AISI 416 Forgings (UNS S41600 / 1.4005)
AISI 416 (UNS S41600, EN 1.4005, X12CrS13, JIS SUS 416) is a free-machining martensitic stainless steel containing 12.0 to 14.0 % chromium, a maximum of 0.15 % carbon and a minimum of 0.15 % sulphur. Its machinability rating of 85 % is the highest of any stainless steel; the manganese sulphide inclusions that give that rating also lower formability, weldability and corrosion resistance below grade 410. It hardens by oil quenching and tempering to 26 to 32 HRC and is specified for valve stems and seats, pump and motor shafts, gears, studs and screw-machine work.
Jiangyin Jiangnan Metal Co., Ltd. melts, forges, heat treats, machines and tests grade 416 on one site at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, so each certificate traces a finished part back to its own melt number rather than to a purchased billet. Forged bars, hollow bars, seamless rolled rings, discs, blocks, shafts and valve components. Enquiries: sales@steelforgepieces.com, +86-189-2135-9659.
- UNSS41600
- EN number1.4005
- StructureMartensitic
- Chromium12.0-14.0 %
- Sulphur0.15 % min
- Machinability85 %
- Hardness, H+T26-32 HRC
- Forging range1149-1232 °C
- MagneticYes
01Designations and international equivalents
Any of the designations below is accepted on an enquiry as the same material. State the governing specification on the order so the aim analysis is set correctly at the furnace, because the aerospace variants run a different chromium and sulphur window.
| System | Designation |
|---|---|
| AISI / SAE | 416, Type 416, Grade 416, Alloy 416 |
| UNS | S41600 |
| Euronorm | 1.4005 / X12CrS13 |
| Old British | 416S21, En 56AM, also 416S29, 416S37, 416S41, En 56BM, En 56CM |
| Swedish SS | 2380 |
| Japanese JIS | SUS 416 |
| AFNOR | Z12CF13 |
| Aerospace | AMS 5610, Type 1 selenium bearing and Type 2 |
| Product standards | ASTM A582, A484, A314, MIL-W-52263, QQ-S-763C, QQ-S-764. ASTM A473 covers stainless steel forgings including the martensitic grades |
Carpenter Technology sold this grade originally as No. 5 and records it as the first free-machining stainless steel.
02Chemical composition
| Limit | C | Mn | Si | P | S | Cr | Mo |
|---|---|---|---|---|---|---|---|
| Minimum | – | – | – | – | 0.15 | 12.0 | – |
| Maximum | 0.15 | 1.25 | 1.00 | 0.06 | – | 14.0 | 0.60 |
AZoM and Rolled Alloys agree on these limits. Carpenter gives 12.00 to 14.00 % chromium with 0.150 % sulphur minimum. Aircraft Materials lists the AMS 5610 variants at 11.50 to 13.50 % chromium with sulphur to 0.40 % maximum, plus a selenium-bearing Type 1 at 0.18 to 0.35 % Se.
03Mechanical properties
| Condition or tempering temperature | Tensile Rm (MPa) | 0.2 % proof (MPa) | Elongation (% in 50 mm) | Hardness (HB) | Charpy V (J) |
|---|---|---|---|---|---|
| Annealed, Condition A | 517 | 275 | 30 | 262 | – |
| Condition T | 758 | 586 | 18 | 248-302 | – |
| Tempered 204 °C | 1340 | 1050 | 11 | 388 | 20 |
| Tempered 316 °C | 1350 | 1060 | 12 | 388 | 22 |
| Tempered 427 °C, avoid | 1405 | 1110 | 11 | 401 | low |
| Tempered 538 °C, avoid | 1000 | 795 | 13 | 321 | low |
| Tempered 593 °C | 840 | 705 | 19 | 248 | 27 |
| Tempered 650 °C | 796 | 670 | 17.5 | 253 | 38 |
Annealed figures are typical for Condition A of ASTM A582. In Condition T the Brinell range is specified while the other values are typical only. AZoM states that these values may not apply to forms other than bar, including forgings and wire, so order acceptance values should be agreed in the purchase specification. Carpenter gives a parallel quench and temper curve for 1 in. bar hardened at 982 °C and oil quenched: 1344 MPa and 390 HB at a 149 °C temper, falling to 758 MPa and 225 HB at 650 °C.
