What Is The Difference Between Ferrite And Austenite Steel

What Is The Difference Between Ferrite And Austenite Steel

The major difference is in the composition. Also the most known difference is the magnetic features. The ferrite materials are magnetic whereas the austenite is non-magnetic. The austenitic stainless steels contain chromium from 16% to 26% depending on the different grades of the austenitic stainless steel. Austenitic steels can be hardened by heat treatment, however they cannot be strengthened by heat treatment. Ferrites are stronger but has less corrosion resistant. They are also ductile and can be formed and machined much better than the austenitic stainless steels.


Ferrite And Austenite Microstructure

Austenite is a heat capable phase of steel. The austenitic steels are also known are stainless steels. The ferritic microstructure can be hard ferrite or soft ferrite. The hard ferrites are difficult to demagnetize and the soft ferrites are easy to demagnetize. The austenitic stainless steels are non-magnetic and the microstructure cannot be altered by heat treatment. The ferrite microstructure can be altered by heat treatment and most ferrites lose their magnetic conditions after heat treatment.

Carbon Solubility In Ferrite And Austenite

The austenitic microstructure allows for carbon solubility more than the ferrite materials. The austenitic stainless steels have different amounts of carbon depending on the different grades of steels. The ferrite materials are used in applications that require magnetic properties and cheaper materials. These are useful in magnetic cores where the electric conductivity, magnetic properties and strength are preferable for the ferrite materials.


Density Of Ferrite And Austenite

Ferrite materials don’t much additions of other materials. The chromium and nickel contents of the austenitic materials increase the density of the austenitic stainless steels. Most austenitic stainless steels have densities above 8 grams per centimeter cube. The density also helps the austenitic materials to be used in high sensitive applications and high end industrial applications. The uses of ferritic materials are in the low range of applications where the austenitic stainless steels are used in petroleum, petrochemical, pharmaceutical, food production, heat exchangers and other industrial applications.

Hardness Of Ferrite And Austenite

The ferritic materials are soft compared to the austenitic stainless steel grades. The inclusion of nickel and chromium contents in the austenitic stainless steel grades improve the hardness and reduce the ductility. The high hardness helps the austenitic materials to be used in construction, transportation and in engineering applications. The ferritic materials have low hardness but high ductility. These properties help the ferritic materials to be used in highly welded, formed and machined applications with low cost.

 

equivalent material grades of Austenite steel
AUSTENITE STEEL

UNS NO

BS

EURONORM NO.

301

S30100

301S21

1.4310

302

S30200

302S25

1.4319

303

S30300

303S31

1.4305

304

S30400

304S31

1.4301

304L

S30403

304S11

1.4306

304H

S30409

-

1.4948

(302HQ)

S30430

394S17

1.4567

305

S30500

305S19

1.4303

309S

S30908

309S24

1.4833

310

S31000

310S24

1.4840

310S

S31008

310S16

1.4845

314

S31400

314S25

1.4841

316

S31600

316S31

1.4401

316L

S31603

316S11

1.4404

316H

S31609

316S51

-

316Ti

S31635

320S31

1.4571

321

S32100

321S31

1.4541

347

S34700

347S31

1.4550

403

S40300

403S17

1.4000

405

S40500

405S17

1.4002

409

S40900

409S19

1.4512

410

S41000

410S21

1.4006

416

S41600

416S21

1.4005

420

S42000

420S37

1.4021

430

S43000

430S17

1.4016

440C

S44004

-

1.4125

444

S44400

-

1.4521

630

S17400

-

1.4542

(904L)

N08904

904S13

1.4539

(253MA)

S30815

-

1.4835

(2205)

S31803

318S13

1.4462

(3CR12)

S41003

-

1.4003

(4565S)

S34565

-

1.4565

(Zeron100)

S32760

-

1.4501

(UR52N+)

S32520

-

1.4507

 

grades of Austenitic stainless steel
  • 310
  • 304L
  • 309
  • 304H
  • 304
  • 347
  • 316
  • 321
  • 304N
  • 308L

 

austenite steel Characteristics
  • High Formability
  • Low Thermal Conductivity
  • Strength at Temperature up to approximately 1900F
  • Cold Workability

 

chemical composition table of Austenitic stainless steel
GRADE COMPOSITION MICROSTRUCTURE
  SI C MN OTHERS NI CR MO AUSTENITE
FERRITE
304L   0.75 0.035 2.0 - 8/11 18/20 - A + 2/8%F
304   0.75 0.08 2.0 - 8/11 18/20 - A+2/8%F
304N   0.75 0.08 2.0 0.1/0.16N 8/11 18/20 - A + 2/8%F
304H   0.75 0.04 - 0.10 2.0 - 8/11 18/20 - A + 2/8%F
347   0.75 0.08 2.0 Nb : 10xC 9/13 17/20 - A + 4/12%F
316   0.75 0.08 2.0 - 11/14 16/18 2/3 A + 3/10%F
308L (generally filler metal only)   1.0 0.03 2.0   10/12 19/21   A + 4/12%F
310   0.75 0.15 2.0 - 19/22 24/26 - 100% A
321   0.75 0.08 2.0 Ti: 5xC 9/12 17/19 - A + 4/12%F
309   1.0 0.08 2.0 - 12/15 22/24 - A + 8/15%F

 

austenite steel Mechanical database
  TENSILE STRENGTH YIELD STRENGTH

Austenitic

600

250

Duplex

700

450

Ferritic

500

280

Martensitic

650

350

Precipitation Hardening

1100

1000

 

grades of Ferrite stainless steel
  • 434 stainless steel
  • 446 stainless steel
  • 430 stainless steel
  • Type 409 stainless steel
  • Type 442 stainless steel
  • 439 stainless steel
  • 430LI stainless steel
  • 444 stainless steel

 

Physical properties of Ferrite stainless steel

Property

Ferritic

Density Value (kg/m3)

7700

Thermal conductivity

(20°C, W/m.°C

25

Thermal expansion

(0-100°C μm/m/°C)

10.5

Electrical resisivity

(nΩ.m)

600

Specific heat range

(0-100°C, J/kg.°C

430-460

 

ferrite stainless steel Yield Strength

Common name

Yield MPa

Tensile

MPa

Elongation at break %

Modulus

GPa

409

170

380

20

220

4003, 3/5Cr12

L:320

T:360

480

18

220

430

205

450

22

220

444

275

415

20

220

304

270

650

57

200

Carbon steel

300

430

25

215

 

Composition analysis of Ferrite stainless steel

Typical composition (%)

AISI

C

Cr

Mo

Other

410S

0.08

12

   

409

0.03

11

 

0.5 Ti

430

0.08

17

   

430Nb

0.05

17

 

0.6 Nb

430Ti

0.05

17

 

0.6 Ti

434

0.08

17

1

 

444

0.02

18

2

0.4 (Ti+Nb)

446

0.15

24

 

 

447

0.01

29

3.8

0.1Cu, 0.1Ni