FIELD OF THE INVENTION
The present invention generally relates to method for manufacturing the panels for High
temperature and high Pressure applications. More particularly the present disclosure
relates to the process for manufacturing the transition panel with preheating system
and Sequential attachments with Cr – Mo steels.
BACKGROUND OF THE INVENTION
Background description includes information that may be useful in understanding the
present invention.
Coal-fired power plants will continue to contribute a significant part to the supply of
electric power for the country in the near future. To achieve higher efficiency and to
reduce CO2 emissions, the power plants need to be operated at higher steam
temperature above 700° Celsius and higher pressures above 300 kg/cm2. Such plants
are termed as Advanced Ultra Supercritical (AUSC) plants and require the use of
advanced creep resistant material for extended service lives.
In an embodiment of the conventional method, the membrane panels in such Advanced
Ultra Supercritical (AUSC) plants which has High temperature and High Pressure
applications are likely to be subjected to a temperature of about 595°C and pressure of
the order of 390 Kg/Cm2. The conventional membrane panels often suffer from the
problem that it requires material that withstand the steam of such high temperature
and high pressure.
Hence to meet this requirement, the panels are to be fabricated with 9 Cr-1 Mo tubes
and above grades of Cr – Mo steels and fins and process for manufacturing of the
vertical and spiral Panels.

OBJECTS OF THE INVENTION
Considering the above criteria, following analysis have been envisaged to determine the
objective of invention:
It is therefore the object of invention is to develop process for manufacturing the tubes
for panel formation and the panel with the triple elbow and the Spiral Panel with Single
Elbow.
Another object of invention is to develop a heating apparatus to maintain the desired
temperature of the panel during the process for manufacturing the Panel.
These and other objects and advantages of the present invention will be apparent to
those skilled in the art after a consideration of the following detailed description taken
in conjunction with the accompanying drawings in which a preferred form of the present
invention is illustrated.
SUMMARY OF THE INVENTION
One or more drawbacks of conventional transition panels which results that it is not
withstanding the steam of such high temperature and high pressure are overcome, and
additional advantages are provided through a manufacturing process of transition
panels as claimed in the present disclosure. Additional features and advantages are
realized through the technicalities of the present disclosure. Other embodiments and
aspects of the disclosure are described in detail herein and are considered to be part of
the claimed disclosure.
In an embodiment, the manufacturing process according to the present invention
includes all types of panels for heat exchangers/ steam generators such as vertical wall
panels, spiral wall panel, etc. Two variants of tube sizes are being used namely the
Diameter 38.1 mm x 9.0 mm and Diameter 41.3 mm x 8.2 mm. While the former is

used for vertical wall panel, the latter is used in the spiral wall and burner panels. The
transition panel is a combination of vertical and spiral wall panels joined with 9
Chromium-1 Molybdenum elbows.
According to another embodiment of the present invention that includes the pre-heating
apparatus to maintain the panels at a preheat of 220°C to control the distortion during
welding Process.
Various objects, features, aspects, and advantages of the inventive subject matter will
become more apparent from the following detailed description of preferred
embodiments, along with the accompanying drawing figures in which like numerals
represent like components.
It is to be understood that the aspects and embodiments of the disclosure described
above may be used in any combination with each other. Several of the aspects and
embodiments may be combined to form a further embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any way
limiting. In addition to the illustrative aspects, embodiments, and features described
above, further aspects, embodiments, and features will become apparent by reference
to the drawings and the following detailed description.
BRIEF DECSRIPTION OF THE ACCOMPANYING DRAWING
It is to be noted, however, that the appended drawings illustrate only typical
embodiments of the present subject matter and are therefore not to be considered for

