AMS 6481 is an SAE Aerospace Material Specification covering a nitriding grade of premium aircraft-quality low-alloy steel, nominally 3 percent chromium, 1 percent molybdenum and 0.2 percent vanadium with 0.29 to 0.36 percent carbon, double vacuum melted and supplied as bars, forgings, mechanical tubing and forging stock. It is used mainly for nitrided bearings and gears running under heavy load and high speed at moderate temperature.

AMS 6481
32CrMoV12-10
W.Nr. 1.7765
32CDV13 / E32CDV13
AIR 9160
BOEHLER V361

AMS 6481 (3Cr-1Mo-0.2V) open-die forgings

Q: What is the chemical composition of AMS 6481?

AMS 6481 contains 0.29 to 0.36 percent carbon, 2.80 to 3.30 percent chromium, 0.70 to 1.20 percent molybdenum, 0.15 to 0.35 percent vanadium, 0.40 to 0.70 percent manganese and 0.10 to 0.40 percent silicon, with nickel restricted to 0.30 percent maximum, phosphorus to 0.015 percent and sulfur to 0.005 percent in the double vacuum melted product, the balance being iron.

Q: How is AMS 6481 heat treated?

AMS 6481 is hardened from about 950 degrees Celsius with an oil quench, tempered between 620 and 660 degrees Celsius to the required core strength, stress relieved at 540 to 580 degrees Celsius after rough machining, and gas nitrided at 490 to 530 degrees Celsius. The tempering temperature must stay at least 30 degrees Celsius above the nitriding temperature.

Q: Is AMS 6481 weldable?

AMS 6481 is not normally welded. It is an air-hardening 3 percent chromium steel that forms martensite in the heat-affected zone, and the parts made from it are fatigue critical. Where welding is unavoidable it requires preheat above 250 degrees Celsius, a low-hydrogen process and post-weld heat treatment below the tempering temperature, agreed in writing beforehand.

Seamless rolled rings, shafts, discs, sleeves and bar in double vacuum melted 3Cr-1Mo-0.2V nitriding steel, forged to drawing in Jiangyin, China.

Published 18 May 2016 Last reviewed 13 September 2026 Reviewed by the metallurgy department, Jiangyin Jiangnan Metal Co., Ltd.

AMS 6481 is the SAE Aerospace Material Specification for a nitriding grade of premium aircraft-quality low-alloy steel, nominally 3 % chromium, 1 % molybdenum and 0.2 % vanadium with 0.29 to 0.36 % carbon, supplied as bars, forgings, mechanical tubing and forging stock in the double vacuum melted condition for bearing applications. The same chemistry is designated 32CrMoV12-10, Werkstoff 1.7765 and 32CDV13. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges AMS 6481 into seamless rolled rings, shafts, discs, sleeves and blocks to customer drawings, heat treats them in house, and certifies each piece to EN 10204 3.1 or 3.2.

Specification: AMS 6481ESAE, 2022 revision
Carbon: 0.29 to 0.36 %3.0 Cr, 1.0 Mo, 0.2 V
Melting route: VIM + VARdouble vacuum melted
Core tensile, Q+T: 950 to 1280 MPa138 to 186 ksi
Nitrided surface: 700 HV5 mintypically 850 to 1000 HV
Certification: EN 102043.1 / 3.2

What is AMS 6481?

AMS 6481 is a specification issued by SAE International rather than a trade name. It covers steel bars, forgings, mechanical tubing and forging stock in a nitriding grade of premium aircraft-quality low-alloy steel, 3Cr-1Mo-0.2V with 0.29 to 0.36 % carbon, double vacuum melted, for bearing applications. The current revision is AMS6481E, published in 2022. It replaced AMS6481D of 2017, which replaced AMS6481C of 2012. Jiangyin Jiangnan Metal Co., Ltd. asks buyers to state the revision on the purchase order, since the revision sets the testing and reporting scope rather than the chemistry.

Three terms in the specification title define the grade. Nitriding grade means the surface is hardened by diffusing nitrogen into it at about 500 degrees C instead of by quenching. Premium aircraft quality sets the cleanliness, macrostructure and inspection requirements. Double vacuum melted means vacuum induction melting followed by vacuum arc remelting of the resulting electrode, which reduces the oxide inclusion content to the level needed for consistent rolling contact fatigue life.

