Stainless Steel S21900 CW-3/4H
Supply condition
UNS S21900 · AISI/SAE XM-10
CW-3/4H = cold worked, 3/4 hard
High-strength strip/wire temper where only mild bending is still needed.
Values for the CW-3/4H condition
Other S21900 tempers and conditions
S21900 is listed in 7 conditions; see the grade overview at S21900.
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 stocked condition for bar, plate, sheet and tube; best ductility, toughness and corrosion resistance. | 415 | 725 | 48 | 205 HB | — |
Hot worked / as-forged (not re-annealed) | Heavy forgings and hot-rolled bar supplied without final solution treatment; slightly higher strength, marginally lower corrosion resistance. | 450 | 760 | 40 | 17 HRC | 2.4 % IACS |
Cold drawn | Pick for straight, close-tolerance bar with a moderate strength bump over annealed and better chip control. | 620 | 860 | 25 | 22 HRC | 2.4 % IACS |
Cold worked, 1/4 hard | Modest cold reduction of strip/tube where extra yield strength is needed but forming is still required. | 690 | 930 | 25 | 25 HRC | 2.4 % IACS |
Cold worked, 1/2 hard | Mid-range strain-hardened temper for high-pressure tubing, springs and fasteners. | 860 | 1,035 | 18 | 31 HRC | 2.4 % IACS |
CW-3/4HThis page Cold worked, 3/4 hard | High-strength strip/wire temper where only mild bending is still needed. | 1,030 | 1,170 | 12 | 35 HRC | 2.4 % IACS |
Cold worked, full hard | Maximum strength strip/wire for springs and high-load flat parts; very limited formability. | 1,240 | 1,380 | 8 | 40 HRC | 2.4 % IACS |
What is S21900 CW-3/4H?
S21900 CW-3/4H is S21900 supplied in the CW-3/4H condition — high-strength strip/wire temper where only mild bending is still needed. S21900 CW-3/4H has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,170 MPa (170 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi). S21900 CW-3/4H has a density of 7.83 g/cm³ (0.283 lb/in³), heavier than 58% of stainless steel grades. It melts at 1,394°C (2,541 °F). Annealed is the default condition FabDigit quotes; CW-3/4H is available on request or by drawing note.
Advantages
- High strength — 1,030 MPa (149 ksi), better than 98% of stainless steel grades
Limitations
- Difficult to machine — 21/100, worse than 97% of stainless steel grades
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Poor heat conductor — 12.6 W/m·K (7.28 BTU/hr·ft·°F), worse than 88% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
S21900 CW-3/4H properties
Typical room-temperature values for S21900 CW-3/4H; 23 are specific to this condition. Other listed values are S21900 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S21900 CW-3/4H has a density of 7.83 g/cm³ (0.283 lb/in³), heavier than 58% of stainless steel grades. It melts at 1,394°C (2,541 °F).
Mechanical15
S21900 CW-3/4H has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,170 MPa (170 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S21900 CW-3/4H is rated for continuous service to 400°C (752 °F). It conducts heat at 12.6 W/m·K (7.28 BTU/hr·ft·°F), worse than 88% of stainless steel grades. Thermal expansion is 15.3 µm/m·K (8.5 µin/in·°F).
Electrical3
S21900 CW-3/4H conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (56/100), worse than 66% of stainless steel grades.
Sustainability4
Producing a kilogram of S21900 CW-3/4H takes about 53 MJ of energy and emits 5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
S21900 CW-3/4H's machinability is poor (21/100, worse than 97% of stainless steel grades); weldability good (60/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S21900 CW-3/4H
Is S21900 easy to machine?
Work-hardens rapidly: use rigid setups, positive-rake carbide, heavy feeds, low-to-moderate speeds and flood coolant; never dwell or rub.
Can S21900 be welded?
Readily welded by GTAW/GMAW/PAW with matching 21-6-9 filler or 209/240 type wire; no preheat, keep interpass low and avoid excessive heat input to preserve nitrogen and toughness.
Can S21900 be formed, bent or molded?
Cold formable but needs ~2× the press force of 304 and generous bend radii; hot work 1150–1200 °C and solution anneal ~1065 °C with rapid quench after forming.
What surface finishes work on S21900?
Passivate per ASTM A967 or electropolish after machining; anodizing is not applicable, and mechanical polishing must avoid smearing the work-hardened surface.
S21900 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 |
|---|---|---|
| CS21904 (XM-11) limits C to 0.04 max | ≤ 0.08 | 0.04 |
| Mn | 8 – 10 | 9 |
| Si | ≤ 1 | 0.4 |
| P | ≤ 0.06 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Cr | 19 – 21.5 | 20.5 |
| Ni | 5.5 – 7.5 | 6.5 |
| Nnitrogen is the principal strengthener | 0.15 – 0.4 | 0.3 |
| Fe | balance | — |
S21900 CW-3/4H — frequently asked
What is S21900 CW-3/4H used for?
S21900 CW-3/4H is typically used for cryogenic vessels, aerospace fasteners, marine hardware and pump components. In short: twice the yield of 304; cryogenic to 870 °C; nitronic 40 workhorse.
What is the yield strength of S21900 CW-3/4H?
S21900 CW-3/4H has a typical yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,170 MPa (170 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is S21900 CW-3/4H easy to machine?
Not especially — machinability is rated poor (21/100, worse than 97% of stainless steel grades). Work-hardens rapidly: use rigid setups, positive-rake carbide, heavy feeds, low-to-moderate speeds and flood coolant; never dwell or rub.
Can S21900 CW-3/4H be welded?
Yes — weldability is rated good (60/100). Readily welded by GTAW/GMAW/PAW with matching 21-6-9 filler or 209/240 type wire; no preheat, keep interpass low and avoid excessive heat input to preserve nitrogen and toughness.
What surface finishes work on S21900 CW-3/4H?
Passivate per ASTM A967 or electropolish after machining; anodizing is not applicable, and mechanical polishing must avoid smearing the work-hardened surface.
Can S21900 CW-3/4H be formed, bent or molded?
Cold formable but needs ~2× the press force of 304 and generous bend radii; hot work 1150–1200 °C and solution anneal ~1065 °C with rapid quench after forming.
What is the maximum service temperature of S21900 CW-3/4H?
S21900 CW-3/4H is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S21900 Annealed and S21900 CW-FH?
Annealed is the default condition — standard stocked condition for bar, plate, sheet and tube; best ductility, toughness and corrosion resistance. CW-FH: maximum strength strip/wire for springs and high-load flat parts; very limited formability. Yield strength is 415 MPa in Annealed versus 1,240 MPa in CW-FH.
Sources
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- AMS 5561 — Steel, Corrosion Resistant, Seamless Tubing 21Cr-6Ni-9Mn — SAE International (2018)
- AMS 5656 — Steel, Corrosion Resistant, Bars, Wire, Forgings 21Cr-6Ni-9Mn — SAE International (2016)
- Nitronic 40 (21-6-9) Stainless Steel Technical Data — ATI / AK Steel (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- MMPDS-17 austenitic stainless steel chapter — Battelle/FAA (2022)
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.