Special steel products
When the requirement says 'steel' but the duty says 'critical' — PH stainless, ultra-high-strength low-alloy, bearing and stabilised grades, manufactured and heat treated to specification.
Special Steels
Why specify this family
Special steels earn the name by doing one thing exceptionally: 17-4PH and 15-5PH pair stainless corrosion resistance with 1300 MPa strength from a single age; 300M and 4340 carry ultra-high-strength structural loads; 440C hardens to bearing-grade 58 HRC; 321 survives welded hot service that sensitises plain austenitics.
DMK Alloys manufactures products of special steels as bars, forged blanks and semi-finish machined components, with heat treatment and testing agreed per order.
Typical duty: landing-gear-class structures, shafts and gears, valve internals, bearings, exhaust and hot-air systems.
| Designation | Group | UNS | Datasheet |
|---|---|---|---|
| 17-4PH Stainless | Core grade — composition, properties, cross-references | S17400 | Full datasheet → |
| 15-5PH Stainless | Core grade — composition, properties, cross-references | S15500 | Full datasheet → |
| 300M Alloy Steel | Core grade — composition, properties, cross-references | K44220 | Full datasheet → |
| 4340 Alloy Steel | Core grade — composition, properties, cross-references | G43400 | Full datasheet → |
| 440C Stainless | Core grade — composition, properties, cross-references | S44004 | Full datasheet → |
| 321 Stainless | Core grade — composition, properties, cross-references | S32100 | Full datasheet → |
| 4130 | Aircraft-quality low-alloy steels | G41300 | Datasheet → |
| 4140 | Aircraft-quality low-alloy steels | G41400 | Datasheet → |
| 4330 Mod | Aircraft-quality low-alloy steels | — | Datasheet → |
| E4340 | Aircraft-quality low-alloy steels | G43406 | Datasheet → |
| 4620 | Aircraft-quality low-alloy steels | G46200 | Datasheet → |
| 52100 | Aircraft-quality low-alloy steels | G52986 | Datasheet → |
| 6150 | Aircraft-quality low-alloy steels | G61500 | Datasheet → |
| 8740 | Aircraft-quality low-alloy steels | G87400 | Datasheet → |
| 9310 | Aircraft-quality low-alloy steels | G93100 | Datasheet → |
| E9310 | Aircraft-quality low-alloy steels | G93106 | Datasheet → |
| 9Ni-4Co-0.30C | Aircraft-quality low-alloy steels | — | Datasheet → |
| D-6AC | Aircraft-quality low-alloy steels | — | Datasheet → |
| H-11 | Aircraft-quality low-alloy steels | T20811 | Datasheet → |
| HY-TUF | Aircraft-quality low-alloy steels | — | Datasheet → |
| Nitriding 135 Mod | Aircraft-quality low-alloy steels | — | Datasheet → |
| 15CDV6 | Aircraft-quality low-alloy steels | — | Datasheet → |
| 35NCD16 | Aircraft-quality low-alloy steels | — | Datasheet → |
| 25CrMo4 | Aircraft-quality low-alloy steels | — | Datasheet → |
| Aermet-type 100 | Ultra-high-strength & maraging | K92580 | Datasheet → |
| Maraging 250 | Ultra-high-strength & maraging | K92890 | Datasheet → |
| Maraging 300 | Ultra-high-strength & maraging | K93120 | Datasheet → |
| Maraging 350 | Ultra-high-strength & maraging | — | Datasheet → |
| 301 | Austenitic stainless (300 series) | S30100 | Datasheet → |
| 302 | Austenitic stainless (300 series) | S30200 | Datasheet → |
| 303 | Austenitic stainless (300 series) | S30300 | Datasheet → |
| 304 | Austenitic stainless (300 series) | S30400 | Datasheet → |
| 304L | Austenitic stainless (300 series) | S30403 | Datasheet → |
| 305 | Austenitic stainless (300 series) | S30500 | Datasheet → |
| 309 | Austenitic stainless (300 series) | S30900 | Datasheet → |
