FIELD OF INVENTION
The present invention relates to a device for holding austenitic stainless steel
samples during electrolytic etching for microscopic examination. More
particularly, the invention relates to a device which is capable of holding all types
of austenitic stainless steel samples without manual vibrations, keeping the
current stable, hence improving the quality of etching.
BACKGROUND OF INVENTION
All the austenitic stainless steel samples that come for bead height (if welded)
testing, microstructure testing, Intergranular corrosion susceptibility testing are
to be first prepared by grinding the specimen on a series of emery papers of
decreasing grit size, followed by final polishing in one or more cloth covered lap
wheels. These operations ultimately produce a flat, scratch free, mirror-like
surface, which is to be electrolytically etched using electro etching equipment for
any kind of microscopic examination.

The electrolytic etching method consists of passing a direct current (lA/cm2),
through a suitable electrolyte (10% oxalic acid solution), for the desired time
period, wherein the specimen to be etched is usually made the anode. The
specimen is held using tong provided with the instrument. The current is to be
set based on the area of the sample exposed (current - lA/cm2) in the
electrolyte. For setting the current, one person has to press the scale changing
knob (changing the scale to 0.1 scale) using one hand and with the another the
current has to be set. Another person holds the sample in the electrolyte and
monitors the time. This procedure generally requires the involvement of two
persons and as the sample keeps shaking when held manually, this affects the
set current and hence, in turn effects the quality of etching.
So to save the man power required in etching and also to improve the quality of
etching, a device is needed which can hold the sample with stability for the
required time, requiring only one person to set the current and monitor the
procedure.

OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose a device for holding
austenitic stainless steel samples during electrolytic etching for microscopic
examination, which is capable of holding all types of austenitic stainless steel
sample without manual vibrations, keeping the current stable and improving the
quality of etching.
Another object of the invention is to propose a device for holding austenitic
stainless steel samples during electrolytic etching for microscopic examination,
which is able to perform the task of electrolytic etching with only one person.
SUMMARY OF THE INVENTION
The invention relates to a device attached with timer/stop watch and a tong
having tong mouth to hold the austenitic stainless steel sample for electrolytic
etching with complete stability and requiring only one person to set the current
and monitor the procedure. The device is provided with a long rod of steel
welded to a steel base. Insulation is provided between the tong and the rod.
Current is set and stop watch is monitored. The sample is etched for 1.5 minute

at lA/cm2. The sample is then removed, washed thoroughly followed with drying
to make the sample ready for any kind of microscopic examination.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig.l - Shows unmoulded austenitic stainless steel sample.
Fig.2 - Shows moulded austenitic stainless steel sample.
Fig.3 - Shows the device for holding the sample according to the
invention.
Fig.4 - Shows complete arrangement for electrolyte etching of the sample
in accordance with the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Fig.l shows austenitic stainless steel sample for microscopic examination
(microstructure, bead height for welded tube), Intergranular susceptibility test
etc. The sample is moulded, if required by keeping the required amount of
unmoulded surface (2) to hold the sample for electrolytic etching, as shown in

Fig.2. Otherwise, it is prepared as such by grinding the specimen on a series of
emery papers of decreasing grit size (80,220,400 and 600) followed by final
polishing in cloth covered lap wheels using diamond polish paste. These
operations ultimately produce a flat, scratch free mirror like surface.
The area of the base of the specimen which will come in contact with the
electrolyte is measured and based on which the current is set. The requirement
of current for austenitic stainless steels, is lA/cm2 (ASTM A262).
As shown in Fig.3 the specimen (1) is fitted in the device (5) such that the base
of the specimen is in contact with the electrolyte (8) which is 10% oxalic acid,
contained in a beaker (4). The device (5) is provided with a long rod of steel (7)
welded to a steel base (6) so that sample of any height can be adjusted. A tong
(10) is attached with the rod (7) to hold the samples. One hand (18) of tong is a
free hand to adjust sample of any size. The mouth of tong (14) holds the
sample. The tong (10) is having a free vertical movement (13) with the help of
adjustable screw (12) for its adjustment according to sample height. The tong
mouth (14) is made in such a manner that the sample of any diameter can be
held without slipping. Insulation (11) is provided between the tong (10) and the

rod (7) to prevent the flow of current in the rod or the base. A flexible sheet (15)
is disposed in between the hands of the tong (10) to provide elasticity and
holding grip. A timer/stop watch (16) is attached with the device (5) to monitor
the time of etching accurately. The wire (17) connecting the device (5) with the
electro etch equipment is soldered.
The complete set up is shown in Fig.4. Current is set using the lower scale
factor. The equipment (19) is turned ON and the stop watch (16) is monitored.
The sample is etched for 1.5 min at lA/cm2. After 1.5 minutes, the sample is
removed from the device (5) and washed thoroughly followed with drying when
the sample becomes ready for any kind of microscopic examination.

WE CLAIM
1. A device for holding austenitic stainless steel samples during electrolytic
etching for microscopic examination, the said device comprising;
a long rod of steel (7) welded to a steel base (6) allowing
adjustment of any height of the sample;
Characterized in that,
a tong (10) is attached with the rod (7) for holding the sample (1),
when a tong mouth (14) disposed in the tong (10) for holding sample of
any diameter without slipping, where one hand (18) of the tong is left free
for holding sample of any size, when an adjustable screw (12) is disposed
in the tong for facilitating free vertical movement of the tong for adjusting
the sample height, wherein a flexible sheet (15) is disposed between the
hands of the tong for providing elasticity and holding grip for free hand
(18) of tong when a timer/stop watch (16) is attached with the device for
accurately monitoring the time of etching, wherein a beaker (4) containing
electrolyte and being connected (20) with the electro etch equipment (19)
is disposed under the sample for allowing the sample to be dipped in
electrolytic solution (8).

2. The device as claimed in claim 1, wherein the device (5) and the electro
etch equipment (19) are interconnected by a soldered wire (17).
3. The device as claimed in claim 1, wherein the tong and rod being
insulated prevents flow of current in the rod (7) or base (6).

ABSTRACT

The present invention relates to a device (5) for holding austenitic stainless steel
samples during electrolytic etching for microscopic examination. The device
comprising of a long rod (7) of steel welded to a base (6) of steel which allows
adjustment of sample of any height. A tong (10) attached to the rod (7) has a
tong mouth (14) to hold the sample. The tong has a free vertical movement with
the help of a adjustable screw for adjusting the sample (1) according to its
height. The tong mouth (14) can hold the sample of any diameter without
slipping. One hand (18) of the tong is left free to hold the sample of any size.
Elasticity and holding grip is provided by using flexible sheet (15) between the
hands of the tong (10). A timer/stop watch is attached with the device (5) to
accurately monitor the time of etching. Wire (17) connecting the device with the
electro etch equipment is soldered. Insulation is provided between the tong (10)
and the rod (7) to prevent flow of current in the rod (7) and base (6).