Why the grade is nitrided instead of case hardened

A carburised part has to be quenched to harden, and the quench distorts it. An AMS 6481 part is hardened and tempered before nitriding, and the nitriding cycle runs below the tempering temperature, so movement during nitriding is small. This matters most on large-diameter thin-section rings, where the grinding allowance needed to correct quench distortion can exceed the case depth available. AMS 6481 provides a hard wear surface over a tough core without a hardening quench after machining.

Function of the alloying elements

Chromium at 2.80 to 3.30 % forms the fine nitrides that produce case hardness and carries most of the core hardenability. Molybdenum at 0.70 to 1.20 % forms nitrides of its own and suppresses temper embrittlement, which allows the steel to be tempered above the nitriding temperature. Vanadium at 0.15 to 0.35 % refines the prior austenite grain size and adds a secondary hardening response. The nitriding behaviour of the grade depends on all three additions together rather than on the chromium content alone.

AMS 6481 designations and equivalents

This steel is ordered under at least six different names. The designations below describe the same nominal chemistry, and Jiangyin Jiangnan Metal Co., Ltd. accepts purchase orders under any of them.

Table 1. AMS 6481 designations and equivalent specifications
System	Designation	Note
SAE (USA)	AMS 6481, current revision AMS6481E	Double vacuum melted, premium aircraft quality, bearing applications
EN (Europe)	32CrMoV12-10	Same nominal analysis
Werkstoff / SEL	1.7765	German material number
AFNOR / AIR 9160 (France)	32CDV13, and E32CDV13 for the vacuum arc remelted version	The E prefix denotes VAR
Common literature name	32CrMoV13, 3Cr-Mo-V nitriding steel	Used in bearing and gear research papers
Mill trade name	BOEHLER V361	VIM + VAR, stated by the mill as related to AMS 6481

Cross-reference compiled by Jiangyin Jiangnan Metal Co., Ltd. from the published specifications and mill datasheets. The equivalences are close but not identical. Where a purchase order names AMS 6481, Jiangyin Jiangnan Metal Co., Ltd. certifies to AMS 6481 and lists the equivalents on the certificate for reference only.

AMS 6481 chemical composition

The analysis below is the range Jiangyin Jiangnan Metal Co., Ltd. forges to for AMS 6481 orders. Every heat is supplied with a ladle analysis on the mill certificate, and a product analysis on the finished forging can be added on request.

Table 2. AMS 6481 / 32CrMoV12-10 chemical composition, weight %
Element	Minimum	Maximum	Function
Carbon (C)	0.29	0.36	Core strength and hardenability, held low enough to retain core toughness
Silicon (Si)	0.10	0.40	Deoxidiser, small increase in tempering resistance
Manganese (Mn)	0.40	0.70	Hardenability, combines residual sulfur
Chromium (Cr)	2.80	3.30	Principal nitride former, hardenability through heavy sections
Molybdenum (Mo)	0.70	1.20	Nitride former, suppresses temper embrittlement
Vanadium (V)	0.15	0.35	Grain refinement, secondary hardening at nitriding temperature
Nickel (Ni)	-	0.30	Residual, restricted because it does not form nitrides
Copper (Cu)	-	0.10	Residual, restricted for hot workability
Phosphorus (P)	-	0.015	Restricted, segregates to grain boundaries and lowers toughness
Sulfur (S)	-	0.005	Tightly restricted, sulfide inclusions initiate rolling contact fatigue
Iron (Fe)	Balance		Base metal

Source: Jiangyin Jiangnan Metal Co., Ltd., AMS 6481 forging specification, compiled from AMS 6481 and the vacuum melted mill analyses for 32CrMoV12-10 / 1.7765. Single melted material to AIR 9160 permits wider phosphorus and sulfur limits, P 0.025 % and S 0.020 % maximum. The tighter limits above apply to the double vacuum melted product required by AMS 6481. The governing purchase specification takes precedence.

AMS 6481 mechanical properties

AMS 6481 is supplied in a soft condition so that the part can be machined. Service properties are developed afterwards by hardening, tempering and nitriding. Both sets of values are given below.

