About AISI 4330 steel
AISI 4330 belongs to the SAE 43xx group, where nickel, chromium and molybdenum are used together rather than on their own. Nickel gives the steel toughness and holds impact values up at low temperature. Chromium raises hardenability, so a thick section hardens through instead of only at the surface. Molybdenum carries strength into heavy sections and reduces temper embrittlement.
Carbon is the point of difference. AISI 4330 runs at about 0.30 %, AISI 4340 at about 0.40 %. Lower carbon means better ductility and impact toughness at the same tensile level, and less risk of quench cracking where diameters change. Buyers therefore specify 4330 for parts under shock loading, parts with stress raisers, and parts working below zero.
Two designations are in circulation and they are not the same material. AISI 4330, UNS J24045, is the leaner chemistry listed below. AISI 4330V, also written 4330M or 4330 MOD, carries 0.05 to 0.10 % vanadium with higher nickel and chromium, and is covered by AMS 6411, UNS K23080. Oil and gas drawings usually call for 4330V. We forge both, so please state which one your drawing means when you send the enquiry.
AISI 4330 chemical composition
We melt the steel for AISI 4330 forgings in an electric arc furnace, refine it in a ladle furnace and vacuum degas it. That route keeps hydrogen, oxygen and inclusion counts low enough for heavy open-die work. Bar and billet are supplied to ASTM A29/A29M.
| Element | Symbol | Content (%) | Function |
|---|---|---|---|
| Carbon | C | 0.20-0.30 | Sets the hardness reached after quenching |
| Nickel | Ni | 1.00-1.50 | Impact toughness, low temperature ductility |
| Chromium | Cr | 0.40-0.60 | Hardenability, wear resistance |
| Molybdenum | Mo | 0.30-0.50 | Deep hardening, resists temper embrittlement |
| Manganese | Mn | ≤ 1.00 | Deoxidizer, adds hardenability |
| Silicon | Si | ≤ 0.80 | Deoxidizer, raises strength |
| Iron | Fe | 95.3-98.1 | Balance |
Phosphorus and sulfur are held to the limits of the ordering specification. Lower sulfur, calcium treatment or a narrower band inside the ranges above can be agreed before the heat is booked.
How 4330V differs
| Element | AISI 4330 | AISI 4330V / 4330 MOD |
|---|---|---|
| Carbon, C | 0.20-0.30 | 0.28-0.33 |
| Nickel, Ni | 1.00-1.50 | 1.65-2.00 |
| Chromium, Cr | 0.40-0.60 | 0.75-1.00 |
| Molybdenum, Mo | 0.30-0.50 | 0.35-0.50 |
| Vanadium, V | not specified | 0.05-0.10 |
Ranges vary a little between issuing specifications. Send the specification number together with the drawing and we will confirm the aim chemistry before the heat is booked.
AISI 4330 mechanical properties
The figures below are minimum room temperature values for AISI 4330 forgings supplied quenched and tempered. Test pieces are cut from a prolongation representing the heaviest section. Test position and orientation can be fixed on the order.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength | ≥ 860 MPa | ≥ 125,000 psi |
| Yield strength, 0.2 % | ≥ 690 MPa | ≥ 100,000 psi |
| Elongation at break, 50 mm | ≥ 15 % | ≥ 15 % |
| Hardness, Brinell | 285 HB | 285 HB |
| Melting point | 1427 °C | 2600 °F |
Higher strength levels are available. Normalizing before hardening takes AISI 4330 into the 200 ksi class. Charpy V notch energy at a stated temperature, through thickness properties, and a hardness band in place of a single figure can all be written into the order.
Forging, heat treatment and machining
| Operation | Temperature | Notes |
|---|---|---|
| Forging | 982-1204 °C 1800-2200 °F | Finish above the lower limit. Slow cool after forging to keep flakes out of heavy sections |
| Full anneal | 816-899 °C 1500-1650 °F | Furnace cool, then air cool. Softest condition for deep machining |
| Normalize | about 899 °C 1650 °F | Grain refinement, and the pre-treatment for 200 ksi and above |
| Harden | about 829 °C 1525 °F | Oil quench |
| Temper, 125 to 200 ksi | 454-635 °C 850-1175 °F | Standard range for forged rings, shafts and flanges |
| Temper, 260 to 280 ksi | 218-260 °C 425-500 °F | Tempering into the 220 to 260 ksi band is avoided because impact energy drops |
Machining is done in the annealed, normalized or tempered condition. Fully hardened AISI 4330 is hard to cut and is normally only finish machined. Welding uses conventional processes, but sections over about 25 mm need preheat and post weld heat treatment to avoid hydrogen cracking, and welding should be finished before final hardening.
