Stainless Steel XM-9
UNS S36200
XM-9 (UNS S36200) is a precipitation-hardening stainless in the AM-350/355 and 17-7 PH performance class, supplied with a defined solution-plus-age heat treatment sequence for aerospace fastener and structural hardware.
Reference datasheet — XM-9 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 H900 condition
XM-9 tempers and conditions
XM-9 is supplied in 8 conditions, soft to hard. H900 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 |
|---|---|---|---|---|---|---|
Solution annealed | Pick for stock bar/wire that will be machined, cold-headed or formed before the customer's own ageing treatment. | 690 | 900 | 18 | 30 HRC | 2.2 % IACS |
Overaged 621 °C (1150 °F) for 4 h, maximum toughness | Pick as the most ductile, toughest and most SCC-tolerant aged condition, e.g. for sour or marine-adjacent service. | 795 | 930 | 18 | 30 HRC | — |
Condition A, cold drawn | Pick for cold-heading wire and straight, close-tolerance bar where a modest strength increase over Condition A is useful before ageing. | 860 | 1,000 | 13 | 33 HRC | — |
Aged 593 °C (1100 °F) for 4 h | Pick for over-aged parts needing good toughness and dimensional stability at moderate strength. | 930 | 1,000 | 16 | 33 HRC | — |
Solution treated and aged ~565 °C | Pick where improved toughness and chloride SCC resistance matter more than peak strength. | 1,000 | 1,070 | 15 | 35 HRC | — |
Solution treated and aged ~540 °C | Pick as the general-purpose balance of strength, ductility and stress-corrosion resistance. | 1,070 | 1,170 | 14 | 38 HRC | — |
Solution treated and aged ~510 °C | Pick when near-peak strength is wanted with slightly better ductility and toughness than H900. | 1,170 | 1,275 | 13 | 41 HRC | — |
H900Default Aged 482 °C (900 °F) for 1 h, peak hardness | Pick for maximum strength and hardness in fasteners and highly loaded fittings where notch toughness and chloride exposure are controlled. | 1,240 | 1,345 | 12 | 43 HRC | — |
What is XM-9?
XM-9 (UNS S36200) is a precipitation-hardening stainless in the AM-350/355 and 17-7 PH performance class, supplied with a defined solution-plus-age heat treatment sequence for aerospace fastener and structural hardware. In the default aged state it provides about 1240 MPa yield, 1345 MPa tensile, 12 % elongation and 43 HRC, with tempers from H900 through H1150 available to trade strength for toughness. Maximum service temperature is 315 °C, below AM-350 and Custom 455. Formability (score 20) and machinability (25) are low and corrosion resistance is moderate, so all forming and welding must precede ageing; 17-4 PH is the more widely stocked alternative. XM-9 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). XM-9 has a yield strength of 1,240 MPa (180 ksi) and a tensile strength of 1,345 MPa (195 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
What is XM-9 used for?
- Aerospace fasteners
- Structural hardware and fittings
- Cold-headed bolts and screws
- Pins and clevises
- Threaded rod ends
- Machined brackets and lugs
Advantages
- High strength — 1,240 MPa (180 ksi), better than 99% of stainless steel grades
Limitations
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 92% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
- Limited service temperature — 315°C (599 °F), worse than 85% of stainless steel grades
XM-9 properties
Typical room-temperature values for XM-9-H900; bars are the position among stainless steel grades.
Physical3
XM-9 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
XM-9 has a yield strength of 1,240 MPa (180 ksi) and a tensile strength of 1,345 MPa (195 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
XM-9 is rated for continuous service to 315°C (599 °F). It conducts heat at 16.3 W/m·K (9.42 BTU/hr·ft·°F), better than 68% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
XM-9 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of XM-9 takes about 55 MJ of energy and emits 4.7 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
XM-9's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability fair (45/100); formability poor (20/100).
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. XM-9 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with XM-9
Is XM-9 easy to machine?
Machine in Condition A with sharp, rigid, positive-rake carbide tooling, heavy feeds and flood coolant; finish-machine oversize if ageing follows, since H900 at ~43 HRC roughly halves tool life.
Can XM-9 be welded?
GTAW/GMAW/EBW with matching or 17-4 PH filler and low heat input; re-solution treat and re-age after welding to restore full properties, and avoid welding parts already in the aged condition.
Can XM-9 be formed, bent or molded?
Cold form, bend and cold-head only in the annealed condition with generous radii and interstage stress relief; all significant forming must precede the ageing cycle.
XM-9 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 |
|---|---|---|
| Clow carbon for soft martensite | ≤ 0.05 | 0.03 |
| Mn | ≤ 0.5 | 0.3 |
| Si | ≤ 0.5 | 0.3 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Crpassivity | 14 – 14.5 | 14.25 |
| Nicontrols Ms and martensite formation | 6.25 – 6.75 | 6.5 |
| TiNi3Ti precipitation strengthener | 0.65 – 0.9 | 0.8 |
| Fe | balance |
What surface finishes work on XM-9?
Passivate per ASTM A967 (nitric or citric) after machining; electropolishing and fine mechanical polishing give a bright, durable surface — no anodizing; bake after any plating to avoid hydrogen embrittlement at H900 strength.
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 XM-9 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S36200
How much does XM-9 cost?
XM-9 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.
XM-9 — frequently asked
What is XM-9 used for?
XM-9 is typically used for aerospace fasteners, structural hardware and fittings, cold-headed bolts and screws, pins and clevises, threaded rod ends and machined brackets and lugs. In short: aerospace fastener PH grade; high strength at 43 HRC; age-hardened after forming.
What is the yield strength of XM-9?
XM-9 has a typical yield strength of 1,240 MPa (180 ksi) and a tensile strength of 1,345 MPa (195 ksi) — stronger than 99% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is XM-9 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Machine in Condition A with sharp, rigid, positive-rake carbide tooling, heavy feeds and flood coolant; finish-machine oversize if ageing follows, since H900 at ~43 HRC roughly halves tool life.
Can XM-9 be welded?
With care — weldability is rated fair (45/100). GTAW/GMAW/EBW with matching or 17-4 PH filler and low heat input; re-solution treat and re-age after welding to restore full properties, and avoid welding parts already in the aged condition.
What surface finishes work on XM-9?
Passivate per ASTM A967 (nitric or citric) after machining; electropolishing and fine mechanical polishing give a bright, durable surface — no anodizing; bake after any plating to avoid hydrogen embrittlement at H900 strength.
Can XM-9 be formed, bent or molded?
Cold form, bend and cold-head only in the annealed condition with generous radii and interstage stress relief; all significant forming must precede the ageing cycle.
What is the maximum service temperature of XM-9?
XM-9 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 XM-9-H900 and XM-9-A?
H900 is the default condition — pick for maximum strength and hardness in fasteners and highly loaded fittings where notch toughness and chloride exposure are controlled. A: pick for stock bar/wire that will be machined, cold-headed or formed before the customer's own ageing treatment. Yield strength is 1,240 MPa in H900 versus 690 MPa in A.
How much does XM-9 cost?
XM-9 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
- ASTM A564/A564M — Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes — ASTM International (2019)
- ASTM A484/A484M — General Requirements for Stainless Steel Bars, Billets and Forgings — ASTM International (2020)
- SAE J1086 / UNS Metals & Alloys Numbering System — SAE International / ASTM (2017)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Specialty Handbook — Stainless Steels — ASM International (1994)
- Precipitation-hardening stainless bar product data (Almar 362 / S36200 class) — specialty stainless producers (2020)
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.