| 310 | Austenitic stainless (300 series) | S31000 | Datasheet → |
| 310S | Austenitic stainless (300 series) | S31008 | Datasheet → |
| 316 | Austenitic stainless (300 series) | S31600 | Datasheet → |
| 316L | Austenitic stainless (300 series) | S31603 | Datasheet → |
| 316Ti | Austenitic stainless (300 series) | S31635 | Datasheet → |
| 317 | Austenitic stainless (300 series) | S31700 | Datasheet → |
| 317L | Austenitic stainless (300 series) | S31703 | Datasheet → |
| 330 | Austenitic stainless (300 series) | N08330 | Datasheet → |
| 347 | Austenitic stainless (300 series) | S34700 | Datasheet → |
| 347H | Austenitic stainless (300 series) | S34709 | Datasheet → |
| 403 | Martensitic & ferritic stainless (400 series) | S40300 | Datasheet → |
| 405 | Martensitic & ferritic stainless (400 series) | S40500 | Datasheet → |
| 410 | Martensitic & ferritic stainless (400 series) | S41000 | Datasheet → |
| 410 Mod | Martensitic & ferritic stainless (400 series) | — | Datasheet → |
| 416 | Martensitic & ferritic stainless (400 series) | S41600 | Datasheet → |
| 416Se | Martensitic & ferritic stainless (400 series) | S41623 | Datasheet → |
| 420 | Martensitic & ferritic stainless (400 series) | S42000 | Datasheet → |
| 420F | Martensitic & ferritic stainless (400 series) | S42020 | Datasheet → |
| 422 | Martensitic & ferritic stainless (400 series) | S42200 | Datasheet → |
| 430 | Martensitic & ferritic stainless (400 series) | S43000 | Datasheet → |
| 430F | Martensitic & ferritic stainless (400 series) | S43020 | Datasheet → |
| 430FR | Martensitic & ferritic stainless (400 series) | — | Datasheet → |
| 431 | Martensitic & ferritic stainless (400 series) | S43100 | Datasheet → |
| 440A | Martensitic & ferritic stainless (400 series) | S44002 | Datasheet → |
| 440B | Martensitic & ferritic stainless (400 series) | S44003 | Datasheet → |
| 446 | Martensitic & ferritic stainless (400 series) | S44600 | Datasheet → |
| 13-8Mo | Precipitation-hardening & high-performance stainless | S13800 | Datasheet → |
| PH14-8Mo | Precipitation-hardening & high-performance stainless | S14800 | Datasheet → |
| 15-7Mo | Precipitation-hardening & high-performance stainless | S15700 | Datasheet → |
| 17-7PH | Precipitation-hardening & high-performance stainless | S17700 | Datasheet → |
| Alloy 455 | Precipitation-hardening & high-performance stainless | S45500 | Datasheet → |
| Alloy 465 | Precipitation-hardening & high-performance stainless | S46500 | Datasheet → |
| A-286 | Precipitation-hardening & high-performance stainless | S66286 | Datasheet → |
| AM 350 | Precipitation-hardening & high-performance stainless | S35000 | Datasheet → |
| AM 355 | Precipitation-hardening & high-performance stainless | S35500 | Datasheet → |
| Jethete M152 | Precipitation-hardening & high-performance stainless | — | Datasheet → |
| Greek Ascoloy | Precipitation-hardening & high-performance stainless | S41800 | Datasheet → |
| Nitronic-type 40 | Nitrogen-strengthened, duplex & super-austenitic | S21900 | Datasheet → |
| Nitronic-type 50 | Nitrogen-strengthened, duplex & super-austenitic | S20910 | Datasheet → |
| Nitronic-type 60 | Nitrogen-strengthened, duplex & super-austenitic | S21800 | Datasheet → |
| Duplex F51 | Nitrogen-strengthened, duplex & super-austenitic | S31803 | Datasheet → |
| Super Duplex F53 | Nitrogen-strengthened, duplex & super-austenitic | S32750 | Datasheet → |
| Super Duplex F55 | Nitrogen-strengthened, duplex & super-austenitic | S32760 | Datasheet → |