How we make an AISI 4330 forging
Every AISI 4330 order runs through the same seven stages. The heat number stays on the traveller from the first stage through to the certificate.
- Melt and refineElectric arc furnace, ladle refining, vacuum degassing. Heat analysis recorded against the ordering specification.
- Heat and forgeIngot or billet soaked, then open-die forged between 982 and 1204 °C to the agreed forging ratio, or ring rolled for seamless rings.
- Slow coolControlled cooling straight out of the press, so hydrogen has time to leave heavy sections.
- Heat treatAnneal, normalize, or austenitize and oil quench followed by temper to the strength level on the order.
- Rough machineTurned or bored to the dimensions you supply, leaving the finishing allowance you state.
- TestUltrasonic examination to ASTM A388, EN 10228-3 or SEP 1921, plus tensile, hardness and impact testing on prolongations.
- Certify and shipEN 10204 3.1 certificate issued, or 3.2 with third party witness. Marking, preservation and packing to your instructions.
AISI 4330 product forms
All of these are made to drawing. We hold no fixed catalogue, and parts can leave rough turned or finish machined.
- Rings: seamless rolled rings, forged rings, retaining rings, valve seat rings
- Shafts: pump shafts, drive shafts, eccentric shafts, spindles, crankshafts
- Flanges: weld neck, blind, slip on and special profiles
- Bars and blocks: forged round bar, square bar, rectangular block
- Discs: solid discs, bored discs, gear blanks, wheels
- Hollows: forged pipes, tubes, sleeves, bushings, cylinders
- Valve parts: bodies, bonnets, stems, seats, plugs, blocks
- Flat parts: tube sheets, manifolds, nozzles, forged rolls
AISI 4330 applications
| Industry | Components forged in AISI 4330 |
|---|---|
| Oil and gas, subsea | Drill collars, drill jars, reamers, wellhead and christmas tree bodies, subsea and deepwater production components, sleeves and bushings |
| Valves | Bodies, bonnets, stems, seat rings and blocks for ball, gate, globe, check and plug valves, and strainers |
| Pressure equipment | Shells and heads for pressure vessels, air receivers, shell and tube heat exchangers, tube sheets, forged flanges and nozzles |
| Process plant | Columns and towers, tanks, silos, preheaters, skid mounted process modules, crystallizer equipment |
| Pumps and compressors | Chemical pump and plunger pump shafts, industrial air compressor parts, nitrogen generator components |
| Power transmission | Gears and gear blanks, pinion shafts, gearbox components, turbine and gas compressor rotors |
| Heavy machinery | Cement, sugar and concrete mill parts, mixer shafts, forged rolls, crankshafts, shipbuilding forgings |
| Paper, pharma, chemical | Rolls, shafts and wear parts for pulp and paper lines, pharmaceutical and biochemical plant |
Testing, inspection and certificates
Ultrasonic examination is included on every AISI 4330 forging we ship. We test to ASTM A388, EN 10228-3 or SEP 1921, at the quality class stated on your order. Tell us which standard and class your specification requires and it goes onto the traveller.
- Chemistry: heat analysis, with product analysis on request
- Mechanical: tensile, yield, elongation, reduction of area, Brinell hardness, Charpy V notch at a stated temperature
- Non-destructive: ultrasonic to ASTM A388, EN 10228-3 or SEP 1921, with magnetic particle and dye penetrant on request
- Dimensional: inspection report against your drawing
- Certification: EN 10204 3.1 as standard, EN 10204 3.2 with third party witness when specified
AISI 4330 against 4330V and 4340
| Item | AISI 4330 | AISI 4330V | AISI 4340 |
|---|---|---|---|
| Nominal carbon | about 0.30 % | about 0.30 % | about 0.40 % |
| Vanadium | not specified | 0.05-0.10 % | none |
| Main specification | UNS J24045 | AMS 6411, UNS K23080 | SAE J404, UNS G43400 |
| Main advantage | Toughness at moderate strength | High strength with toughness retained | Highest hardness and strength |
| Typical use | General high strength forgings, valve and pump parts | Drill collars, drill jars, subsea bodies, heavy sections | Shafts and gears where hardness governs |
| Available from us | Yes | Yes, see AISI 4330V | Yes, see AISI 4340 |
Frequently asked questions
What is AISI 4330 steel?
