FILED OF THE INVENTION
The present invention relates to development an improve grade of
steel which contains a dual phase (ferrite bainite or ferrite
Martensite) after cooling in As-Cast Condition adaptable to make thin
Steel strip.
BACKGROUND OF THE INVENTION
Duel phase steel posses ferrite rich micro-structure with a dispersion
of some 10-20% vol of a hard phase. The second phase constitutes
of either bainite or martensite or combination of both, with or
without traces of retained austenite. These are also some times
referred as multi phase steels and are produced either by controlling
the transformation of austenite after hot rolling or by interstitial
annealing after cold rolling. The present invention discloses a steel
which generates a microstructure containing dual phase directly
during cooling after solidification of the steel, discarding any high
temperature solid state transformation or rolling or annealing.

OBJECT OF THE INVENTION
It is therefore, an objection of the present invention to proprose an
improved grade of steel that contains a dual-phase in as-cast
condition which eliminates the disadvantages of the Existing Art.
Another objection of the present invention is to propose an improved
grade of steel that contains a dual phase in as-cast condition which
discards additional steps of operation without in pairing physical
properties.
A further object of the present invention is to propose an improved
grade of steel that contains dual phase in as-cast condition which
reduces the cost of production of steel.
SUMMARY OF THE INVENTION
About 25kg of the alloy was made in laboratory using a simple air
induction furnace as per conventional steels making process. To
stabilize ferrite over a wide range of temperature an addition of
alumimium content made in low carbon steel. Some amount

molybdenum in the alloy would ensure sufficient hardentrility of the
austenite so that the hard phase of bainite or martensite can be
obtained. The liquid metal was cast in a preheated metal mould and
allowed to cool at industrial cooling, obtained the following
composition
C- 0.02-0.3. (wt%)
Al- 0.1-2 (wt%)
Mo -0.1-1 (wt%)
Fe - rest.
METALLOGRAPHY TEST
A sample was cut from the cast ingot and polished and etched with
2% nital. The sample was then examined using an optical
microscope and filed emission gun scanning electron microscope
(FEGSEM).

RESULTS
Figure 1, reveals the materials in as-cast condition is comprised of
two differently etched phases. The light-etched coarse grains with
somewhat irregular grain boundaries dominate the microstructure.
These appear to be the grains of δ-ferrite arising out of the molten
metal during solidification. The second phase appearing with a dark
contrast at room temperature is supposed to be austenitic at high
temperatures, formed from the δ-ferrite. The austenite is seen to
have nucleated both at the grain boundaries and within the grains of
5-ferrite. During cooling, this austenite has transformed into some
other product, the nature of which is not clear from the micrographs.
Figure 2, reveals vividly the plates or laths of bainitic ferrite
constituting the second phase. The interlath regions are comprised
of innumerable small plates similar to martensite, with an
intervenening grey contrast that appears to be due to traces of
untransformed austenite.

WE CLAIM
1 An improve as-cast dual phase steel after cooling comprising:-
C - 0.02-0.3. (wt%)
Al- 0.1-2 (wt%)
Mo-0.1-1 (wt%
Fe - rest.
Characterized in that the said grade of steel develops a dual phase
only by cooling without impairing any physical property and
adaptable to make thin steel strips with low cost of production.

About 25kg of the alloy was made in laboratory using a simple air
induction furnace as per conventional steels making process. To
stabilize ferrite over a wide range of temperature an addition of
alumimium content made in low carbon steel. Some amount
molybdenum in the alloy would ensure sufficient hardentrility of the
austenite so that the hard phase of bainite or martensite can be
obtained. The liquid metal was cast in a preheated metal mould and
allowed to cool at industrial cooling, obtained the following
composition
C- 0.02-0.3. (wt%)
Al- 0.1-2 (wt%)
Mo -0.1-1 (wt%)
Fe - rest.