Alleima® 4C54 is a ferritic, heat resisting, stainless chromium steel, characterized by:
- Extremely good resistance to reducing sulphurous gases
- Very good resistance to oxidation in air
- Good resistance to oil-ash corrosion
- Good resistance to molten copper, lead and tin
This steel can be used at temperatures up to 1100°C (2010°F). However, allowance should be made for the low creep strength at the highest temperatures in order to avoid distortion due to the mass of the steel.
Standards
- ASTM: 446-1
- UNS: S44600
- EN Number: 1.4749
Certificates
Status according to EN 10 204 3.1
Chemical composition (nominal) %
| C | Si | Mn | P | S | Cr | N |
|---|---|---|---|---|---|---|
| ≤0.20 | 0.5 | 0.8 | ≤0.030 | ≤0.015 | 26.5 | 0.2 |
Forms of supply
Sizes and tolerances
Round-cornered square, as well as round billets, are produced in a wide range of sizes according to the following tables. Larger sizes offered on request.
Surface conditions
Square billets
Unground, spot ground or fully ground condition.
Round billets
Peel turned or black condition.
| Size | Tolerance | Length |
|---|---|---|
| mm | mm | m |
| 80 | +/-2 | 4 - 6.3 |
| 100, 114, 126, 140, 150 | +/-3 | 4 - 6.3 |
| 160, 180, 195, 200 | +/-4 | 4 - 6.3 |
| >200 - 350 | +/-5 | 3 - 5.3 |
Sizes and tolerances apply to the rolled/forged condition.
| Size | Tolerance | Length |
|---|---|---|
| mm | mm | m |
| 75 - 200 (5 mm interval) | +/-1 | max 10 |
| >200 - 450 | +/-3 | 3 - 8 |
| Size | Tolerance | Length |
|---|---|---|
| mm | mm | m |
| 77 - 112 (5 mm interval) | +/-2 | max 10 |
| 124, 134 | +/-2 | max 10 |
| 127, 147, 157 | +/-2 | max 10 |
| 142, 152, 163 | +/-2 | max 10 |
| 168, 178, 188 | +/-2 | max 10 |
| 183, 193 | +/-2 | max 10 |
Other products
- Hollow bar
Mechanical properties
At 20°C (68°F)
| Proof strength | Tensile strength | Elong. | Hardness | ||
|---|---|---|---|---|---|
| Rp0.21) | Rp1.01) | Rm | A2) | A2" | Vickers. |
| MPa | MPa | MPa | % | % | |
| approx. | |||||
| ≥275 | ≥320 | 500-700 | ≥20 | ≥18 | 190 |
| Proof strength | Tensile strength | Elong. | Hardness | ||
|---|---|---|---|---|---|
| Rp0.21) | Rp1.01) | Rm | A2) | A2" | Vickers. |
| MPa | MPa | MPa | % | % | |
| approx. | |||||
| ≥40 | ≥46 | 73-102 | ≥20 | ≥18 | 190 |
1 MPa = 1 N/mm2
1) Rp0.2 and Rp1.0 correspond to 0.2% offset and 1.0% offset yield strength, respectively.
2) Based on L0 = 5.65 √S0, where L0 is the original gauge length and S0 the original cross-sectional area.
At high temperatures
| Temperature | Proof strength | Tensile strength | Creep-rupture strength | ||
|---|---|---|---|---|---|
| Rp0.21) | Rp1.01) | 10 000 h | 100 000 h | ||
| oC | MPa | MPa | Rm | MPa | MPa |
| min. | min. | MPa | approx. | approx. | |
| 100 | 235 | 280 | 450 | ||
| 200 | 215 | 260 | 430 | ||
| 300 | 200 | 250 | 430 | ||
| 400 | 185 | 245 | 430 | ||
| 500 | 175 | 240 | 375 | 100 | 55 |
| 525 | 165 | 230 | 335 | 77 | 43 |
| 550 | 150 | 200 | 290 | 59 | 33 |
| 575 | 46 | 26 | |||
| 600 | 35 | 20 | |||
| 625 | 25 | 14 | |||
| 650 | 18 | 10 | |||
| 675 | 13 | 7.0 | |||
| 700 | 9.5 | 5.0 | |||
| 725 | 7.6 | 4.0 | |||
| 750 | 6.2 | 3.3 | |||
| 775 | 5.0 | 2.7 | |||
| 800 | 4.3 | 2.3 | |||
| 825 | 3.4 | 1.9 | |||
| 850 | 2.8 | 1.5 | |||
| 875 | 2.3 | 1.2 | |||
| 900 | 1.9 | 1.0 | |||
| Temperature | Proof strength | Tensile strength | Creep-rupture strength | ||
|---|---|---|---|---|---|
| Rp0.21) | Rp1.01) | Rm | 10 000 h | 100 000 h | |
| oC | ksi | ksi | ksi | ksi | ksi |
| min. | min. | approx. | approx. | ||
| 200 | 34.4 | 40.9 | 66.7 | ||
| 400 | 31.0 | 37.7 | 62.3 | ||
| 600 | 28.7 | 36.1 | 62.3 | ||
| 800 | 26.8 | 35.5 | 62.2 | ||
| 1000 | 22.9 | 31.9 | 46.0 | 9.7 | 5.5 |
| 1050 | 7.3 | 4.1 | |||
| 1100 | 5.5 | 3.0 | |||
| 1150 | 3.9 | 2.2 | |||
| 1200 | 2.6 | 1.5 | |||
| 1250 | 1.9 | 1.01 | |||
| 1300 | 1.35 | 0.71 | |||
| 1350 | 1.04 | 0.58 | |||
| 1400 | 0.83 | 0.46 | |||
| 1450 | 0.67 | 0.38 | |||
| 1500 | 0.54 | 0.33 | |||
| 1550 | 0.43 | 0.28 | |||
| 1600 | 0.36 | 0.20 | |||
| 1650 | 0.28 | 0.16 | |||
| 1700 | 0.26 | 0.14 | |||
Since Alleima® 4C54 has very large creep-rupture elongation, often more than 100%, and little resistance to creep, it is necessary to allow for considerable creep deformation long before rupture occurs. At normal service temperatures, i.e. over 700 °C (1290 °F), even the dead weight of the tubes can cause stresses leading to large deformations.
Careful attention must therefore be given to the way in which the tubes are supported. Alleima® 4C54, in common with other ferritic chromium steels, are less tough than austenitic stainless steels in the as-delivered condition. The transition temperature of Alleima® 4C54 is around 100-150 °C (210-300 °F). After a period of operation, toughness at room temperature can decrease further. For this reason, large impact stresses and the like should be avoided during repairs.
The graph in figure 1 can be used to determine the temperature above which design calculations should be based on creep-rupture strength rather than proof strength.
Figure 1. 0.2% proof strength and creep-rupture stress at 10 000h and 100 000h.
Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.