Fenicro®28 – Alloy 28

GENERAL INFORMATION

Fenicro®28 is austenitic, low-carbon Fe-Ni-Cr-Mo alloy with addition of 1-1,4% of Cu.

Due to very low content of carbon, as well as high content of chrome in combination with molybdenum and copper, alloy has very good corrosion resistance at general application and besides is excellently resistant against pitting and crevice corrosion.

Fenicro®28 is characterized by:

- good resistance to numerous        corroding environments, including mineral and organic acids with impurity, exclusive resistance to phosphoric acid;

- excellent firmness against pit, gap, intercrystal corrosions, and to corrosion cracking;

- good mechanical properties.

 

Application area

  • devices for production of phosphoric acids by method of liquid reagent processing, in particular the heatexchange device in thickener where phosphoric acid resistance is necessary, containing free halogenides.
  • the condenser above a rectifying column at process of purification of oil
  • Pipes and heat exchangers which are carrying out the sulfuric acid containing chlorine
  • the pipelines, condensers, coolers, etc. which are carrying out sea water
  • production pipes, covering and inserts of transportation of sulphurous gas. Material is used after cold processing for ensuring the highest mechanical durability
  • installations for evaporation of salts for the purpose of stability to chloride of sodium and crystals of salts.

 

Ppocessing and heat treatment

Hot processing by pressure.

Fenicro® 28 is possible to subject to hot processing by pressure in the field of temperatures between 1200 and 10600С in the conclusion with the subsequent hardening in water or the accelerated cooling on air.

Heat treatment after hot processing by pressure is recommended for achievement of optimum corrosion properties.

For heating, products should be loaded into the furnace at the maximum working temperature.

Cold processing by pressure.

Cold processing has to be carried out on the material processed on solid solution. Fenicro® 28 has higher peening than austenitic stainless steels. At the choice of devices for processing by pressure it is necessary to consider it. At strong draftings intermediate annealings are necessary.

At draftings above 15% is necessary to carry out repeated annealing.

 

 

Grades and standards

 

Country

Standard

Material description  

Germany

SEW

VdTÜV

1.4563

X1NiCrMoCuN31274

France

AFNOR

Z1NCDU 31.27

USA

ASTM

ASME

UNSN08028

ISO

FeNi31Cr27Mo4Cu1

Heating

The processed products have to be cleaned and not contain any impurity both before, and during heat treatment.

Fenicro® 28 can lose the properties when heating in the presence of such impurity as sulfur, phosphorus, lead and other metals with a low temperature of melting. Marking and thermometric paints and pencils, lubricants, liquids and combustible materials can be a source of similar impurity.

Fuel has to contain as little as possible sulfur. No more than 0,1% on the mass of sulfur have to contain the natural and lowered oil gas, and household gas to contain no more than 0,25 g/m3 of sulfur. Content of sulfur in liquid fuel has to be not higher than 0,5% on weight.

The atmosphere of the furnace has to be neutral or slightly oxidizing. It is necessary to avoid fluctuation of the atmosphere of the furnace between oxidizing and recovery and also direct impact of a flame on metal.

 

Corrosion resistance

Fenicro®28 has excellent resistance to pitting and crevice corrosion. The indication of resistance against pitting corrosion is result of pitting agents sum = % Сг + 3,3 % Мо. It specifies that Fenicro®28 is the most resistant of widespread nickel alloys and also among stainless steels of 300 type. Good general resistance to corrosion cracking and to chloride-induced corrosion cracking. Alloy is also resistant against intercrystalline corrosion.

At production of phosphoric acid materials are most subject to influence of halide impurities in phosphoric ores. It is proved that Fenicro®28 is the most resistant among all austenitic alloys applied at stages of evaporation and filtration of this process.

Fenicro®28 has been created for the solution of these corrosion problems. It shows good firmness in sulfuric and nitric acids, organic acids (such as acetic and ant) and mixes from organic acids.

It isn't subject to action salt, fluoric and silicon fluoric and hydrogen acids and therefore alloy can be applied in processes, where the specified chemical compounds  contain.

Also alloy has good stability in sea water.

Chemical composition, %

 

Ni

Cr

Fe

C

Mn

Si

Cu

Mo

Nb

P

S

Min

30.0

26.0

base

 

 

 

1.0

3.0

0.04

 

 

Max

32.0

28.0

0.015

2.0

0.7

1.4

4.0

0.07*

0.020

0.010

Mechanical short-term properties Fenicro®28, minimal values

Shape

Sizes

Yield strength

Yield strength

Tensile strength

Elongation

Hardness

mm

in

σ0,2

N/mm2

ksi

σ1,0

N/mm2

ksi

σв

N/mm2

ksi

δ5, %

НВ

Sheet, strip

≤5

≤0.2

220

31.9

250

36.3

500

72.5

35

≤220

Plate

≤5-20

>0.2-2

210

30.5

240

34.8

Rod, bar

≤250

≤10

210

30.5

240

34.8

Pipe

≤5

≤0.2

220

31.9

250

36.3

>5

>0.2

210

30.5

240

34.8