| 254SMO-type | Nitrogen-strengthened, duplex & super-austenitic | S31254 | Datasheet → |
| 904L | Nitrogen-strengthened, duplex & super-austenitic | N08904 | Datasheet → |
| S1 | British S-number airworthiness steels | — | Datasheet → |
| S14 | British S-number airworthiness steels | — | Datasheet → |
| S15 | British S-number airworthiness steels | — | Datasheet → |
| S21 | British S-number airworthiness steels | — | Datasheet → |
| S28 | British S-number airworthiness steels | — | Datasheet → |
| S61 | British S-number airworthiness steels | — | Datasheet → |
| S62 | British S-number airworthiness steels | — | Datasheet → |
| S80 | British S-number airworthiness steels | — | Datasheet → |
| S82 | British S-number airworthiness steels | — | Datasheet → |
| S92 | British S-number airworthiness steels | — | Datasheet → |
| S93 | British S-number airworthiness steels | — | Datasheet → |
| S97 | British S-number airworthiness steels | — | Datasheet → |
| S98 | British S-number airworthiness steels | — | Datasheet → |
| S99 | British S-number airworthiness steels | — | Datasheet → |
| S106 | British S-number airworthiness steels | — | Datasheet → |
| S120 | British S-number airworthiness steels | — | Datasheet → |
| S129 | British S-number airworthiness steels | — | Datasheet → |
| S130 | British S-number airworthiness steels | — | Datasheet → |
| S132 | British S-number airworthiness steels | — | Datasheet → |
| S134 | British S-number airworthiness steels | — | Datasheet → |
| S135 | British S-number airworthiness steels | — | Datasheet → |
| S140 | British S-number airworthiness steels | — | Datasheet → |
| S141 | British S-number airworthiness steels | — | Datasheet → |
| S142 | British S-number airworthiness steels | — | Datasheet → |
| S143 | British S-number airworthiness steels | — | Datasheet → |
| S144 | British S-number airworthiness steels | — | Datasheet → |
| S145 | British S-number airworthiness steels | — | Datasheet → |
| S150 | British S-number airworthiness steels | — | Datasheet → |
| S151 | British S-number airworthiness steels | — | Datasheet → |
| S154 | British S-number airworthiness steels | — | Datasheet → |
| S155 | British S-number airworthiness steels | — | Datasheet → |
| S157 | British S-number airworthiness steels | — | Datasheet → |
| S159 | British S-number airworthiness steels | — | Datasheet → |
| S162 | British S-number airworthiness steels | — | Datasheet → |
| S510 | British S-number airworthiness steels | — | Datasheet → |
| S511 | British S-number airworthiness steels | — | Datasheet → |
| S514 | British S-number airworthiness steels | — | Datasheet → |
| S515 | British S-number airworthiness steels | — | Datasheet → |
| S516 | British S-number airworthiness steels | — | Datasheet → |
| S518 | British S-number airworthiness steels | — | Datasheet → |
| S524 | British S-number airworthiness steels | — | Datasheet → |
| S526 | British S-number airworthiness steels | — | Datasheet → |
| S527 | British S-number airworthiness steels | — | Datasheet → |
| S534 | British S-number airworthiness steels | — | Datasheet → |
| S535 | British S-number airworthiness steels | — | Datasheet → |
Every designation links to its datasheet. Some designations correspond to trade names of their respective owners and are shown for identification only; availability, forms and dimensions are confirmed per enquiry.
Sourcing special steels?
Send grade, specification, form, dimensions and quantity to the export team for a manufacturer's quotation.