Stainless Steel PH 13-8 Mo
UNS S13800 · AISI/SAE PH13-8Mo, XM-13 · ASTM A564, A564 Type XM-13 · EN 1.4534
Martensitic precipitation-hardening stainless with molybdenum addition, providing high strength (up to ~1500MPa) with good fracture toughness and stress-corrosion resistance for aerospace fasteners and structural parts.
Values for the Condition A condition
PH 13-8 Mo tempers and conditions
PH 13-8 Mo is supplied in 8 conditions, soft to hard. Condition A is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Double overaged 760 °C + 621 °C | Use the 760 °C/2 h + 621 °C/4 h double age when maximum toughness and stress-corrosion cracking resistance in marine or hydrogen service outweigh the drop to 655 MPa yield. | 655 | 895 | 20 | 28 HRC | — |
Condition ADefault solution annealed (~830 °C, air/oil cooled) | Pick the solution annealed stock (~830 °C, air or oil cooled) for rough machining, forming and welding, then apply a single ageing treatment to reach final strength. | 800 | 1,000 | 14 | 33 HRC | — |
Overaged 621 °C (1150 °F) for 4 h, maximum toughness | Pick the softest single-step age (4 h at 621 °C / 1150 °F) for corrosive or hydrogen environments: 965 MPa yield with 18% elongation and the best toughness and SCC resistance. | 965 | 1,070 | 18 | 33 HRC | — |
Aged 593 °C (1100 °F) for 4 h | Age 4 h at 593 °C (1100 °F) and air cool for thick sections that need high fracture toughness; yield drops to 1105 MPa but elongation reaches 16% and service temperature rises to 480 °C. | 1,105 | 1,210 | 16 | 37 HRC | — |
Aged 4 h at 566 °C (1050 °F), air cooled | Choose the 4 h age at 566 °C (1050 °F), air cooled, when 1240 MPa yield must be combined with good stress-corrosion resistance for high-strength parts in corrosive service. | 1,240 | 1,330 | 15 | 42 HRC | — |
Aged 552 °C (1025 °F) for 4 h | Pick ageing 4 h at 552 °C when slightly lower strength of 1310 MPa yield buys better ductility and improved resistance to stress-corrosion cracking. | 1,310 | 1,410 | 14 | 43 HRC | — |
Aged 4 h at 540 °C (1000 °F), air cooled | Use ageing 4 h at 540 °C as the common strength-toughness compromise at 1380 MPa yield; this is the most typical delivered aged state for aerospace structural parts. | 1,380 | 1,480 | 13 | 45 HRC | 14 W/m·K |
Aged 4 h at 510 °C (950 °F), air cooled | Choose ageing 4 h at 510 °C for the highest strength and hardness, as in landing-gear pins and high-strength fasteners, accepting the lowest toughness and SCC resistance. | 1,480 | 1,590 | 12 | 47 HRC | — |
What is PH 13-8 Mo?
Martensitic precipitation-hardening stainless with molybdenum addition, providing high strength (up to ~1500MPa) with good fracture toughness and stress-corrosion resistance for aerospace fasteners and structural parts. PH 13-8 Mo has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 58% of stainless steel grades. It melts at 1,400°C (2,552 °F). PH 13-8 Mo has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 96% of stainless steel grades. Elongation at break is 14% and the elastic modulus is 203 GPa (29.4 Msi).
What is PH 13-8 Mo used for?
- Aerospace landing gear components
- High-strength aerospace fasteners
- Airframe structural fittings
- Shafts and actuator rods
- Valve and pump components
- Nuclear and petrochemical hardware
- Tooling and die inserts
Advantages
- High strength — 800 MPa (116 ksi), better than 96% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- Limited ductility — 14%, worse than 91% of stainless steel grades
- Limited service temperature — 315°C (599 °F), worse than 85% of stainless steel grades
PH 13-8 Mo properties
Typical room-temperature values for PH 13-8 Mo-Condition A; bars are the position among stainless steel grades.
Physical3
PH 13-8 Mo has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 58% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
PH 13-8 Mo has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 96% of stainless steel grades. Elongation at break is 14% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal5
PH 13-8 Mo is rated for continuous service to 315°C (599 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 80% of stainless steel grades. Thermal expansion is 10.6 µm/m·K (5.89 µin/in·°F).
Electrical3
PH 13-8 Mo conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of PH 13-8 Mo takes about 62 MJ of energy and emits 4.8 kg of CO₂ — more than 75% of stainless steel grades. Typical recycled content is 30%.
Manufacturability7
PH 13-8 Mo's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability good (60/100); formability fair (40/100).
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. PH 13-8 Mo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PH 13-8 Mo
Is PH 13-8 Mo easy to machine?