Table 3. AMS 6481 properties by condition, sections up to 80 mm diameter
Condition	Tensile Rm	Elongation A, min	Impact, min	Hardness
Annealed, as supplied	-	-	-	248 HB max
Cold finished supply limit, AMS 6481E	862 MPa max (125 ksi)	-	-	Equivalent hardness
Hardened, tempered at 640 degrees C min	950 to 1100 MPa 138 to 160 ksi	14 %	12 J	300 to 330 HB core
Hardened, tempered at 620 degrees C min	1080 to 1280 MPa 157 to 186 ksi	12 %	10 J	340 to 380 HB core
Nitrided surface, either temper	-	-	-	700 HV5 min, typically 850 to 1000 HV

Room-temperature values for quenched, tempered and nitrided parts up to 80 mm diameter, as applied by Jiangyin Jiangnan Metal Co., Ltd. Elongation is measured on 5.65 root S0. Impact values are ISO V-notch minima. The tempering table does not fix a 0.2 % proof strength. Where a drawing states a minimum Rp0.2, Jiangyin Jiangnan Metal Co., Ltd. certifies against the customer figure. Heavier sections are agreed per order, because the tempering response falls with section size.

Nitrided case hardness profile

The chart and table below give a typical microhardness traverse on a transverse section after hardening, tempering and a deep gas nitriding cycle at 500 to 520 degrees C. Case depth is set by cycle time and is agreed for each order.

Table 4. Hardness depth data plotted above
Depth, mm	0.02	0.10	0.20	0.30	0.45	0.60	0.80
Hardness, HV0.3	950	880	800	700	560	430	385

Indicative profile published by Jiangyin Jiangnan Metal Co., Ltd., measured to ISO 6507 on a transverse section. Case depth and surface hardness are set by the nitriding cycle and confirmed against the drawing for each order.

Physical properties

Table 5. Indicative physical properties of the 3Cr-Mo-V nitriding class at room temperature
Property	Value	Note
Density	7.85 g/cm3	0.284 lb/in3
Modulus of elasticity	210 GPa	30.5 million psi
Coefficient of thermal expansion	12.5 micrometre per metre per degree C	20 to 200 degrees C
Thermal conductivity	37 W/m.K	at 100 degrees C
Specific heat	460 J/kg.K	at 20 degrees C
Electrical resistivity	0.22 micro-ohm.m	22 micro-ohm.cm
Magnetic response	Ferromagnetic	In all supply conditions
Practical service ceiling	400 degrees C	Below the tempering temperature. The nitrided case is stable to about 450 degrees C

Indicative values published by Jiangyin Jiangnan Metal Co., Ltd. for the 3Cr-Mo-V low-alloy nitriding class. Physical constants are not certified on the material certificate and should not be used as acceptance criteria.

How AMS 6481 is heat treated

The thermal operations are always carried out in the order below. Jiangyin Jiangnan Metal Co., Ltd. runs forging, annealing, hardening, tempering and stress relief in house on instrumented furnaces and records the charts against the works order. Nitriding is carried out by a qualified partner plant when the customer specifies it, and the nitriding chart is attached to the certificate.

Table 6. AMS 6481 thermal cycle applied by Jiangyin Jiangnan Metal Co., Ltd.
Operation	Temperature	Cooling	Purpose
Forging	Charge 1130 to 1180 degrees C, finish above 900 degrees C	Slow cool in still air or in the furnace	Break down the cast structure. At 3 % chromium the steel air hardens, so forgings left in a draught can crack
Annealing	840 to 870 degrees C, or subcritical 680 to 710 degrees C	Furnace cool below 600 degrees C	Machinable condition, 248 HB maximum
Hardening	930 to 960 degrees C, typically 950 degrees C	Oil quench	Fully martensitic core
Tempering	620 to 660 degrees C	Air	Sets core tensile strength and must remain above the later nitriding temperature
Stress relief	540 to 580 degrees C after rough machining	Furnace cool	Releases machining stress so the part does not move during nitriding
Gas nitriding	490 to 530 degrees C, 20 to 120 h	Furnace cool in atmosphere	Builds the case, with cycle time setting the depth

Works practice published by Jiangyin Jiangnan Metal Co., Ltd. Confirm against the governing purchase specification, which may narrow any of these bands. The tempering temperature must exceed the nitriding temperature by at least 30 degrees C, otherwise the core softens during the nitriding cycle.

AMS 6481 forgings produced 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. Open-die working and ring rolling suit AMS 6481 because demand is dominated by ring and shaft geometries in small batches, where closed die tooling would not pay back. Product forms produced in AMS 6481 are seamless rolled rings, forged shafts, discs, sleeves, hollow bars, blocks, gear blanks, pinion shafts and forged rings.