limiting of its scope, for the invention may admit to other equally effective embodiments.
The detailed description is described with reference to the accompanying figures. In the
figures, the left-most digit(s) of a reference number identifies the figure in which the
reference number first appears. The same numbers are used throughout the figures to
reference like features and components. Some embodiments of system or methods in
accordance with embodiments of the present subject matter are now described, by way
of example, and with reference to the accompanying figures, in which
Figure 1 illustrates a view of panel formation in panel processing system.
Figure 2 illustrates a view of vertical part of transition Panel.
Figure 3 illustrates a view of Spiral part of transition Panel.
Figure 4 illustrates a typical view of triple Elbow.
Figure 5 illustrates a typical view of single Elbow
Figure 6 illustrates welding of single elbow with the spiral Part of transition Panel.
Figure 7 illustrates welding of Triple elbow with the vertical Part of Transition Panel.
Figure 8 illustrates the assembly of Vertical and spiral Wall of transition Panel.
Figure 9 illustrates the Preheating System Developed to maintain the interpass
temperature during the welding
The figures depict embodiments of the present subject matter for the purposes of
illustration only. A person skilled in the art will easily recognize from the following
description that alternative embodiments of the structures and methods illustrated
herein may be employed without departing from the principles of the disclosure
described herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
PRESENT INVENTION
While the embodiments of the disclosure are subject to various modifications and
alternative forms, specific embodiment thereof have been shown by way of example in
the figures and will be described below. It should be understood, however, that it is
not intended to limit the disclosure to the particular forms disclosed, but on the
contrary, the disclosure is to cover all modifications, equivalents, and alternative falling
within the scope of the disclosure.
The drawings illustrate only those specific details that are pertinent to understand the
embodiments of the present disclosure, so as not to obscure the disclosure with details
that will be clear to those of ordinary skill in the art having benefit of the description
herein.
In an embodiment of fabrication of long transition panels (7) according to the figure 1,
the transition panel (7) consists of 8 tubes (1) of length 1800mm, 38.1x8.12mm
thickness of grade 9 Chromium – 1 Molybdenum material and fin (2) are placed between
each pair of tubes (1) totaling to seven fins and there will be two more additional fins
on the extreme edges on the panel processing apparatus / system.
After completion of welding of the panel, the panel welds are subjected to visual
inspection in order to check for the presence of any distortion or discontinuities like weld
miss, undercuts, porosity etc. Further, the panels are to be subjected to 10% surface
NDT (Non Destructive Testing) for ensuring that the welds are defect free.
In an embodiment of fabrication of long transition panels (7) according to figure 2, the
vertical part (3) of transition Panel consists 24 tubes (1) of diameter 38.1mmx 8.12mm
thickness and length of 900mm with the width over centre of 1248mm. This vertical

part (3) of the panel is cut as per the required length from the long panel into 3 sections
and fitted up along their welding length to form 24 tubes vertical Panel of length 900mm.
In an embodiment of fabrication of long transition panels (7) according to the figure 3,
the spiral part (4) of the transition Panel with the length of 1200 mm and diameter
41.3mmx8.12 mm tube (3) and fin (4) 6mm thickness and length 1150mm. There are
totally 8 tubes (3) and 9 fins (4) in the spiral Part (4) of the Panel and welded along the
sides.
In an embodiment of fabrication of long transition panels (7) according to the figure 4,
the Forged Triple elbow of diameter 38.1x8.12mm thickness is of material grade 9
Chromium – 1 Molybdenum. The forged elbow constitutes the transition of steam into
the vertical Part (3) of the transition Panel (7).
In an embodiment of fabrication of long transition panels (7) according to the figure 5,
the forged Single elbow of diameter 41.31x8.12mm thickness is of material of grade 9
Chromium – 1 Molybdenum. The single elbow constitutes the transition of steam from
the spiral part (4) of the transition panel into the vertical Part (3) of the transition Panel.
In an embodiment of fabrication of long transition panels (7) according to the figure 6,
the welding of the forged single elbow (6) with the tube (3) Spiral Part (4) of the
transition Panel. The TIG welding is carrying out the chamfering the spiral Part of the
tube (3) and grinding the Forged single elbow (6) at the ends and preheating the joint
end up to 220 degrees by using appropriate filler wire and electrode and NDT tests were
carried out for welded joint to meet ASME and IBR code requirements.
In an embodiment of fabrication of long transition panels (7) according to the figure 7,
the TIG welding of the Forged Triple elbow (5) with the tube (1) Spiral Part (4) of the
transition Panel. The TIG welding is carrying out the chamfering the spiral Part of the
tube (1) and grinding the Forged Triple elbow (5) at the ends and preheating all the