Roughing is easiest in Condition A or the H1150 temper; aged tempers (H950–H1025) need rigid machines, low speed with steady heavier feed, sharp coated carbide and ample coolant. Expect cutting rates around 20–30 % of AISI 1212.
Can PH 13-8 Mo be welded?
GTAW and EBW weldability is good, usually autogenous or with matching filler. Weld in Condition A and re-solution treat plus age the whole part to restore strength; keep heat input low to limit delta ferrite and softened zones.
Can PH 13-8 Mo be formed, bent or molded?
Only limited cold forming in Condition A, with large springback and a low n-value. Hot form complex shapes and re-solution treat afterwards; aged material is effectively non-formable.
Manufacturability
The process limits FabDigit applies to PH 13-8 Mo. Every PH 13-8 Mo part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair32 / 100 |
|---|---|
| ISO material group | M.3 |
| Cutting speed (rough / finish) | 120 / 140 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair40 / 100 |
|---|---|
| Weldability | Better60 / 100 |
PH 13-8 Mo 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 | 0.01 |
| Slow sulfur to ensure transverse toughness | ≤ 0.01 | 0 |
| Cr | 12.25 – 13.25 | 12.7 |
| Ni | 7.5 – 8.5 | 8 |
| Mo | 2 – 2.5 | 2.25 |
| Alforms NiAl strengthening phase | 0.9 – 1.35 | 1.1 |
| N | ≤ 0.01 | 0.01 |
| Fe | balance |
What surface finishes work on PH 13-8 Mo?
Polishes to a mirror finish because of the clean VIM melting practice. Passivation is the standard protection; chrome or cadmium plating is possible but requires a 190 °C hydrogen bake after plating to avoid embrittlement.
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).
Plating
Organic Coating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel PH 13-8 Mo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S13800
- AISI / SAE
- PH13-8MoXM-13
- ASTM
- A564A564 Type XM-13
- EN / DIN / Werkstoff-Nr.
- 1.4534
How much does PH 13-8 Mo cost?
PH 13-8 Mo is a premium-cost stainless steel ($$$), cheaper than about 51% 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.
PH 13-8 Mo — frequently asked
What is PH 13-8 Mo used for?
PH 13-8 Mo is typically used for aerospace landing gear components, high-strength aerospace fasteners, airframe structural fittings, shafts and actuator rods, valve and pump components and nuclear and petrochemical hardware. In short: aerospace high-strength PH.
What is the yield strength of PH 13-8 Mo?
PH 13-8 Mo has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 96% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is PH 13-8 Mo easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Roughing is easiest in Condition A or the H1150 temper; aged tempers (H950–H1025) need rigid machines, low speed with steady heavier feed, sharp coated carbide and ample coolant. Expect cutting rates around 20–30 % of AISI 1212.
Can PH 13-8 Mo be welded?
Yes — weldability is rated good (60/100). GTAW and EBW weldability is good, usually autogenous or with matching filler. Weld in Condition A and re-solution treat plus age the whole part to restore strength; keep heat input low to limit delta ferrite and softened zones.
What surface finishes work on PH 13-8 Mo?
Polishes to a mirror finish because of the clean VIM melting practice. Passivation is the standard protection; chrome or cadmium plating is possible but requires a 190 °C hydrogen bake after plating to avoid embrittlement.
Can PH 13-8 Mo be formed, bent or molded?
Only limited cold forming in Condition A, with large springback and a low n-value. Hot form complex shapes and re-solution treat afterwards; aged material is effectively non-formable.
What is the maximum service temperature of PH 13-8 Mo?
PH 13-8 Mo is rated for continuous use to about 315°C (599 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between PH 13-8 Mo Condition A and PH 13-8 Mo-H950?
Condition A is the default condition — pick the solution annealed stock (~830 °C, air or oil cooled) for rough machining, forming and welding, then apply a single ageing treatment to reach final strength. H950: choose ageing 4 h at 510 °C for the highest strength and hardness, as in landing-gear pins and high-strength fasteners, accepting the lowest toughness and SCC resistance. Yield strength is 800 MPa in Condition A versus 1,480 MPa in H950.
How much does PH 13-8 Mo cost?
PH 13-8 Mo is a premium-cost stainless steel ($$$), cheaper than about 51% 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.
Can FabDigit make parts in PH 13-8 Mo?
Yes — PH 13-8 Mo is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A564/A564M — Type XM-13 (UNS S13800) — ASTM (2019)
- AMS 5629 — Steel Bars, Forgings, 13Cr-8.0Ni-2.2Mo-1.1Al, Premium Quality — SAE International (2018)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- MMPDS — Metallic Materials Properties Development and Standardization (PH13-8Mo) — Battelle/FAA (2023)
- PH13-8Mo / Custom 465-class PH stainless technical data — Carpenter Technology / AK Steel (2021)
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.