Table 7. Works forging range published by Jiangyin Jiangnan Metal Co., Ltd.
Parameter	Range	Note
Diameter	100 to 6000 mm	Across all grades worked at the plant
Length	100 to 12000 mm	Shafts and drawn sections
Unit weight	10 to 15000 kg	Single-piece forging weight
Hydraulic press	4500 t	Main open-die press
Forging hammers	1 t, 3 t, 6 t, 9 t	Four hammers for smaller sections
Ring rolling mills	3 m and 6 m	Seamless rolled rings, including bearing ring blanks
Melting routes available	ESR, VIM + ESR + VAR	AMS 6481 billet is procured double vacuum melted, VIM + VAR, as the specification requires
Certification	EN 10204 3.1 / 3.2	3.2 witnessed by a third party on request

These are the figures Jiangyin Jiangnan Metal Co., Ltd. publishes for its open-die works as a whole. AMS 6481 is a vacuum melted aerospace grade, so the practical size envelope is set by remelt ingot availability and is confirmed per enquiry rather than quoted as a fixed maximum.

Delivery condition is annealed as standard, supplied rough machined with an agreed allowance or finish machined to drawing. Hardening and tempering to a stated core strength is available in house, and parts can be shipped ready for the customer to nitride where the nitriding source is controlled by the end user.

How an AMS 6481 forging is produced

The route below is the eight-stage sequence used by Jiangyin Jiangnan Metal Co., Ltd. Each stage depends on the one before it.

Billet sourcing and PMI Double vacuum melted billet is received with the melt certificate stating the VIM and VAR heat numbers, then verified by positive material identification before release to the forge.
Preheat and soak The billet is through-heated to 1130 to 1180 degrees C and held until core and surface temperatures equalise.
Upsetting and cogging The billet is upset and cogged under the 4500 t press to a forging ratio of at least 4:1, which breaks down the cast dendritic structure and orients the flow lines along the load path.
Punching, expanding and ring rolling Ring blanks are punched, expanded over a saddle mandrel and finished on the 3 m or 6 m ring rolling mill. Shafts are drawn down between flat dies with controlled bite.
Controlled reheats and slow cooling The forging is reheated as required so that deformation always finishes above 900 degrees C, then cooled slowly. At 3 % chromium the steel air hardens, and fast cooling after forging can cause cracking.
Annealing The forging is annealed to below 248 HB, which gives a machinable structure and removes forging stresses before any metal is cut.
Rough machining and ultrasonic testing The forging is rough machined to a testable surface, then examined volumetrically by ultrasonic testing to ASTM A388 against the acceptance class stated on the order. Aerospace bearing stock is normally inspected to a tighter class than general engineering work.
Testing and certification Heat chemistry, tensile and yield strength, elongation, impact energy, hardness, grain size to ASTM E112, inclusion rating to ASTM E45 and the heat treatment charts are documented on an EN 10204 3.1 or 3.2 inspection certificate.

Standards that apply to AMS 6481 forgings

Table 8. Specifications referenced on an AMS 6481 order
Standard	Scope
AMS 6481	Governing material specification: composition, melting route, quality, supply condition and testing
AMS 2259	Composition tolerances permitted on check analysis
AMS 2301	Cleanliness and magnetic particle inspection procedure for premium aircraft-quality steel
AMS 2300	Premium aircraft-quality cleanliness and magnetic particle inspection, where specified in place of AMS 2301
ASTM A751	Chemical analysis methods for steel products
ASTM A388	Ultrasonic examination of heavy steel forgings
ASTM E112	Determination of average grain size
ASTM E45	Determination of inclusion content
ISO 6507	Vickers hardness test, used for the nitrided case profile
AIR 9160	French aerospace specification for 32CDV13 and E32CDV13
EN 10204 3.1 / 3.2	Inspection certificate reporting actual test results for the material delivered

Reference list compiled by Jiangyin Jiangnan Metal Co., Ltd. The issue of each document in effect on the date of the purchase order forms part of the contract. Buyers should obtain the current AMS 6481 revision from SAE International rather than relying on a supplier summary.

AMS 6481 compared with other nitriding and bearing steels

The table below compares AMS 6481 with the grades most often considered in its place. Values are typical rather than specification minima.

