AISI 503 | EN 1.7386 | DIN X11CrMo9-1 is a special martensitic «*stainless steel», which is also commonly called chromium steel. It is designed for primary forming of deformed products. It has very low thermal conductivity among deformed alloy steels.
High-alloy boiler steel for operation at elevated temperatures is supplied in the form of pipes, flanges, rods and forgings with a chromium content of 9% and molybdenum of 1%. The material has a martensitic structure after tempering and a ferritic structure in the annealed condition, is characterized by high resistance to creep/oxidation and cracks, and low thermal expansion.
The steel is intended for operation at temperatures of 550 °C - 650 °C for power engineering and petrochemical industries for pipelines, secondary and branch superheaters, steam and branch manifolds, turbine parts, flanges, connectors, heat exchangers. When choosing this steel for a specific application, it is necessary to take into account its characteristics and operating conditions.
Heat treatment
- Softening annealing at 950 °C - 980 °C.
- Nitriding at 890 °C - 950 °C.
- Hardening at 720 °C - 800 °C.
Physical properties
- Density of steel (weight) = 7.79 g/cm3.
- Magnetic properties: magnetic.
Mechanical properties
| Yield strength, min., ReH, MPa | 210 | |
| Tensile strength (tensile strength), min., Rm, MPa | 460 - 640 | |
| Relative elongation, min., % | Longitudinal samples | 20 |
| Transverse samples | 18 | |
| Impact work KV at 20°C, min., J | Longitudinal samples | 40 |
| Transverse samples | 27 | |
| Yield strength at 100 °C, ReH (MPa) | 187 | |
| Yield strength at 150 °C, ReH (MPa) | 186 | |
| Yield strength at 200 °C, ReH (MPa) | 178 | |
| Yield strength at 250 °C, ReH (MPa) | 177 | |
| Yield strength at 300 °C, ReH (MPa) | 175 | |
| Yield strength at 350 °C, ReH (MPa) | 171 | |
| Yield strength at 400 °C, ReH (MPa) | 164 | |
| Yield strength at 450 °C, ReH (MPa) | 153 | |
| Yield strength at 500 °C, ReH (MPa) | 142 | |
| Yield strength at 550 °C, ReH (MPa) | 120 | |
Chemical composition of steel grade AISI 503 | EN 1.7386 | DIN X11CrMo9-1 | |||||||||
| C | Si | Mn | P | S | Cr | Mo | Al | Cu | Fe |
| 0,08-0,15 | 0,25-1,00 | 0,3-0,6 | <0,025 | <0,01 | 8,0-10,0 | 0,9-1,1 | <0,04 | <0,3 | Other |
*Stainless steel is a steel that is resistant to corrosion in the atmosphere and aggressive environments and contains at least 10.5% chromium.
Stainless Steel Round Pipe 
Stainless Steel Square Pipe 
Stainless Steel Rectangular Pipe 
Stainless Steel Oval Pipe 
Stainless Steel Elbow 
Stainless Steel Decorative Cover 
Stainless Steel Flange 
Stainless Steel Plug 
Stainless Steel Handrail Holder