The document discusses various heat treatment processes for metals, including surface hardening techniques like nitriding, nitrocarburizing, and case hardening. It provides details on common nitriding and nitrocarburizing procedures, how case hardening enriches the surface with carbon before hardening, and bainitic quenching which involves quenching steel in a salt bath between 250-400°C. The document also describes Härtetechnik Hagen GmbH, a German company that has offered heat treatment services using salt baths and protective gases since 1968, including nitriding, nitrocarburizing, and their proprietary FER-N-OX process.

1. Surface-harden
Heat treating of
steel
How heat is optimizing steel
for individual purposes

2. Heat treatment of metals
The heat treatment of
metals is a thermal or
thermo-chemical process
with the aim of changing or
improving the mechanical
properties of a component.

3. Heat treatment of metals
A basic distinction is made
between processes that cause
changes in the entire
component structure due
to structural change (e.g.
hardening, annealing) or only
result in changes to the
material surface (e.g.
nitriding, case hardening).

4. Nitriding & Nitrocarburizing
Nitriding and
nitrocarburizing is a widely
used surface hardening
process in practice. The
following procedures are
standard procedures:
1.Gas nitriding 480 ° - 570 ° C
2. Gas nitrocarburizing
500 ° - 630 ° C
3. Salt bath nitriding
550 ° - 580 ° C
4.Nitrocarburizing with
oxidizing 510 ° - 630 ° C
5.FER-N-OX © 530 ° - 630 ° C
6. Glow under protective gas

5. Case hardening
Case hardening also belongs
to the group of thermo-
chemical diffusion processes
and describes a heat treatment
process in which the surface of
the component is enriched with
carbon before the actual
hardening.
For this purpose, the workpiece
is heated in an atmosphere with
sufficient carbon content and
held for a correspondingly long
time at certain temperatures, as a
result of which the desired
carburization or carbon
diffusion is achieved.

6. Bainitic Quenching
Bainitic quenching is a quenching of
hardening temperature (austenitizing
temperature) in a salt bath.
This salt bath is operated between
250 ° &400 ° C depending on the
requirements and the type of steel.
The parts are kept in the salt bath until
the transformation is complete. Once
the conversion is complete, the cooling
can take place as desired.
However, it is necessary that the
salt baths have a certain volume so
that the set quenching temperature is
not changed significantly by the
introduction of massive glowing
parts. Our currently largest salt bath
has a content of approx. 25t.

7. Härtetechnik Hagen GmbH
Härtetechnik Hagen GmbH
as a medium-sized company
with around 50 employees
has been working in the field
of finishing steel parts since
1968.Always looking for new,
innovative processes, we
switched from pure salt bath
technology to protective gases
and their advantages at an
early stage. The nitriding,
nitrocarburizing, with and
without post-oxidation should
be mentioned above all.
With a process developed by
us, which was registered and
protected under the name
FER-N-OX in 1997 as a brand
name.

8. Härtetechnik Hagen GmbH
Härtetechnik Hagen GmbH
Tiegelstr. 2
58093 Hagen
+49 (0) 2331 3581-0
https://haertetechnik-hagen.de