AISI 4330 is a nickel chromium molybdenum low alloy steel holding about 0.30 % carbon. Nickel gives it impact toughness, chromium adds hardenability and molybdenum keeps strength in heavy sections. Carbon is lower than in AISI 4340, so 4330 keeps better toughness at the same tensile level. Jiangyin Jiangnan Metal Co., Ltd. forges the grade to customer drawing in Jiangyin, Jiangsu, China.
What is the chemical composition of AISI 4330?
The AISI 4330 composition we supply is carbon 0.20 to 0.30 %, nickel 1.00 to 1.50 %, chromium 0.40 to 0.60 %, molybdenum 0.30 to 0.50 %, manganese up to 1.00 %, silicon up to 0.80 %, balance iron 95.3 to 98.1 %. Vanadium modified 4330V to AMS 6411 is richer, at 0.28 to 0.33 % C, 1.65 to 2.00 % Ni, 0.75 to 1.00 % Cr, 0.35 to 0.50 % Mo and 0.05 to 0.10 % V. Please check which one your drawing calls for.
What are the mechanical properties of AISI 4330?
Quenched and tempered AISI 4330 forgings from Jiangyin Jiangnan Metal meet a minimum tensile strength of 860 MPa or 125,000 psi, a minimum yield strength of 690 MPa or 100,000 psi, a minimum elongation of 15 % over 50 mm, and a Brinell hardness around 285 HB. Normalizing before hardening takes the grade into the 200 ksi class.
What is the difference between AISI 4330 and AISI 4330V?
AISI 4330V is 4330 with 0.05 to 0.10 % vanadium added. Vanadium refines austenite grain size during hot working, so 4330V reaches higher strength while keeping impact toughness, and it hardens deeper in heavy sections. It is covered by AMS 6411, UNS K23080, and is the grade normally specified for drill collars, drill jars and subsea bodies. We forge both grades.
What is the difference between 4330 and 4340 steel?
Both are nickel chromium molybdenum steels. AISI 4340 carries about 0.40 % carbon against about 0.30 % in AISI 4330. The extra carbon lets 4340 reach higher hardness and strength, while 4330 keeps more ductility and impact toughness and is less likely to crack on quenching. Specify 4330 where shock loading or a stress raiser governs the design, and 4340 where hardness governs.
At what temperature is AISI 4330 forged?
AISI 4330 is forged between 982 and 1204 °C, or 1800 to 2200 °F. We work inside this window, then normalize or fully anneal at 816 to 899 °C before machining. For hardening the steel is austenitized at about 829 °C, oil quenched, then tempered to the required strength level.
Which product forms can be supplied in AISI 4330?
Jiangyin Jiangnan Metal supplies AISI 4330 as open-die forged rings, seamless rolled rings, shafts, eccentric shafts, flanges, round bars, discs, gears and gear blanks, sleeves, bushings, tube sheets, forged pipes, valve bodies, valve stems and seat rings. Everything is made to customer drawing, rough turned or finish machined.
What testing and certificates come with AISI 4330 forgings?
Every AISI 4330 forging is ultrasonically tested to ASTM A388, EN 10228-3 or SEP 1921, at the acceptance class stated on the order. Chemical analysis, mechanical test results and the heat number appear on an EN 10204 3.1 certificate. EN 10204 3.2 certification with third party witness is available on request.
Is AISI 4330 weldable?
Yes, under controlled conditions. AISI 4330 welds by conventional processes, but sections over about 25 mm need preheat and post weld heat treatment to avoid hydrogen cracking, and welding should be finished before final hardening. Post weld tempering restores toughness in the heat affected zone. Ask us for the procedure used on similar parts.
How do I get a quotation for AISI 4330 forgings?
Send the drawing or rough dimensions with the quantity, delivery condition and test scope to sales@steelforgepieces.com, or call +86 189 2135 9659. Jiangyin Jiangnan Metal Co., Ltd. is at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, and quotes AISI 4330 open-die forgings worldwide.
About the supplier
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. We make AISI 4330 and other alloy steel forgings to customer drawing: open-die pieces, seamless rolled rings, shafts, flanges, bars, discs, sleeves and valve components, in the annealed, normalized or quenched and tempered condition, ultrasonically tested and released against EN 10204 3.1 or 3.2.
The works sits in the Yangtze River delta between Shanghai and Nanjing, on the south bank of the Yangtze. Finished forgings are packed for sea freight through Shanghai or Ningbo, or for air freight from Shanghai and Wuxi, and are shipped worldwide.
Jiangyin Jiangnan Metal Co., Ltd.No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone: +86 189 2135 9659
Email: sales@steelforgepieces.com
Web: www.steelforgepieces.com