2022-10-26 14:13
(supersedes all previous editions)
Sanicro® 25 is an austenitic 22Cr25NiWCoCu stainless steel material with excellent high temperature properties, designed for use in advanced pulverized coal fired steam boilers. The grade is characterized by:
Product standards
Seamless tube and pipe: ASTM A213, ASTM A312
Approvals
C | Si | Mn | P | S | Cr | Ni | W | Co | Cu | Nb | N |
---|---|---|---|---|---|---|---|---|---|---|---|
≤0.1 | 0.2 | 0.5 | ≤0.025 | ≤0.015 | 22.5 | 25 | 3.6 | 1.5 | 3.0 | 0.5 | 0.23 |
The high creep strength of Sanicro® 25 combined with its good corrosion resistance makes it an extremely suitable option for use in superheaters and reheaters in advanced coal fired power boilers. Use in high temperature applications in other types of steam boilers employing different fuel types is also possible. The material has been specifically developed for use at material temperatures up to around 700°C (1300oF).
Sanicro® 25 has very good resistance to hot corrosion in a coal ash environment.
Oxidation tests in air, performed as both isothermal tests at 650°C (1202oF) and 750°C (1382oF) for 1000, 2000 and 3000 hours and discontinuous tests with cooling to room temperature after 24, 50, 100, 200, 500, 1000, 1500, 2000 and 3000 hours, show a very low mass rate change.
Oxidation tests in aqueous steam at 600°C (1112oF) and 700°C (1292oF) for 500 and 1000 hours respectively, showed that Sanicro® 25 has very good oxidation resistance.
The material can be bent at high as well as at low temperatures.
Recommended temperature range for hot bending is 850-1250°C (1560-2280°F) . Following hot bending, solution annealing is needed, unless the bending has been performed at controlled temperatures between 1180°C and 1250°C (2155°F and 2280°F).
Cold-bending should be followed by solution annealing if the cold deformation is >20% or the R/D ratio is ≤2.5, if the service temperature is in the creep range. For best corrosion properties at high temperatures it is recommended that solution annealing should be performed, even at lower degrees of cold forming.
See also the Heat treatment section.
Sanicro® 25 is supplied as cold pilgered solution annealed and white-pickled seamless tubes, in common reheater and superheater boiler tube dimensions.
The VdTÜV-material datasheet 555, 23.10.2018, applies for outside diameter 25 mm to 114.3 mm and wall thickness 4.5 mm -12.5 mm.
Tubes are delivered in the heat treated condition. If additional heat treatment is needed due to further processing, the following is recommended.
1180-1250°C (2155-2280°F) and quenched.
Contact Alleima for advice regarding further heat treatment issues.
Proof strength | Tensile strength | Elong. | Hardness Vickers | ||
---|---|---|---|---|---|
Rp0.2a | Rp1.0a | Rm | Ab | A2" | |
MPa | MPa | MPa | % | % | |
approx. | |||||
≥310 | ≥355 | ≥680 | ≥40 | ≥40 | 185 |
1 MPa = 1 N/mm2
Proof strength | Tensile strength | Elong. | Hardness Vickers | ||
---|---|---|---|---|---|
Rp0.2a | Rp1.0a | Rm | Ab | A2" | |
ksi | ksi | ksi | % | % | |
approx. | |||||
≥45.0 | ≥50.0 | ≥99.0 | ≥40 | ≥40 | 185 |
a) Rp0.2 and Rp1.0 correspond to 0.2% offset and 1.0% offset yield strength, respectively.
b) Based on L0 = 5.65 √S0, where L0 is the original gauge length and S0 is the original cross-section area.
