Datasheet updated

2024-01-11 10:30
(supersedes all previous editions)

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.

Square billets
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.

Peel turned round billets
Size Tolerance Length
mm mm m
75 - 200 (5 mm interval) +/-1 max 10
>200 - 450 +/-3 3 - 8
Unground round billets
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)

Metric units
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
Imperial units
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

Metric units
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
Imperial units
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.