Table 9. AMS 6481 against comparable grades
Property	AMS 6481 32CrMoV12-10	Nitralloy 135M AMS 6470	31CrMoV9 1.8519	AISI 4340 AMS 6414	M50 AMS 6491
Chromium	2.8 to 3.3 %	1.6 %	2.3 to 2.7 %	0.7 to 0.9 %	4 %
Molybdenum	0.7 to 1.2 %	0.35 %	0.15 to 0.25 %	0.2 to 0.3 %	4.25 %
Other	V 0.15 to 0.35 %	Al 1.13 %	V 0.10 to 0.20 %	Ni 1.65 to 2.0 %	V 1 %
Melting route	VIM + VAR required	Air or VAR	Air melted	Air, VAR or VIM + VAR	VIM + VAR
Hardening mechanism	Nitriding	Nitriding	Nitriding	Through hardening	Through hardening
Core tensile, typical	950 to 1280 MPa	900 to 1100 MPa	900 to 1100 MPa	1100 to 1800 MPa	Through hard, 60 to 64 HRC
Nitrided surface	850 to 1000 HV	Up to 1100 HV, more brittle case	800 HV	550 to 650 HV	Not nitrided as standard
Core toughness	High	Moderate	Moderate to high	High	Low
Typical use	Aero-engine and gearbox bearings, gears, shafts	General nitrided wear parts, spindles	Industrial gears, extruder screws	Landing gear, structural shafts	High-temperature engine bearings

Comparison compiled by Jiangyin Jiangnan Metal Co., Ltd. for grade selection. Verify against the governing standard before substituting a grade. Nitralloy 135M reaches a higher surface hardness because of its aluminium content, but the case is more brittle. M50 is through hardened to a higher surface hardness with much lower core toughness. AMS 6481 is specified where surface hardness, core toughness and dimensional stability are all required in the same part.

Applications for AMS 6481 forgings

Table 10. Typical service and forged components in AMS 6481
Sector	Service	Forged components
Aero engines	Mainshaft and accessory bearings at high speed and moderate temperature	Bearing inner and outer ring blanks, seamless rolled rings, sleeves
Aerospace transmissions	Accessory gearboxes and helicopter main gearboxes	Gear blanks, pinion shafts, planet carriers, discs
Industrial gas turbines	Rotating shafts and bearing housings	Shafts, hollow bars, rings
Motorsport and performance automotive	Heavily loaded rotating parts where distortion cannot be ground out	Crankshafts, gear blanks, drive shafts
Precision machine tools	Spindles requiring surface hardness with dimensional stability	Spindle shafts, sleeves, bushings
General engineering	High-strength parts that use the core properties without nitriding	Shafts, blocks, flange blanks

Application list published by Jiangyin Jiangnan Metal Co., Ltd. Flight-critical bearing and gear parts are normally procured against an approved-source list held by the engine manufacturer. Buyers should confirm source approval requirements before placing an AMS 6481 order with any supplier.

What to include in an AMS 6481 forging enquiry

Jiangyin Jiangnan Metal Co., Ltd. can quote from a sketch, but a complete enquiry is quoted faster and more accurately.

Table 11. AMS 6481 enquiry checklist
Item	Effect on price and lead time
Drawing or rough dimensions	Sets the input billet weight, which dominates cost in a double vacuum melted grade
AMS 6481 revision	Fixes the testing and reporting scope
Supply condition	Annealed, hardened and tempered to a stated core strength, or ready for nitriding
Required core properties	Determines the tempering temperature and therefore the nitriding ceiling
Case depth and surface hardness	Sets the nitriding cycle length, often the longest single operation in the route
Test package	Ultrasonic class, grain size, inclusion rating, magnetic particle inspection, third-party witness
Quantity and delivery date	Vacuum remelted billet is usually procured to order, and batching changes lead time

Frequently asked questions about AMS 6481

What is AMS 6481?

AMS 6481 is an SAE Aerospace Material Specification covering a nitriding grade of premium aircraft-quality low-alloy steel, nominally 3 % chromium, 1 % molybdenum and 0.2 % vanadium with 0.29 to 0.36 % carbon, double vacuum melted and supplied as bars, forgings, mechanical tubing and forging stock. It is used mainly for nitrided bearings and gears running under heavy load and high speed at moderate temperature.

What is the current revision of AMS 6481?