Tempering band to avoid
Do not temper between 400 and 580 °C, given by Carpenter as 399 to 566 °C. Impact strength and corrosion resistance both fall in that band, which is why no Charpy value is quoted at 427 and 538 °C.
04Physical properties
| Property | Value |
|---|---|
| Density | 7800 kg/m3, 0.276 lb/in3 |
| Elastic modulus | 200 GPa |
| Mean thermal expansion | 9.9 µm/m·°C (0-100 °C), 11.0 (0-315 °C), 11.5 (0-538 °C) |
| Thermal conductivity | 24.9 W/m·K at 100 °C, 28.7 W/m·K at 500 °C |
| Specific heat, 0-100 °C | 460 J/kg·K |
| Electrical resistivity | 570 nΩ·m |
| Melting point | 2714 °F, approximately 1490 °C |
| Magnetic response | Ferromagnetic in every condition, annealed as well as hardened |
Density, modulus, expansion, conductivity, specific heat and resistivity from AZoM. Imperial density and melting point from Rolled Alloys.
05Forging and heat treatment practice
| Operation | Practice |
|---|---|
| Hot forging | Heat uniformly to 1149-1232 °C (2100-2250 °F), forge, air cool. Cool heavy forgings slowly in dry lime or ashes. Trim hot where possible, otherwise anneal and trim cold. Do not forge below 927 °C (1700 °F). Not recommended for severe upsetting. (Carpenter) |
| Full annealing | 815-900 °C for half an hour, cool at 30 °C per hour, then air cool. Carpenter maximum softness practice 816-900 °C with furnace cooling, approximately 155 HB. (AZoM, Carpenter) |
| Sub-critical annealing | 650-760 °C, air cool, approximately 187 HB. Best machining condition. (AZoM, Carpenter) |
| Hardening | 925-1010 °C (1700-1850 °F), soak, oil quench, then temper without delay. (AZoM, Carpenter) |
| Tempering | To the required hardness, outside the 400-580 °C band. (AZoM, Carpenter) |
| Scaling limit | Intermittent service to 760 °C, continuous service to 675 °C per AZoM; Carpenter gives 649 °C continuous. Do not load above the tempering temperature if strength must be retained. |
| Welding | Not recommended by Carpenter. Where unavoidable, preheat 200-300 °C, use 410 low-hydrogen electrodes or 309 filler, then re-harden, anneal or stress relieve at 650-675 °C. Rolled Alloys advises a post-weld anneal near 790 °C (1450 °F). |
| Cold working | Withstands limited cold work; cold upsetting is not recommended. 416Se, with selenium replacing sulphur, behaves better in cold forming. (Carpenter) |
Our own practice on this grade is to equalise the section before pulling to top heat, finish the last blows above 950 °C, and control the cooling rate on heavy sections so the martensite forms without quench cracking. Every piece is annealed or sub-critically annealed before machining, so the customer receives it in a condition that cuts freely.
06Machining behaviour
Grade 416 is specified when metal removal dominates the cost of the part. Sulphur is added deliberately, forming manganese sulphide inclusions that break the chip and allow high cutting speeds. Carpenter records that 416 machines in automatic screw machines at 135 to 155 surface feet per minute with high-speed tooling, that carbide tooling runs two to three times those speeds, and that the grade remains commercially machinable at around 34 HRC. The same source notes that the low frictional properties of 416 reduce scratching, galling and seizing, which is why it has long been used for pump shafts and valve stems running in packings.
07Corrosion resistance and service limits
Suitable duty
Mild atmospheres, fresh water, steam, ammonia, many petroleum products and organic materials, and several mild acid environments, where 26 to 32 HRC covers the strength requirement.
