Austempering / patenting
Austempering is a special kind of hardening and tempering. After austenitizing in a salt melt at a certain temperature, which lies between the pearlite transformation and the beginning of the martensite temperature, the parts are cooled and ...held for a certain time.
Temperature profile in phases
This so-called isothermal transformation produces a microstructure which is similar both in properties and in appearance to that of the "normal" hardened and tempered structure. When austempering, it is not necessary to temper the parts as well.
Salts for austenitizing
Durferrit manufactures GS salts for austenitizing unalloyed, low and high alloyed steels, and hot and cold work steels within a temperature range of 700 - 1100 °C. Inertors R2 and R3 are added to the GS salts to ensure that decarburization does not take place during austenitizing.
| Non-inert products |
Working temp. |
|
Durferrit GS 540
|
600° - 950° C
|
| Durferrit GS 660 |
750° - 900° C |
| Durferrit GS 670 |
750° - 1000° C |
| Durferrit GS 750 |
850° - 1100° C |
| Durferrit GS 960 |
1000° - 1300° C |
| Inert products |
Working temp. |
|
Durferrit GS 430/R2
|
700° - 800° C
|
| Durferrit GS 540/R2 |
700° - 950° C |
| Durferrit GS 660/R3 |
750° - 900° C |
| Durferrit GS 670/R2 |
800° - 950° C |
| Durferrit GS 750/R2 |
900° - 1100° C |
| Durferrit GS 540/SN 950 |
900° - 1150° C |
| Products containing cyanide |
Working temp. |
|
Durferrit Cecontrol 50 H
|
780° - 950° C
|
| Durferrit Cecontrol 80 B |
800° - 950° C |
| Durferrit GS 540/C3 bzw. Cecontrol |
600° - 950° C |
| Durferrit GS 560/C3 bzw. Cecontrol |
580° - 950° C |
| Durferrit GS 660/C3 bzw. Cecontrol |
700° - 950° C |
| Durferrit GS 670/C3 bzw. Cecontrol |
750° - 950° C |
Salts for isothermal transformation in the bainite range
For the temperature range in which the bainitic transformation takes place, we supply martemper salts with a working temperature of between 180 and 550 °C.
| Products |
Working temp. |
|
Durferrit AS 220
|
250° - 550° C
|
| Durferrit AS 235 |
280° - 550° C |
| Durferrit GS 230 |
270° - 500° C |
| Durferrit GS 430 |
500° - 700° C |
Patenting
In patenting, steel wire or steel strips are quenched from austenitizing temperature into a salt bath at between 400 -500 °C and held there until complete transformation in the pearlite range. After isothermal transformation the wire or steel strips are cooled to room temperature. The ribbon grain pearlite which is formed during patenting is a prerequisite for a successful cold drawing of steel wire and strip.
| Products |
Working temp. |
|
Durferrit AS 140
|
180° - 550° C
|
| Durferrit AS 220 |
250° - 550° C |
| Durferrit AS 235 |
280° - 550° C |
| Durferrit AS 300 |
340° - 550° C |
For austenitizing the above mentioned materials a salt bath with, for example GS 540 or GS 540/R2 can be used. Patenting is then done in a separate salt bath.
© Durferrit GmbH, Industriestrasse 3, 68169 Mannheim
Tel.: +49 (0) 621 32224-0, Fax: +49 (0) 621 32224-809
E-Mail: info@hef-durferrit.com
