Steel 13-8Mo
UNS S13800 · ASTM 5629
13-8Mo (UNS S13800, AMS 5629) is a martensitic precipitation-hardening stainless steel powder with a low-carbon, vacuum-melted chemistry that gives higher transverse toughness and cleanliness than 17-4PH at comparable hardness.
Reference datasheet — 13-8Mo 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 H1000 condition
13-8Mo tempers and conditions
13-8Mo is supplied in 10 conditions, soft to hard. H1000 is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Double overaged 760 °C + 621 °C | Maximum ductility/toughness and lowest hardness; used for sour-service and heavy-section forgings. | 655 | 896 | 21 | 30 HRC | 1.9 % IACS |
Solution annealed | Supply/stock condition for machining, forming or subsequent aging; not a final service condition. | 827 | 1,000 | 12 | 33 HRC | — |
L-PBF as-built | Green-state AM parts before solution + aging; use only for fit checks or low-duty hardware. | 870 | 1,100 | 10 | 34 HRC | 1.7 % IACS |
Overaged 621 °C (1150 °F) for 4 h, maximum toughness | Highest-toughness single-step age; best SCC and impact behaviour of the standard tempers. | 896 | 1,034 | 19 | 34 HRC | — |
Aged 593 °C (1100 °F) for 4 h | Over-aged condition for tough, damage-tolerant parts around 1100 MPa UTS. | 1,034 | 1,138 | 17 | 37 HRC | 1.8 % IACS |
Solution treated + aged 566 °C / 4 h | Good compromise when higher toughness and chloride-SCC margin matter more than peak strength. | 1,207 | 1,276 | 15 | 42 HRC | — |
Aged 552 °C (1025 °F) for 4 h | Slightly softer than H1000 with improved impact toughness; common for actuator and shaft parts. | 1,276 | 1,345 | 14 | 43 HRC | — |
L-PBF + solution treat + H1000 age | Standard AM post-process route giving near-wrought H1000 properties (add HIP for fatigue-critical parts). | 1,330 | 1,420 | 12 | 45 HRC | 1.7 % IACS |
H1000Default Solution treated + aged 538 °C / 4 h | The default aerospace balance of ~1400 MPa strength with good toughness and SCC resistance. | 1,345 | 1,413 | 14 | 45 HRC | — |
Solution treated + aged 510 °C / 4 h | Pick for maximum strength and hardness (fasteners, pins, tooling) where toughness demand is moderate. | 1,413 | 1,520 | 13 | 47 HRC | — |
What is 13-8Mo?
13-8Mo (UNS S13800, AMS 5629) is a martensitic precipitation-hardening stainless steel powder with a low-carbon, vacuum-melted chemistry that gives higher transverse toughness and cleanliness than 17-4PH at comparable hardness. In the default aged condition it provides 1345 MPa yield and 1413 MPa tensile strength with 14 % elongation at 45 HRC, and it is supplied for AM and wrought aerospace parts in Condition A plus the H950 to H1150M aging range. Maximum service temperature is about 425 °C. It costs more than 17-4PH and needs full solution treatment and re-aging after welding to restore strength in the HAZ. 13-8Mo has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 92% of steel grades. It melts at 1,400°C (2,552 °F). 13-8Mo has a yield strength of 1,345 MPa (195 ksi) and a tensile strength of 1,413 MPa (205 ksi) — stronger than 95% of steel grades. Elongation at break is 14% and the elastic modulus is 203 GPa (29.4 Msi).
What is 13-8Mo used for?
- aerospace structural parts
- fasteners
- landing gear components
Advantages
- Good corrosion resistance — 58/100, better than 99% of steel grades
- Polishes to a fine finish — 80/100, better than 97% of steel grades
- High strength — 1,345 MPa (195 ksi), better than 95% of steel grades
Limitations
- Low electrical conductivity — 1.7 % IACS, worse than 100% of steel grades
- Poor heat conductor — 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 99% of steel grades
- High embodied carbon — 5.4 kg CO₂/kg, worse than 97% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
13-8Mo properties
Typical room-temperature values for 13-8Mo-H1000; bars are the position among steel grades.
Physical3
13-8Mo has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 92% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
13-8Mo has a yield strength of 1,345 MPa (195 ksi) and a tensile strength of 1,413 MPa (205 ksi) — stronger than 95% of steel grades. Elongation at break is 14% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal6
13-8Mo is rated for continuous service to 425°C (797 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 99% of steel grades. Thermal expansion is 10.6 µm/m·K (5.89 µin/in·°F).