Temperature | Proof strength | Tensile strength | |
---|---|---|---|
Rp0.2 | Rp1.0 | Rm | |
°C | MPa | MPa | MPa |
min | min | min | |
100 | 250 | 315 | 625 |
200 | 225 | 255 | 575 |
300 | 210 | 240 | 560 |
400 | 200 | 225 | 550 |
500 | 195 | 215 | 535 |
600 | 180 | 205 | 500 |
700 | 180 | 195 | 455 |
800
|
180
|
195
|
355
|
Temperature | Proof strength | Tensile strength | |
---|---|---|---|
Rp0.2 | Rp1.0 | Rm | |
°F | ksi | ksi | ksi |
min | min | min | |
200 | 38.6 | 45.0 | 91.1 |
400 | 33.0 | 38.0 | 84.1 |
600 | 29.7 | 33.9 | 80.9 |
800 | 28.1 | 31.8 | 79.2 |
1000 | 27.5 | 30.8 | 76.4 |
1200 | 27.0 | 29.9 | 70.1 |
1400
|
26.0
|
28.4
|
57.9
|
Due to its austenitic microstructure, Sanicro® 25 has very good impact strength, both at room temperature and at cryogenic temperatures.
Temperature | |||||
---|---|---|---|---|---|
°C | ºF | 10 000 h | 100 000 h | ||
MPa | ksi | MPa | ksi | ||
500 | 932 | 500 | 72.5 | 405 | 58.7 |
550 | 1022 | 380 | 55.1 | 325 | 47.1 |
600 | 1112 | 310 | 45.0 | 230 | 33.4 |
650 | 1202 | 230 | 33.4 | 155 | 22.5 |
700 | 1292 | 145 | 21.0 | 95 | 13.8 |
750 | 1382 | 85 | 12.3 | 50 | 7.3 |
800 | 1472 | 50 | 7.3 | 25 | 3.6 |
Imperial units | Metric units | ||||
---|---|---|---|---|---|
Metal temperature, ºF | Allowable stress, ksi | Allowable stress, ksi 1) | Metal temperature, ºC | Allowable stress, MPa | Allowable stress, MPa 1) |
75 | 27.1 | 27.1 | 40 | 184 | 184 |
100 | 27.1 | 27.1 | 65 | 184 | 184 |
150 | 26.9 | 27.1 | 100 | 174 | 184 |
200 | 25.5 | 27.1 | 125 | 167 | 184 |
250 | 24.3 | 26.9 | 150 | 161 | 181 |
300 | 23.4 | 26.3 | 175 | 156 | 179 |
350 | 22.6 | 25.9 | 200 | 152 | 176 |
400 | 22.0 | 25.5 | 225 | 149 | 174 |
450 | 21.4 | 25.2 | 250 | 146 | 173 |
500 | 21.0 | 25.0 | 275 | 143 | 172 |
550 | 20.6 | 24.8 | 300 | 141 | 171 |
600 | 20.3 | 24.7 | 325 | 139 | 170 |
650 | 20.0 | 24.6 | 350 | 138 | 170 |
700 | 19.7 | 24.5 | 375 | 136 | 169 |
750 | 19.5 | 24.4 | 400 | 134 | 168 |
800 | 19.2 | 24.3 | 425 | 133 | 168 |
850 | 18.9 | 24.2 | 450 | 131 | 167 |
900 | 18.7 | 24.0 | 475 | 129 | 166 |
950 | 18.4 | 23.7 | 500 | 128 | 164 |
1000 | 18.2 | 23.4 | 525 | 126 | 163 |
1050 | 17.9 | 23.0 | 550 | 125 | 160 |
1100 | 17.7 | 22.5 | 575 | 123 | 158 |
1150 | 17.5 | 21.1 | 600 | 122 | 154 |
1200 | 16.2 | 16.2 | 625 | 120 | 140 |
1250 | 12.1 | 12.1 | 650 | 111 | 111 |
1300 | 8.9 | 8.9 | 675 | 85.1 | 85.1 |
1350 | 6.5 | 6.5 | 700 | 64.4 | 64.4 |
1400 | 4.9 | 4.9 | 725 | 48.5 | 48.5 |
750 | 37.1 | 37.1 |
1) Due to the relatively low yield strength of these materials, in some cases slightly higher stress values in this column were established at temperatures where slightly greater deformation was acceptable. These stress values are not recommended in applications where small amounts of distortion can cause leakage or malfunction.
Stress values shown in italics are obtained from time-dependent data.
The maximum use temperature is 1382oF (750oC).