Unsuitable duty
Chloride and marine environments, because of the high sulphur content. Carpenter rates salt spray, nitric, sulphuric, phosphoric and acetic acid exposure as restricted, does not recommend the grade for welding, and Aircraft Materials states it is not recommended for vessels containing gases or liquids under high pressure.
Corrosion resistance is reached only on a hardened, clean and smooth surface free of scale, lubricant and drawing compound, with passivation considered after machining. Overall resistance is below that of the non-free-machining martensitic grades, the austenitic grades and 17 % chromium ferritic 430.
When another grade is the better choice
AZoM lists grade 410 where corrosion resistance and formability matter more than machinability, 303 where availability matters and heat treatment is not required, and 182 where soft magnetic performance is needed for solenoid shafts. Within our own stainless programme the usual alternatives are AISI 431 for higher strength with better corrosion resistance, 1.4034 / X46Cr13 and AISI 440C for higher hardness and wear resistance, and CA6NM where weldability and toughness govern. For chloride, sour or strongly acidic duty, duplex, super duplex or nickel alloy forgings are the correct route.
08Forged products supplied in grade 416
| Product form | Range | Typical use |
|---|---|---|
| Forged bars | Round, square, rectangular, flat and hexagon | Screw-machine stock, fastener stock, machining blanks |
| Hollow bars and sleeves | Bored from solid forged blanks to 1600 mm bore by 10 000 mm | Bushings, barrels, cases, hubs, housings |
| Rings | Seamless rolled and upset-and-punched, 50 mm to 6000 mm outside diameter | Seat rings, retaining rings, flanged rings |
| Discs, blocks, plates | Machined to 5000 mm swing | Closure plates, die blanks, valve bodies |
| Shafting | Horizontal turning to 14 m between centres | Pump and motor shafts, spindles, lead screws |
| Valve components | Near net shape | Valve stems, seats, seat rings, bodies, bonnets |
Supplied as-forged with machining allowance, proof machined for ultrasonic inspection, or finish machined to drawing. Delivery standards for this grade include ASTM A473 for stainless steel forgings, ASTM A582 and A484 for bar, and EN 10250-4 for open-die stainless forgings.
09Manufacturing and inspection
| Department | Equipment |
|---|---|
| Melting | 25 t electric arc furnace, 25 t and 50 t ladle furnaces, 30 t and 60 t vacuum oxygen decarburisation, 60 t maximum heat size. VIM, VAR and ESR available for remelted grades |
| Forging | Hydraulic open-die presses of 6300 t, 4000 t and 2000 t; hammers of 5 t, 3 t, 2 t, 1 t and 750 kg |
| Ring rolling | Radial-axial mills of 6 m, 3 m and 1 m |
| Heat treatment | 14 furnaces, car-bottom chambers to 8000 by 2000 by 2000 mm, two 15 m well-type furnaces for vertical quenching of long shafts |
| Machining | Vertical lathes to 5000 mm swing, horizontal lathes to 14 m between centres, CNC deep-hole drilling to 1600 mm by 10 000 mm |
| Testing | OES chemistry, infrared carbon and sulphur, PMI, tensile to ASTM A370, Charpy to minus 60 °C, ultrasonic to ASTM A388 and EN 10228-3, magnetic particle to ASTM E709, metallography to ASTM E112 |
| Approvals and certification | CCS, BV, DNV, LR and NK approved. EN 10204 3.1 as standard; 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's own inspector on request |
| Commercial terms | Maximum single piece 30 000 kg. Minimum order 10 kg with no minimum piece count. Lead time 20 to 60 days, grade 416 at the lower end since no remelting step is required |
Operating since 1997 with 460 staff, including 9 senior engineers, 32 intermediate engineers and 140 technicians. Exports to North America, Europe, the Middle East and Asia Pacific.
10Frequently asked questions
What is AISI 416 stainless steel?
A free-machining martensitic stainless steel with 12.0 to 14.0 % chromium, 0.15 % carbon maximum and 0.15 % sulphur minimum. It is magnetic, hardenable by oil quenching and tempering to 26 to 32 HRC, and has the highest machinability of any stainless steel at an 85 % rating.