joint ends up to 220 degrees by using appropriate filler wire and electrode and NDT
tests were carried out for welded joints to meet ASME and IBR code requirements.
In an embodiment of fabrication of long transition panels (7) according to the figure 8,
joining of the vertical Part (3) of the transition panel (7) along the Forged Triple elbow
(5) with the Spiral part (4) of the transition panel (7) along forged single elbow (6). The
welding was carried out by grinding the joining edges and preheating the edges up to
220 degrees and welding were carried out by using appropriate welding electrode / filler
wire. Penetrant testing was carried out to inspect the welding.
In an embodiment of fabrication of long transition panels (7) according to the figure 9,
the Pre heating Apparatus (8) is developed to maintain the inter pass temperature of
220°C. The pre heating apparatus (8) consists of nozzles (9) which evenly pre heats the
weld surface up to the temperature of 220 degrees.
It will be appreciated by those skilled in the art that the present invention can be
embodied in other specific forms without departing from the spirit or essential
characteristics thereof. The presently disclosed embodiments are therefore considered
in all respects to be illustrative and not restricted. The scope of the invention is indicated
by the appended claims rather than the foregoing description and all changes that come
within the meaning and range and equivalence thereof are intended to be embraced
therein.

Further, the drawings are illustrative only but not used to limit the scope of the present
subject matter. It is to be noted, however, that the appended drawings illustrate only
typical embodiments of the present subject matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally effective
embodiments.

WE CLAIM:
1. A process for manufacturing a transition Panel for high temperature and high
pressure applications comprising the steps of:
- cutting at least a panel tube (1) and at least a fin (2) as per desired length
from a long panel;
- welding the tubes (1) and the fins (2) of desired length between each pair
of tubes (1);
- grinding the ends of at least a forged triple elbow (5) and at least a forged
single elbow (6);
- pre-heating the joint surface of the tubes (1) to be welded at an inter pass
temperature around 220 degrees Celsius;
- welding the forged triple elbow (5) with the tubes (1) to form a vertical part
(3) of the transition panel (7);
- welding the forged single elbow (6) with the tubes (1) to form a spiral part
(4) of the transition panel (7);
- joining the forged triple elbow (5) of the vertical Part (3) with the forged
single elbow (6) of the spiral part (4); and
- subjecting the welded joint surface of the transition panels (7) for visual
inspection and Non-destructive testing to meet ASME and IBR code
requirements.

2. A process for manufacturing of a transition Panel as in claimed 1, wherein the
tubes (1) of the vertical part (3) of the transition panels (7) are preferably made
from material with diameter approximately 38.1mm, and thickness of about
8.12mm.
3. A process for manufacturing of a transition Panel as in claimed 1, wherein the
tubes (1) of the spiral part (4) of the transition panels (7) are preferably made
from material with diameter approximately 41.3mm, and thickness of about
8.12mm.
4. A process for manufacturing of a transition Panel as in claimed 1, wherein the fins
(2) of both the vertical part (3) and the spiral part (4) of the transition panels (7)
are preferably made from material with thickness of about 6mm.
5. A process for manufacturing of a transition Panel as in claimed 1, wherein the
forged triple elbow (5) and the forged single elbow (6) are preferably made of
material grade T91.
6. A process for manufacturing of a transition Panel as in claimed 1, wherein the
tubes (1) of the vertical part (3) and the spiral part (4) of the transition panels (7)
are preferably made of material grade P91.
7. A process for manufacturing of a transition Panel as in claimed 1, wherein the
welding process is preferably carried out by using TIG welding.
8. A process for manufacturing of a transition Panel as in claimed 1, wherein the the
forged single elbow (6) and the forged triple elbow (5) with the tubes (1) is welded
at its chamfered end.

9. A process for manufacturing of a transition Panel as in claimed 1, wherein the
preheating process is carried out by a preheating apparatus (8) which includes at
least a nozzle (9) to evenly preheat the welding surface to an interpass
temperature around 220 degrees Celsius.