431 stainless steel is a martensitic stainless steel intended for heat treatment showing high mechanical properties and are martensitic, heat-treatable grades with excellent corrosion resistance, torque strength, high toughness and tensile properties, these properties make them ideal for bolt and shaft applications. These steels, however, cannot be cold-worked owing to their high yield strength, hence they are suitable for operations such as spinning, deep drawing, bending or cold heading , at the same time, very good corrosion resistance.In contrast to steels containing ~13% of ChromiumThis alloy has excellent corrosion resistance for a 400 series stainless and can be heat treated to high strength levels, most often supplied in the form of peeled bars, forged bars, hexagonal bars and even in the form of sheets, can sometimes amount to 45 HRC, X17CrNi16-2 / 1.4057, are delivered in heat treated condition +QT800 or +QT900. This grade is often used in the aerospace industry as fittings and boltings requiring high yield strength, used, among others, in the aerospace, marine, food, nitrogen, paper and food industries for particularly loaded parts of pumps, the production of screws, nuts, parts of valves of installations, shafts, sleeves or spindles, aircraft parts. The excellent corrosion resistance also lends itself well to the marine industry. Fabrication of martensitic steels is generally carried out using techniques that allow hardening and tempering treatments and poor weldability. The corrosion resistance properties of grade 431 steels are lower than that of austenitic grades. The operations of grade 431 are limited by their loss of strength at high temperatures, due to over-tempering, and loss of ductility at negative temperatures.
AOD
| Grade | Chemical Composition WT % | |||||||
|---|---|---|---|---|---|---|---|---|
| C | Mn | Si | P | S | Cr | Ni | ||
| 431, UNS S43100 | Max 0.20 | Max 1.00 | Max 1.00 | Max 0.040 | Max 0.030 | 15.0 - 17.0 | 1.25 - 2.5 | |
| 14Ch17N2, 14Х17Н2 | 0.11 - 0.17 | Max 0.8 | Max 0.8 | Max 0.030 | Max 0.025 | 16.0 - 18.0 | 1.5 - 2.5 | |
| 20Ch17N2, 20Х17Н2 | 0.17 - 0.25 | Max 0.8 | Max 0.8 | Max 0.035 | Max 0.025 | 16.0 - 18.0 | 1.5 - 2.5 | |
| X17CrNi16-2, 1.4057 | 0.12 - 0.22 | Max 1.5 | Max 1.0 | Max 0.040 | Max 0.030 | 15.0 - 17.0 | 1.5 - 2.5 | |
| LW 1.4044 | 0.12 - 0.20 | Max 1.0 | Max 1.0 | Max 0.035 | Max 0.025 | 15.0 - 18.0 | 2.0 - 3.0 | |
| X19CrNi17-2 | 0.14 - 0.23 | Max 1.0 | Max 1.0 | Max 0.040 | Max 0.015 | 15.5 - 17.5 | 1.5 - 2.5 | |
| AIR 9160 Z15CN17-03, Z 15 CN 17-03, Z15CN17.03 | 0.16 | - | - | - | - | 16.5 | 2.4 | |
| AF Z15CN16-02, Z 15 CN 16-02 | 0.15 - 0.20 | Max 1.0 | Max 1.0 | Max 0.040 | Max 0.025 | 15.5 - 17.0 | 1.5 - 2.5 | |
| Tempering Temperature (°C) | Tensile Strength (MPa) | Yield Strength 0.2% Proof (MPa) | Elongation (% in 50mm) | Hardness Brinell (HB) | Impact Charpy V (J) |
| Annealed * | 862 | 655 | 20 | 285 max | - |
| 204 | 1345 | 1055 | 20 | 388 | 50 |
| 316 | 1295 | 1035 | 19 | 375 | 53 |
| 427 | 1350 | 1080 | 19 | 388 | # |
| 538 | 1140 | 965 | 19 | 321 | # |
| 593 | 1015 | 770 | 20 | 293 | 64 |
| 650 | 960 | 695 | 20 | 277 | 84 |
| Grade | kg/m3 | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (μm/m/°C) | Thermal Conductivity (W/m.K) | °C (J/kg.K) | Electrical Resistivity (nΩ.m) | |||
|---|---|---|---|---|---|---|---|---|---|
| 0-100°C | 0-315°C | 0-538°C | at 100°C | at 500°C | |||||
| 431 | 7800 | 200 | 10.2 | 12.1 | - | 20.2 | - | 460 | 720 |
Full anneal — Full annealing cannot be performed on 431, UNS S43100, S80, X17CrNi16-2, 1.4057 martensitic stainless steel. This grade gets hardened even during slow cooling.
Process anneal — 431, UNS S43100, S80, X17CrNi16-2, 1.4057 martensitic stainless steel are heated to 620 to 660°C and then air-cooled.
431, UNS S43100, S80, X17CrNi16-2, 1.4057 martensitic stainless steel are generally hardened by heating at temperatures from 980 to 1065°C, holding for nearly ½ h, followed by oil or air quenching. Complex or hardened parts of grade 431 steels can be pre-heated to temperatures from 760 to 790°C and tempered, to improve their mechanical properties. Tempering of these steels at 425 to 600°C should be avoided, owing to the loss of impact toughness at this temperature range.
Welding of 431, UNS S43100, S80, X17CrNi16-2, 1.4057 martensitic stainless steel is difficult due to the chances of cracking. It is recommended to pre-heat the materials to 200 - 300°C before welding, and carry out post-weld heat treatment at 650°C. Welding can be performed using grade 410 filler rods, but ductile welds can be achieved using grades 308L, 309 or 310 steels.
431, UNS S43100, S80, X17CrNi16-2, 1.4057 martensitic stainless steel can be easily machined in their annealed state. However, it is extremely difficult to machine these steels if they are hardened above 30HRC.
Steel grade
Special steel