Electrical3
13-8Mo conducts electricity at 1.7 % IACS, worse than 100% of steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 99% of steel grades.
Sustainability4
Producing a kilogram of 13-8Mo takes about 80 MJ of energy and emits 5.4 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 30%.
Manufacturability8
13-8Mo's machinability is poor (25/100, worse than 93% of steel grades); weldability good (65/100); formability poor (30/100).
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 steel family
Yield strength against density for every steel grade FabDigit runs. 13-8Mo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 13-8Mo
Is 13-8Mo easy to machine?
Machine in Condition A or H1150 where possible; in H950–H1000 use rigid setups, positive-rake carbide, 20–40 m/min and heavy flood coolant to avoid work hardening and glazing.
Can 13-8Mo be welded?
Readily GTAW/EBW/laser welded autogenously or with matching filler; keep interpass low, then re-solution treat and re-age for full-strength joints (weld-as-aged loses strength in the HAZ).
Can 13-8Mo be formed, bent or molded?
Cold form only in Condition A with generous radii; heavy forming should be followed by re-solution treatment. Hot work 1150–950 °C, then solution anneal ~927 °C and air cool.
13-8Mo 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 | ≤ 0.05 | 0.03 |
| Mn | ≤ 0.2 | 0.05 |
| Si | ≤ 0.1 | 0.05 |
| P | ≤ 0.01 | |
| S | ≤ 0.01 | |
| Cr | 12.25 – 13.25 | 12.75 |
| Ni | 7.5 – 8.5 | 8 |
| Mo | 2 – 2.5 | 2.25 |
| Alprincipal precipitation hardener (NiAl) | 0.9 – 1.35 | 1.1 |
| N | ≤ 0.01 | |
| Fe | balance |
What surface finishes work on 13-8Mo?
Passivate per AMS 2700/ASTM A967 after machining; electropolishes and mirror-polishes well. Avoid electroplating without post-plate hydrogen bake (190 °C, 23 h) at H950–H1000 strength levels.
Surface treatments FabDigit runs on 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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 13-8Mo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S13800
- ASTM
- 5629
How much does 13-8Mo cost?
13-8Mo is a high-cost 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.
13-8Mo — frequently asked
What is 13-8Mo used for?
13-8Mo is typically used for aerospace structural parts, fasteners and landing gear components. In short: tougher than 17-4PH; aerospace PH stainless; tunable H950–H1150 strength.
What is the yield strength of 13-8Mo?
13-8Mo has a typical yield strength of 1,345 MPa (195 ksi) and a tensile strength of 1,413 MPa (205 ksi) — stronger than 95% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 13-8Mo easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine in Condition A or H1150 where possible; in H950–H1000 use rigid setups, positive-rake carbide, 20–40 m/min and heavy flood coolant to avoid work hardening and glazing.
Can 13-8Mo be welded?
Yes — weldability is rated good (65/100). Readily GTAW/EBW/laser welded autogenously or with matching filler; keep interpass low, then re-solution treat and re-age for full-strength joints (weld-as-aged loses strength in the HAZ).
What surface finishes work on 13-8Mo?
Passivate per AMS 2700/ASTM A967 after machining; electropolishes and mirror-polishes well. Avoid electroplating without post-plate hydrogen bake (190 °C, 23 h) at H950–H1000 strength levels.
Can 13-8Mo be formed, bent or molded?
Cold form only in Condition A with generous radii; heavy forming should be followed by re-solution treatment. Hot work 1150–950 °C, then solution anneal ~927 °C and air cool.
What is the maximum service temperature of 13-8Mo?
13-8Mo 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 13-8Mo-H1000 and 13-8Mo-H1150M?
H1000 is the default condition — the default aerospace balance of ~1400 MPa strength with good toughness and SCC resistance. H1150M: maximum ductility/toughness and lowest hardness; used for sour-service and heavy-section forgings. Yield strength is 1,345 MPa in H1000 versus 655 MPa in H1150M.
How much does 13-8Mo cost?
13-8Mo is a high-cost 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 5629 — Steel Bars, Forgings, Rings, 13Cr-8Ni-2.2Mo-1.1Al, consumable electrode melted — SAE International (2018)
- ASTM A564/A564M — Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars (UNS S13800) — ASTM International (2019)
- PH13-8Mo Stainless Steel Technical Data Sheet — Carpenter Technology / AK Steel (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- MMPDS-17 — Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
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.