The current revision is AMS6481E, published in 2022. It replaced AMS6481D of 2017, which replaced AMS6481C of 2012. Jiangyin Jiangnan Metal Co., Ltd. asks buyers to state the revision on the purchase order, because the revision governs the testing and reporting scope rather than the chemistry.

What is AMS 6481 equivalent to?

AMS 6481 corresponds to EN 32CrMoV12-10, Werkstoff number 1.7765, and the French AIR 9160 designations 32CDV13 and E32CDV13, where the E prefix denotes the vacuum arc remelted version. It appears in the literature as 32CrMoV13 and is sold by mills under trade names including BOEHLER V361. The equivalences are close but not identical, so Jiangyin Jiangnan Metal Co., Ltd. certifies to whichever specification the order names.

Why is AMS 6481 double vacuum melted?

Rolling contact fatigue cracks in bearing steel start at oxide inclusions. Vacuum induction melting followed by vacuum arc remelting removes dissolved gases and reduces the inclusion population by an order of magnitude compared with air melting, which lowers the scatter in bearing fatigue life. AMS 6481 therefore makes double vacuum melting a requirement rather than an option.

What is the chemical composition of AMS 6481?

AMS 6481 contains 0.29 to 0.36 % carbon, 2.80 to 3.30 % chromium, 0.70 to 1.20 % molybdenum, 0.15 to 0.35 % vanadium, 0.40 to 0.70 % manganese and 0.10 to 0.40 % silicon, with nickel restricted to 0.30 % maximum, phosphorus to 0.015 % and sulfur to 0.005 % in the double vacuum melted product, the balance being iron.

How hard is AMS 6481 after nitriding?

The nitrided surface of AMS 6481 reaches at least 700 HV5 and typically 850 to 1000 HV, over a core hardened and tempered to between 950 and 1280 MPa tensile strength. A deep nitriding cycle at 500 to 520 degrees C gives a nitriding hardness depth of about 0.6 mm. The exact depth is set by cycle time and agreed per order.

How is AMS 6481 heat treated?

AMS 6481 is hardened from about 950 degrees C with an oil quench, tempered between 620 and 660 degrees C to the required core strength, stress relieved at 540 to 580 degrees C after rough machining, and gas nitrided at 490 to 530 degrees C. The tempering temperature must stay at least 30 degrees C above the nitriding temperature, otherwise the core softens during the nitriding cycle.

Can AMS 6481 be supplied as seamless rolled rings?

Yes. Jiangyin Jiangnan Metal Co., Ltd. produces AMS 6481 seamless rolled rings on 3 m and 6 m ring rolling mills, which is the usual form for bearing ring blanks and gear blanks. Rings are punched and expanded over a saddle mandrel before rolling, so the grain flow follows the circumference.

What sizes can be forged in AMS 6481?

The open-die works of Jiangyin Jiangnan Metal Co., Ltd. covers 100 to 6000 mm diameter, 100 to 12000 mm length and 10 to 15000 kg single-piece weight, using a 4500 t hydraulic press, hammers of 1, 3, 6 and 9 tonnes, and 3 m and 6 m ring rolling mills. For AMS 6481 the practical envelope is set by the size of vacuum remelted ingot available, so it is confirmed per enquiry.

Is AMS 6481 weldable?

AMS 6481 is not normally welded. It is an air-hardening 3 % chromium steel with a strong tendency to form martensite in the heat-affected zone, and the parts made from it are fatigue critical. Where a repair or fabrication weld is unavoidable, it requires preheat above 250 degrees C, a low-hydrogen process and a post-weld heat treatment below the tempering temperature, all agreed in writing before the work starts.

What certification is supplied with AMS 6481 forgings?

Jiangyin Jiangnan Metal Co., Ltd. issues an EN 10204 3.1 inspection certificate, or 3.2 witnessed by a third party on request, reporting heat chemistry, tensile and yield strength, elongation, impact energy, hardness, grain size to ASTM E112, inclusion rating to ASTM E45, ultrasonic test results to ASTM A388 and the heat treatment charts.

Who supplies AMS 6481 open-die forgings in China?

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing AMS 6481 seamless rolled rings, shafts, discs, sleeves, blocks and gear blanks to customer drawings. Enquiries reach the company at sales@steelforgepieces.com or +86 189 2135 9659.

