.
- ASM International, Alloy Digest SA-288: AISI 8822, Carburizing Alloy Steel.