Annealing And Hardening
Annealing salts are usually used in combination with an additive to prevent decarburization and oxidation of the treated components. The risk increases considerably as the treatment temperature rises. Depending on the mode of action, additives are divided into two groups.
The cyanide-free products bind successfully oxygen containing compounds and ensure the inert character of the melt. They can be used up to a temperature of 1100 °C.
The second class of additives gives the melt a certain carbon activity, which depends on both the concentration of the additive and the nature of the base salt. Due to the short treatment times the carbon activity is allowed to vary considerably from the carbon content of the steel and has not to be adjusted within close limits.
As an alternative to the classic GS products, the modern DUROFER® process for hardening being free of decarburization has proven itself in practice. (see Carburizing and Carbonitriding page 4)
Base Salt
|
Product |
Application |
Working |
|
GS 230 |
For tempering and quenching above 300 °C. |
|
|
GS 430 |
For tempering, cooling or quenching of steel for which AS baths are not suitable. |
500 – 700 |
|
GS 520 |
Replenishment salt for GS 430 baths. |
|
|
GS 540 |
For heating and annealing. |
600 – 950 |
|
GS 560 |
Barium free salt for annealing silver, gold and brass. |
600 – 850 |
|
GS 660 |
Barium free salt for annealing steel and non-ferrous metals. |
750 – 900 |
| GS 670 | For heating and annealing. | 750 – 1000 |
| GS 750 | For heating and annealing. | 850 – 1100 |
|
GS 960 |
For heating and annealing. |
1050 – 1250 |
Additive salts for inert annealing; cyanide-free
|
Product |
Application |
|
|
R 2 |
For the prevention of decarburization and oxidation in combination with GS 540, GS 670 and GS 750 |
|
|
R 3 |
Barium-free additive for the prevention of decarburization and oxidation in combination with GS 670 |
|
Additive salts for preventing decarburization
|
Product |
Application |
|
| C 1 | For the prevention of decarburization and oxidation in combination with GS 540, GS 560, GS 660 and GS 670; is used, if the carbon content of the C 3 is undesirable
|
|
| C 3 | For the prevention of decarburization and oxidation in combination with GS 540, GS 560, GS 660 and GS 670; contains active carbon to form a bath cover |
C3: For the prevention of decarburization and oxidation in combination with GS540, GS 560, GS660, GS 670. Contains active carbon to form a bath cover.