Fenicro®800Н/НР – Alloy 800Н/НР

Characteristics Fenicro®800Н (description of material No.1.4876 and 1.4958)

Fenicro®800Н is austenitic, heat resisting alloy on the basis of solid solution of Ni-Fe-Cr with the controlled content of carbon, aluminum, titan, silicon and manganese and also controlled total contents (Al+Ti).

The chemical composition is similar to composition of Fenicro®800, however in special processing on solid solution the grain size ≥90µm/ASTM No.4, is formed, which is much higher than a limit of creep resistance 600оС (1110 ° F).

For application at a temperature below 600oС (1110°F), Fenicro®800H is recommended in a condition of the softening annealing.

Fenicro®800 H characterized by:

  • good creep resistance at temperatures above 600oС (1100°F) without loss of plasticity during long use at a temperature lower than 700oС (1290°F) due to limits in content of (Ti+Al) max 0,7%.
  • good resistance in oxidizing, recovery and azotizing atmospheres and also in the atmospheres fluctuating between oxidizing and recovery
  • metallurgical stability at prolonged use at high temperatures.

Characteristics Fenicro®800НP (description of material 1.4959)

Fenicro®800НP is austenitic, heat resisting alloy on the basis of solid solution of Ni-Fe-Cr with the controlled content of carbon, aluminum, titan, silicon and manganese and also controlled total contents (Al+Ti).

As a result of special processing on solid solution the grain size ≥90 µm / ASTM ≥ No.4 is formed, that gives the maximum value of creep resistance higher than 700оС (1290°F), owing to release of carbide of titan.

Below 700oС (1290°F) the γ’ phase in combination with loss of plasticity can be formed.

Fenicro®800НР characterized by:

  • excellent long durability at temperatures above 700oС (1290°F).
  • good resistance in oxidizing, recovery and azotizing atmospheres and also in the atmospheres fluctuating between oxidizing and recovery
  • metallurgical stability at prolonged use at high temperatures. However, in case if usage time frequent temperature drop isn't excluded below 700°С (1290°F) or if parts of material constantly are affected by temperature below 700°С (1290°F), then it is recommended to use Fenicro®800НР.

 

Type of structure

Fenicro® 800Н and Fenicro® 800НР are austenitic, hardened on solid solution alloys with the small content of the emitted nitrides and carbides of the titan, carbonitrides and carbides of chrome. During long operation at a temperature lower 7 000С in alloy Fenicro® 800Н g’-phase, which is reducing plasticity, can be formed.

At Fenicro® 800HP alloy g’-phase, connected with loss of plasticity, is allocated.

Sensitivity to cracking as a result of stress relaxation.

Fenicro® 800Н and Fenicro® 800НР are subject to relaxation cracking in case products processed on solid solution are operated at temperature interval 550-7500С (1020-1380°F). High extents of cold deformation and process of welding during production lead to cracking as a result of stress relaxation during operation.

Stabilizing heat treatment at temperature 9800С (1800°F) with holding during 3 hours for material before processing or welding and also for materials which already were in use, it is practically eliminates susceptibility to relaxation cracking.

However, for a full guarantee of elimination of relaxation cracking, the welded parts have to be subjected to postwelding heat treatment (PWHT) according to the above-stated stabilizing heat treatment of a material basis at temperature 980°С. In that case if welding is carried out with the corresponding materials on the Fe-Ni basis (type 82), then carrying out (local) PWHT is possible at temperature 875°С during 3 hours. If welding is carried out with filler materials on Ni basis, type 617, then (local) PWHT is necessary at temperature 9800С (1800 °F) with holding for 3 hours. Speeds of heating and cooling for similar heat treatments aren't critical.

Grades and standards of alloys Fenicro®800Н – Alloy 800H

Country

Standard

Material description

Germany

EN DIN

1.4958

X5NiCrAlTi31-20

DIN

WdT UV-Wbl

UK

BS

NA 15(H)

USA

ASTM

UNS N08810

ASME

ASME code case

 

Grades and standards of alloys Fenicro®800НP – Alloy 800HP

Country

Standard

Material description

Germany

EN DIN

1.4959

X8NiCrAlTi32-21

DIN

USA

ASTM

UNS N08810

Mechanical properties

The following mechanical properties are valid for alloy after processing for solid solution in the specified sizes. Additional coordination of properties is necessary if material doesn't correspond to the specified sizes. Values are valid for longitudinal and cross tests.



Typical physical properties at room and high temperatures

Density

8,1 g/cm3

0.293 lbf/in3

Melting range,

1350-1370°C

2460-2500°F

Magnetical inductive capacity at 20°С/68°F

<1.001

Chemical composition (% on weight)

 

Ni

Cr

Fe

C

Mn

Si

Cu

Al

Ti

Al+Ti

P

S

Fenicro®800Н

Alloy 800H

Min

30.0

19.0

rest

0.06

0.5

0.2

 

0.2

0.2

 

 

 

Max

32.0

22.0

0.08

1.5

0.7

0.5

0.4

0.5

0.7

0.015

0.01

Fenicro®800НP

Alloy 800HP

Min

30.0

19.0

rest

0.06

0.5

0.2

 

0.3

0.3

 

 

 

Max

32.0

22.0

0.1

1.5

0.7

0.5

0.6

0.6

1.2

0.015

0.01