What is the equivalent of AISI 416?
UNS S41600, EN 1.4005, X12CrS13, BS 416S21 or En 56AM, SS 2380, JIS SUS 416, AFNOR Z12CF13 and AMS 5610 all designate this grade. The AMS 5610 variants run a slightly different chromium and sulphur window, so quote the specification on the order.
What is the forging temperature of grade 416?
Heat uniformly to 1149 to 1232 °C and do not forge below 927 °C. Cool heavy forgings slowly in dry lime or ashes. Carpenter does not recommend the grade for severe upsetting.
Can AISI 416 be welded?
Carpenter does not recommend welding this grade, because the high sulphur content promotes hot cracking. Where a weld cannot be avoided, preheat to 200 to 300 °C, use 410 low-hydrogen electrodes or 309 filler, and follow with re-hardening, annealing or a stress relief at 650 to 675 °C. Rolled Alloys advises a post-weld anneal near 790 °C. If the part must be welded, consider CA6NM instead.
Why should tempering between 400 and 580 °C be avoided?
Impact strength and corrosion resistance both drop in that band. Charpy V values of 20 to 22 J at 204 to 316 °C and 27 to 38 J at 593 to 650 °C sit either side of a trough, so tempering is specified outside the range.
Is AISI 416 suitable for seawater?
No. The sulphur addition makes it unsuitable for chloride and marine environments, and Carpenter rates salt spray resistance as restricted. For marine shafting choose AISI 431, or duplex and super duplex grades for aggressive chloride service.
Can Jiangyin Jiangnan Metal supply 416 forgings to ASTM A473 with a 3.1 certificate?
Yes. We are an open-die forging factory in Jiangyin, Jiangsu, China, supplying grade 416 forged bars, hollow bars, seamless rolled rings, discs, blocks, shafts and valve parts against ASTM A473, ASTM A582 and EN 10250-4, with EN 10204 3.1 certificates as standard and 3.2 third-party witnessed certificates on request. Minimum order 10 kg. Contact sales@steelforgepieces.com or +86-189-2135-9659.
Request a quotation for AISI 416 forgings
Send the grade or specification, the dimensions or a drawing, the quantity, the delivery condition, the heat treatment and testing requirements, and the certification plus destination port. Quotations are normally returned within two working days. Jiangyin lies between Shanghai and Nanjing on the south bank of the Yangtze, 30 km from Wuxi Shuofang International Airport and 160 km from the Shanghai airports. Customer audits and third-party inspections are welcome.
Jiangyin Jiangnan Metal Co., Ltd.No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
Phone, WhatsApp and WeChat: +86-189-2135-9659
Email: sales@steelforgepieces.com
11Sources and notes
Where the published sources differ, for example on the continuous scaling temperature or on the chromium band of the AMS 5610 variants, both figures are given rather than averaged. The data on this page is engineering guidance, not a warranty of properties for a particular application. Acceptance values for a specific order are those written into the purchase specification and reported on the mill certificate.
- AZoM, Stainless Steel, Grade 416 (UNS S41600). Composition, mechanical and physical property tables, heat treatment, alternative grades.
- Carpenter Technology, CarTech 416 Stainless (No. 5) datasheet. Forging practice, annealing, quench and temper curve, machining speeds, corrosion ratings, welding position.
- Rolled Alloys, 416 Stainless data sheet. Composition limits, imperial density, melting point, post-weld anneal.
- Aircraft Materials, Stainless Steel 416 (AMS 5610) technical data sheet. Specification cross reference and the pressure-vessel restriction.
Datasheet MAT-DS/416 · Revision 2 · Published 30 September 2026 · Reviewed 1 October 2026 · Technical sales department, Jiangyin Jiangnan Metal Co., Ltd.
Cite this page: Jiangyin Jiangnan Metal Co., Ltd. (2026). AISI 416 Forgings (UNS S41600 / 1.4005): composition, properties, forging and heat treatment. steelforgepieces.com/Stainless-Steel/AISI-416.html