Stainless Steel AM-350
UNS S35000 · also Alloy 350, Alloy 633
AM-350 (UNS S35000, also Alloy 350 / Alloy 633) is a semi-austenitic Cr-Ni-Mo stainless that develops strength through a combined transformation and precipitation cycle (SCT) rather than by cold work alone.
Reference datasheet — AM-350 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the A condition
AM-350 tempers and conditions
AM-350 is supplied in 7 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Stock condition for sheet, strip and bar — formable and weldable, then hardened by the user. | 390 | 1,100 | 40 | 210 HB | — |
Equalized 745 °C, refrigerated −75 °C, tempered 540 °C | Tougher hardened condition with better ductility and slightly higher temperature capability than H850. | 970 | 1,170 | 15 | 39 HRC | — |
Double aged | Pick when sub-zero equipment is unavailable or distortion must be minimised; slightly lower strength than SCT. | 1,030 | 1,240 | 13 | 41 HRC | — |
sub-zero cooled (−75 °C) and tempered 540 °C | Use when better toughness, weld-zone ductility and ~480 °C service are needed instead of peak strength. | 1,035 | 1,240 | 14 | 42 HRC | — |
Equalized 745 °C, refrigerated −75 °C, tempered 455 °C | Highest-strength standard hardened condition for bar and forgings where ductility can be traded for strength. | 1,100 | 1,310 | 12 | 44 HRC | — |
sub-zero cooled (−75 °C) and tempered 455 °C after 930 °C conditioning | Standard high-strength sheet/strip condition (AMS 5745) for airframe and engine hardware. | 1,170 | 1,380 | 11 | 46 HRC | — |
Cold rolled (≈50–60 % reduction) and tempered 455 °C, strip only | Ultra-high-strength thin strip for springs, diaphragms and clamps where forming is finished before heat treat. | 1,550 | 1,720 | 4 | 49 HRC | — |
What is AM-350?
AM-350 (UNS S35000, also Alloy 350 / Alloy 633) is a semi-austenitic Cr-Ni-Mo stainless that develops strength through a combined transformation and precipitation cycle (SCT) rather than by cold work alone. Engineers specify it where thin sheet, strip and small formed parts must be worked in the soft Condition A and then hardened to about 1100 MPa tensile with useful property retention to 425 °C. Conditions on file include A, H850, H1000, SCT850, SCT1000, DA and CRT. Forming and welding must precede hardening, machinability is low (score 38) and chloride corrosion resistance is below 304; AM-355 is the higher-carbon, higher-strength alternative. AM-350 has a density of 7.69 g/cm³ (0.278 lb/in³), lighter than 94% of stainless steel grades. It melts at 1,400°C (2,552 °F). AM-350 has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 54% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 200 GPa (29 Msi).
What is AM-350 used for?
- aircraft skin and structural sheet
- jet engine parts
- fasteners
Advantages
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
AM-350 properties
Typical room-temperature values for AM-350-A; bars are the position among stainless steel grades.
Physical3
AM-350 has a density of 7.69 g/cm³ (0.278 lb/in³), lighter than 94% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
AM-350 has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 54% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
AM-350 is rated for continuous service to 425°C (797 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
AM-350 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of AM-350 takes about 58 MJ of energy and emits 4.6 kg of CO₂ — more than 66% of stainless steel grades. Typical recycled content is 25%.
Manufacturability7
AM-350's machinability is fair (38/100, better than 63% of stainless steel grades); weldability good (65/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. AM-350 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AM-350
Is AM-350 easy to machine?
Machine in the annealed condition with sharp, rigid tooling, positive rake carbide, heavy feeds and flood coolant to avoid work-hardened glazing; hardened SCT/H tempers cut roughly like 45 HRC tool steel and often need grinding.
Can AM-350 be welded?
GTAW, plasma or EBW with matching AM-350 filler works well; keep heat input low and re-solution-treat plus re-harden after welding to restore full strength, since as-welded joints have austenitic, low-yield fusion zones.
Can AM-350 be formed, bent or molded?
Form, spin, draw or roll only in the annealed condition — it work-hardens rapidly by strain-induced martensite, so use intermediate anneals and generous bend radii; final shape must be set before the SCT/H cycle because hardening causes ~0.05–0.1 % dimensional change.
AM-350 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.07 – 0.11 | 0.09 |
| Mn | 0.5 – 1.25 | 0.85 |
| Si | ≤ 0.5 | 0.3 |
| Pimpurity limit | ≤ 0.04 | |
| Simpurity limit | ≤ 0.03 | |
| Cr | 16 – 17 | 16.5 |
| Ni | 4 – 5 | 4.3 |
| Mo | 2.5 – 3.25 | 2.75 |
| Nkey austenite stabiliser / strengthener | 0.07 – 0.13 | 0.1 |
| Fe | balance |
What surface finishes work on AM-350?
Passivate per AMS 2700/ASTM A967 after machining; takes a good mechanical polish, and can be shot-peened, black-oxided, electroplated (with low-hydrogen practice plus 190 °C bake) but is not anodized.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel AM-350 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S35000
- Trade names
- Alloy 350Alloy 633
How much does AM-350 cost?
AM-350 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
AM-350 — frequently asked
What is AM-350 used for?
AM-350 is typically used for aircraft skin and structural sheet, jet engine parts and fasteners. In short: formable then hardenable sheet; semi-austenitic PH stainless; useful strength to 425 °C.
What is the yield strength of AM-350?
AM-350 has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 54% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is AM-350 easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Machine in the annealed condition with sharp, rigid tooling, positive rake carbide, heavy feeds and flood coolant to avoid work-hardened glazing; hardened SCT/H tempers cut roughly like 45 HRC tool steel and often need grinding.
Can AM-350 be welded?
Yes — weldability is rated good (65/100). GTAW, plasma or EBW with matching AM-350 filler works well; keep heat input low and re-solution-treat plus re-harden after welding to restore full strength, since as-welded joints have austenitic, low-yield fusion zones.
What surface finishes work on AM-350?
Passivate per AMS 2700/ASTM A967 after machining; takes a good mechanical polish, and can be shot-peened, black-oxided, electroplated (with low-hydrogen practice plus 190 °C bake) but is not anodized.
Can AM-350 be formed, bent or molded?
Form, spin, draw or roll only in the annealed condition — it work-hardens rapidly by strain-induced martensite, so use intermediate anneals and generous bend radii; final shape must be set before the SCT/H cycle because hardening causes ~0.05–0.1 % dimensional change.
What is the maximum service temperature of AM-350?
AM-350 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AM-350-A and AM-350-CRT?
A is the default condition — stock condition for sheet, strip and bar — formable and weldable, then hardened by the user. CRT: ultra-high-strength thin strip for springs, diaphragms and clamps where forming is finished before heat treat. Yield strength is 390 MPa in A versus 1,550 MPa in CRT.
How much does AM-350 cost?
AM-350 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AMS 5548 — Steel, Corrosion and Heat Resistant, Sheet, Strip and Plate 16.5Cr-4.3Ni-2.8Mo (AM-350), Annealed — SAE International (2017)
- AMS 5745 / AMS 5746 — AM-350 SCT 850 and SCT 1000 conditions — SAE International (2016)
- ASTM A693 — Precipitation-Hardening Stainless Steel Plate, Sheet and Strip (UNS S35000) — ASTM International (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- MMPDS / MIL-HDBK-5 design allowables for AM-350 sheet — Battelle Memorial Institute (2021)
- AM-350 alloy technical data — Allegheny Technologies / AK Steel (2015)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.