Stainless Steel XM-15 3/4H
Supply condition
UNS S38100
3/4H = three-quarter hard
Near-maximum strength strip for flat springs and clips with minimal forming.
Values for the 3/4H condition
Other XM-15 tempers and conditions
XM-15 is listed in 7 conditions; see the grade overview at XM-15.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed (~1040–1120 °C, water quenched) | Standard stock condition for plate, sheet, bar and tube; maximum corrosion resistance and ductility. | 260 | 590 | 52 | 160 HB | — |
Hot rolled | Lowest-cost heavy sections for later machining; must be solution annealed before corrosive service. | 290 | 600 | 45 | 180 HB | 2 % IACS |
Cold drawn | Pick for straight, close-tolerance bar with higher yield strength and better machining chip control than annealed. | 450 | 690 | 32 | 16 HRC | 2 % IACS |
Quarter hard | Light cold work for springy sheet parts that still need appreciable bend ductility. | 520 | 760 | 25 | 22 HRC | 2 % IACS |
Half hard | Use where higher strength flat stock is needed and forming is limited to gentle bends. | 690 | 900 | 15 | 28 HRC | 2 % IACS |
3/4HThis page Three-quarter hard | Near-maximum strength strip for flat springs and clips with minimal forming. | 830 | 1,010 | 10 | 32 HRC | 2 % IACS |
Full hard | Maximum as-rolled strength for spring wire and shims; essentially no forming capability. | 930 | 1,100 | 7 | 35 HRC | 2 % IACS |
What is XM-15 3/4H?
XM-15 3/4H is XM-15 supplied in the 3/4H condition — near-maximum strength strip for flat springs and clips with minimal forming. XM-15 3/4H has a yield strength of 830 MPa (120 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 97% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 196 GPa (28.4 Msi). XM-15 3/4H has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,370°C (2,498 °F). Annealed is the default condition FabDigit quotes; 3/4H is available on request or by drawing note.
Advantages
- High strength — 830 MPa (120 ksi), better than 97% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- Limited ductility — 10%, worse than 98% of stainless steel grades
- Limited service temperature — 370°C (698 °F), worse than 84% of stainless steel grades
- High embodied carbon — 5.6 kg CO₂/kg, worse than 83% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
- Low electrical conductivity — 2 % IACS, worse than 77% of stainless steel grades
XM-15 3/4H properties
Typical room-temperature values for XM-15 3/4H; 22 are specific to this condition. Other listed values are XM-15 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
XM-15 3/4H has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical14
XM-15 3/4H has a yield strength of 830 MPa (120 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 97% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
XM-15 3/4H is rated for continuous service to 370°C (698 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
XM-15 3/4H conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of XM-15 3/4H takes about 58 MJ of energy and emits 5.6 kg of CO₂ — more than 66% of stainless steel grades. Typical recycled content is 55%.
Manufacturability8
XM-15 3/4H's machinability is poor (34/100, worse than 55% of stainless steel grades); weldability good (65/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with XM-15 3/4H
Is XM-15 easy to machine?
Gummy and work-hardening like 304 but more abrasive due to 2% Si — use rigid setups, positive-rake carbide, heavy constant feed, no dwelling, and flood coolant.
Can XM-15 be welded?
Weldable by GTAW/GMAW/SMAW with 308/309-type or matching high-Si filler; low heat input, no preheat, and normally no post-weld anneal since the grade resists sensitization.
Can XM-15 be formed, bent or molded?
Good cold formability with a lower work-hardening rate than 301/304 thanks to 18% Ni; allow generous bend radii in hard tempers and interstage anneal at 1040–1120 °C followed by rapid cooling.
What surface finishes work on XM-15?
Pickle and passivate (ASTM A967 nitric or citric) after fabrication; the Si-rich scale from hot work needs aggressive pickling or abrasive removal, and the alloy polishes and electropolishes well.
XM-15 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 | ≤ 0.08 | 0.04 |
| Mn | ≤ 2 | 1.2 |
| Sikey addition for oxidizing-acid and oxidation resistance | 1.5 – 2.5 | 2 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 17 – 19 | 18 |
| Ni | 17.5 – 18.5 | 18 |
| Fe | balance | — |
XM-15 3/4H — frequently asked
What is XM-15 3/4H used for?
XM-15 3/4H is typically used for nitric acid plant equipment, chemical process vessels, acid piping and fittings, heat exchanger tubing, welded tanks for oxidizing acids and furnace and heat-resisting fixtures. In short: sensitization-resistant nitric acid grade; silicon-bearing 18Cr-18Ni austenitic; lower work-hardening than 304.
What is the yield strength of XM-15 3/4H?
XM-15 3/4H has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 97% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is XM-15 3/4H easy to machine?
Not especially — machinability is rated poor (34/100, worse than 55% of stainless steel grades). Gummy and work-hardening like 304 but more abrasive due to 2% Si — use rigid setups, positive-rake carbide, heavy constant feed, no dwelling, and flood coolant.
Can XM-15 3/4H be welded?
Yes — weldability is rated good (65/100). Weldable by GTAW/GMAW/SMAW with 308/309-type or matching high-Si filler; low heat input, no preheat, and normally no post-weld anneal since the grade resists sensitization.
What surface finishes work on XM-15 3/4H?
Pickle and passivate (ASTM A967 nitric or citric) after fabrication; the Si-rich scale from hot work needs aggressive pickling or abrasive removal, and the alloy polishes and electropolishes well.
Can XM-15 3/4H be formed, bent or molded?
Good cold formability with a lower work-hardening rate than 301/304 thanks to 18% Ni; allow generous bend radii in hard tempers and interstage anneal at 1040–1120 °C followed by rapid cooling.
What is the maximum service temperature of XM-15 3/4H?
XM-15 3/4H is rated for continuous use to about 370°C (698 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between XM-15 Annealed and XM-15-FH?
Annealed is the default condition — standard stock condition for plate, sheet, bar and tube; maximum corrosion resistance and ductility. FH: maximum as-rolled strength for spring wire and shims; essentially no forming capability. Yield strength is 260 MPa in Annealed versus 930 MPa in FH.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- SAE/ASTM DS-56 Metals & Alloys in the Unified Numbering System (UNS S38100) — SAE International / ASTM (2017)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.