X8CrNi25-21 1.4845 BS-EN-10095-1999

X8CrNi25-21 1.4845 BS-EN-10095-1999

Austenitic heat-resisting steels

 Steel designation

NameX8CrNi25-21

Number1.4845

X8CrNi25-21 1.4845 Chemical composition

Cmax.0.10

Si: max.1.50

Mn(max):2.00

P(max):0.045

S(max):0.015

Cr:24~26

Ni:19.00~22.00

N:. max.0.11

X8CrNi25-21 1.4845 Mechanical properties at room temperature

Form: bars

Thickness a or diameter(d:mm): a ≤160

HB max.:192

Proof strength: Rp0,2N/mm² (min):210

Rp1,0N/mm²(min):250

Tensile strength Rm N/mm²):500~700

A % min

Long product:35

Flat products:(1)0,5≤a<3:(1,tr):33   (2)3 < a  (1|tr): 35

Heat treatment

Symbol: +AT (A T=solution annealed)

Temperature(℃):1050~1150

Type of cooling: water, air, cooling sufficiently rapid

Maximum application temperature Ta for air

Ta max(℃):1050

(The loss of metal caused by scaling does not exceed 1 g/m2⋅h at Ta, and does not exceed 2 g/m2 at Ta + 50 ℃ on average for a period of 120 h with four intermediate coolings.)

 

Creep properties

Estimated average value of the strength for 1 % elongation at elevated temperature (Strength in N/mm2)

Elongation 1 % in 1 000 h:

600℃:100

700℃:45

800℃:18

900℃:10

 

Elongation 1 % in 10 000 h:

600℃:90

700℃:30

800℃:10

900℃:4

 

 

Estimated average value of the strength for rupture at elevated temperature

(Strength in N/mm2)

       Rupture in 1 000 h:

600℃:170

700℃:80

800℃:35

900℃:15

 

Rupture in 10 000 h:

600℃:130

700℃:40

800℃:18

900℃:8.5

 

Rupture in 100 000 h:

600℃:80

700℃:18

800℃:7

900℃:3

 

Physical properties for the steels and nickel alloys

Density(kg/dm2):7.9

Linear expansion coefficient (10⁻⁶K⁻¹): between 20℃ and

200℃:15.5

400℃:17.0

600℃:17.5

800℃:18.5

1000℃:19.0

Thermal conductivity

W/(m.K)

      at 20℃: 15

at 500℃:19

 

Specific heat capacity

kJ(kg.k)

        at 20℃:0.50

 

  Electrical resistivity

             Ω.mm²/m

       at 20℃:0.85

 Magnetizability:no (slightly magnetic when cold worked)

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