Density: 8.32 kg/dm3; 0.29 lb/in3
Temperature, oC | W/(m oC) | Temperature, oF | Btu/(ft h oF) |
---|---|---|---|
20 | 12 | 68 | 7 |
100 | 13 | 100 | 7 |
200 | 15 | 200 | 7.5 |
300 | 16 | 400 | 9 |
400 | 18 | 600 | 10 |
500 | 20 | 800 | 11 |
600 | 22 | 1000 | 12 |
700 | 23 | 1200 | 13 |
800 | 25 | 1400 | 14.5 |
900 | 27 | 1600 | 15.5 |
1000 | 28 | 1800 | 16.5 |
1100 | 30 | 2000 | 17.5 |
Temperature, oC | J/(kg oC) | Temperature, oF | Btu/(lb oF) |
---|---|---|---|
20 | 470 | 68 | 0.11 |
100 | 485 | 100 | 0.11 |
200 | 500 | 200 | 0.12 |
300 | 520 | 400 | 0.12 |
400 | 535 | 600 | 0.12 |
500 | 555 | 800 | 0.13 |
600 | 570 | 1000 | 0.13 |
700 | 585 | 1200 | 0.14 |
800 | 605 | 1400 | 0.14 |
900 | 620 | 1600 | 0.15 |
1000 | 640 | 1800 | 0.15 |
1100 | 665 | 2000 | 0.16 |
1) Mean values
Temperature, oC | µΩm | Temperature, oF | µΩin. |
---|---|---|---|
20 | 0.98 | 68 | 38.6 |
Temperature, oC | Per oC | Temperature, oF | Per oF |
---|---|---|---|
30-100 | 14.5 | 86-200 | 8 |
30-200 | 1.5. | 86-400 | 8.5 |
30-300 | 16 | 86-600 | 8.5 |
30-400 | 16 | 86-800 | 9 |
30-500 | 16.5 | 86-1000 | 9 |
30-600 | 16.5 | 86-1200 | 9.5 |
30-700 | 17 | 86-1400 | 9.5 |
30-800 | 17 | 86-1600 | 9.5 |
30-900 | 17.5 | 86-1800 | 10 |
30-1000 | 18 | 86-2000 | 10 |
30-1100 | 18.5 |
1) Mean values in temperature ranges (x10-6)
Temperature, oC | Per oC | Temperature, oF | Per oF |
---|---|---|---|
100-200 | 16 | 200-400 | 8.5 |
200-300 | 16.5 | 400-600 | 9 |
300-400 | 16.5 | 600-800 | 9.5 |
400-500 | 17 | 800-1000 | 10 |
500-600 | 18 | 1000-1200 | 10.5 |
600-700 | 19 | 1200-1400 | 11 |
700-800 | 19.5 | 1400-1600 | 11 |
800-900 | 20 | 1600-1800 | 11.5 |
900-1000 | 21 | 1800-2000 | 12 |
1000-1100 | 23.5 |
1) Mean values in intermediate temperature ranges (x10-6)
Modulus of elasticity 1)
Temperature, oC | MPa | Temperature, oF | ksi |
---|---|---|---|
20 | 197 | 68 | 28.6 |
100 | 191 | 200 | 27.8 |
200 | 183 | 400 | 26.5 |
300 | 175 | 600 | 25.2 |
400 | 168 | 800 | 24.0 |
500 | 160 | 1000 | 22.8 |
600 | 153 | 1200 | 21.6 |
700 | 145 | 1400 | 20.3 |
800 | 137 |
1) (x103)
The weldability of Sanicro® 25 is good. Suitable methods of fusion welding are manual metal-arc welding (MMA/SMAW) and gas-shielded arc welding, with the TIG/GTAW method as first choice.
In common with all fully austenitic stainless steels, Sanicro® 25 has low thermal conductivity and high thermal expansion. Welding plans should therefore be carefully selected in advance, so that distortions of the welded joint are minimized. If residual stresses are a concern, solution annealing can be performed after welding.
For Sanicro® 25, heat-input of <1.0 kJ/mm and interpass temperature of <100°C (210°F) are recommended. A string bead welding technique should be used.
TIG/GTAW or MIG/GMAW welding
ISO 18274 S Ni 6617/AWS A5.14 ERNiCrCoMo-1 (e.g. Exaton Ni53, Alloy 617 mod)
MMA/SMAW welding
ISO 14172 E Ni 6117/AWS A5.11 ENiCrCoMo-1
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.