What information is needed to quote an AMS 6481 forging?

Send the drawing or rough dimensions, the AMS 6481 revision, the supply condition, the required core strength, the case depth and surface hardness if the part is to be nitrided, the test package and the quantity. Jiangyin Jiangnan Metal Co., Ltd. replies to complete enquiries at sales@steelforgepieces.com.

Glossary

Double vacuum melting (VIM + VAR): Vacuum induction melting to produce a clean electrode, followed by vacuum arc remelting of that electrode. Removes dissolved gases and non-metallic inclusions, and is mandatory under AMS 6481.
Nitriding: Diffusing nitrogen into the surface of a finished, hardened and tempered part at about 500 degrees C to form hard alloy nitrides. No quench is involved, so distortion is small.
Nitriding hardness depth (Nht): The depth below the surface at which hardness has fallen to the core hardness plus 50 HV. The standard way of stating case depth on a drawing.
Compound layer: The thin iron nitride layer at the extreme surface, also called the white layer. Hard and brittle, and usually ground away on bearing races, leaving the diffusion zone beneath.
Rolling contact fatigue: Sub-surface fatigue caused by repeated Hertzian contact, the life-limiting mechanism in bearings. Sensitive to inclusion content, which is why vacuum remelted steel is specified.
Premium aircraft quality: An SAE quality level defined by melting route, macrostructure, cleanliness and inspection requirements, above aircraft quality and above commercial quality.
Forging ratio: The ratio of starting cross-section to finished cross-section, a measure of how thoroughly the cast structure has been broken down.
Seamless rolled ring: A ring made by punching a hole in an upset billet and rolling the wall between a mandrel and a driven roll, giving circumferential grain flow and no weld.
EN 10204 3.1: An inspection certificate issued by the independent inspection department of the manufacturer, reporting actual test results for the material delivered. Under 3.2 the results are witnessed by a third party.

Data source and reuse

This page is published by Jiangyin Jiangnan Metal Co., Ltd. and reviewed by its metallurgy department. The technical data may be reused under CC BY 4.0 with attribution.

Jiangyin Jiangnan Metal Co., Ltd. (2026). "AMS 6481 (3Cr-1Mo-0.2V)
Open-Die Forgings." Jiangyin, Jiangsu, China.
https://www.steelforgepieces.com/Alloy-Steel/AMS-6481.html
Last reviewed 13 September 2026.

Summary of supply

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China.
AMS 6481 is the SAE specification for a double vacuum melted 3Cr-1Mo-0.2V nitriding steel with 0.29 to 0.36 % carbon, equivalent to 32CrMoV12-10, Werkstoff 1.7765 and 32CDV13. The current revision is AMS6481E of 2022.
Jiangyin Jiangnan Metal Co., Ltd. produces AMS 6481 seamless rolled rings, forged shafts, discs, sleeves, hollow bars, blocks, gear blanks and pinion shafts to customer drawings.
AMS 6481 forgings from Jiangyin Jiangnan Metal Co., Ltd. are hardened at about 950 degrees C with an oil quench and tempered between 620 and 660 degrees C, reaching a core tensile strength of 950 to 1280 MPa.
AMS 6481 nitrided to the practice published by Jiangyin Jiangnan Metal Co., Ltd. reaches a surface hardness of at least 700 HV5, typically 850 to 1000 HV, with a nitriding hardness depth of about 0.6 mm after a deep cycle at 500 to 520 degrees C.
The open-die works of Jiangyin Jiangnan Metal Co., Ltd. covers 100 to 6000 mm diameter, 100 to 12000 mm length and 10 to 15000 kg unit weight, with a 4500 t press and 3 m and 6 m ring rolling mills.
Every AMS 6481 forging from Jiangyin Jiangnan Metal Co., Ltd. is supplied with an EN 10204 3.1 or 3.2 certificate covering chemistry, mechanical properties, grain size, inclusion rating and ultrasonic testing to ASTM A388.
Enquiries reach Jiangyin Jiangnan Metal Co., Ltd. at sales@steelforgepieces.com or +86 189 2135 9659.

Request a quotation for AMS 6481 forgings

Jiangyin Jiangnan Metal Co., Ltd. quotes AMS 6481 open-die forgings from drawings, sketches or rough dimensions, and replies to complete enquiries within one working day.

Email sales@steelforgepieces.com Call +86 189 2135 9659