The document discusses investment casting and turbine blades. It provides background on investment casting, describing the process of creating a ceramic mold from a wax pattern. Turbine blades are commonly manufactured using investment casting due to its ability to produce parts with complex internal cooling channel designs and intricate geometries from high-temperature superalloys. Investment casting is preferred over alternatives like shell molding and die casting for turbine blades because it allows for greater precision and compatibility with the required materials.

1. Department: Metallurgy Engineering
Subject: Metallurgical Operations Seminar
TITLE: (1) INTRODUCTION OF INVESTMENT CASTING AND
TURBINE BLADE
Name : Aditya Shende (220133121023)
Yash Shinde (220133121025)
GOVERNMENT ENGINEERING COLLEGE
Sector-28, GANDHINAGAR
GUIDED BY : DR. I B DAVE
PROF. D.V. MAHANT

2. Contents
1. Introduction to Casting
2. History Casting
3. Introduction to Investment casting
4. Applications
5. Introduction to Turbine blade
6. Turbine blade filling simulation
7. Turbine blade and Terminology
8. Performance Requirement of Turbine blade
9. Structure of Turbine blade
10. Advantages of investment casting
11. Reasons of not using shell moulding and die casting for
making turbine blades
12. Summary
13. Reference
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3. Introduction to casting
CASTING[1] is the process in which molten metal flows by gravity or
other force into a patterned mold and solidifies in the shape of the mold
cavity. The part produced is called as casting.
• There are five steps in casting process :
1. Pattern making.
2. Molding.
3. Melting and pouring.
4. Fettling or shakeout.
5. Heat treatment (if needed), finishing and inspection
(testing).
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4. History of casting
Fig 1 : History Of casting
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It was in the eighth century
B.C. fist cast iron was first made
by the Chinese, but it was not
until the invention of the blast
furnace by the Europeans in
the 14th century, however, that
large quantities of cast iron
were produced. Interestingly
enough, according to the 39th
census of world casting
production 2004, China was
the leader in casting produc-
tion worldwide

5. Investment casting
Fig 2 : Investment casting
Fig 3 : Investment casting process
Investment casting [2] is a
manufacturing process in which a
wax pattern is coated with a
refractory ceramic material. Once the
ceramic coating material is dry and
hardened, the wax is melted out and
leaves an internal cavity the shape of
the final product's geometry.
[3]
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6. Applications
• Energy: The energy sector has a very specific use for this manufacturing technique.
Wind turbine blades are huge, weigh tons, and require superior strength and
surface finish. This combination of qualities is an advantage of this method.[1]
• Marine: Investment casting of metal parts is common in the marine industry. Strong,
corrosion-resistant metallic panels for ships and submarines are manufactured with
special alloys. Since this method is compatible with numerous metal alloys, it is
well suitable for this application.
• Aerospace: This technique can manufacture crucial parts in aircraft engines and
bodies owing to the requirements of complex geometries and strength.[4]
• Medical: The ability to cast small parts with a superior surface finish puts this
method at an advantage in the medical industry. Prosthetics, implants, and surgical
equipment are some standard applications.
• Automotive: In the automotive industry, high-performance parts like drive train
components, rocker arms, and power train elements are made.
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7. Introduction to Turbine blade
A turbine blade is a specialized component used in turbines,
such as steam turbines, gas turbines, or wind turbines, designed
to capture the energy of a flowing fluid (such as steam, gas, or
wind) and convert it into rotational mechanical energy.[5] These
blades are typically aerodynamically shaped and made from
materials capable of withstanding high temperatures and
mechanical stress, enabling them to efficiently extract energy
from the fluid and drive the turbine's rotation.
Fig 4: Turbine Blade
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8. Turbine blade filling simulation
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9. Turbine blade and Terminology
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10. PerformanceRequirementofturbineblade
• Complex cooling structure: Cooling structure, aiming at reducing the operating
temperature of components, is one of the most crucial measures to improve the
reliability of turbine components working at high temperature.
• Advanced Grain structure: Thermal stress and strain caused by the uneven internal
temperature or constrained expansion of the components under high temperature
will have an adverse effect on the operation of the aero-engine. A rapid increase of
thermal stress in a short time can lead the components to crack, and repeated impact
of thermal stress and deformation can result in the destruction of components. A
typical cyclic loading process is the process of the engine’s starting, accelerating,
decelerating, and stopping.[6]
• Superalloys: The material of turbine blade should maintain reliable working under
high temperature, which requires enough high temperature strength, good thermal
stability, and corrosion resistance of the material. Materials commonly used is cobalt-
based alloy, iron-based alloy. When the temperature is below 700- 800 °C, nickel-
based super alloy. [6]
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11. Structure of Turbine blade
Generally, the external part of blade in high-performance turbine
consists of platform, blade body, and fir tree root.[6] The internal
structure consists of pin fin, longitudinal rib, transverse rib, film hole,
etc., to enhance the heat transfer and improve the heat-resisting
performance of the combustion. The structures of turbine blades are
shown in Fig
Fig 5 : Illustration of turbine blade
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12. Investment casting
Advantages [7]
• Flexible Design
• Superior Surface Finish
• Less Casting Defects,
Improve quality
• Tighter Tolerances, Closer
Net Shapes
• Customizable size and No
Quantity Limitation
Disadvantages
• Longer Casting Cycles
• Quite Expensive
• Labour Intensive
• Difficult to Cast Cores
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13. Shell Moulding
Shell molding is a variation of sand
casting that uses a resin-coated sand
mixture to create molds. It can be
used for turbine blade production
but is less common compared to
investment casting.
Disadvantages : -
• May not be as precise as
investment casting for highly
complex blade designs.
• Limited to certain materials.
Reasonsofnotusingshellmouldinganddie
casting formaking turbineblades[8]
Die Casting
Die casting is commonly used for high-
volume production of parts with simpler
geometries. It involves injecting molten
metal into a mold cavity under high
pressure. While die casting can produce
parts quickly and economically, it is
generally not the preferred method for
turbine blades due to the complexity of
blade shapes and the need for high-
temperature materials.
Disadvantages: -
• Limited to simpler part geometries.
• Not suitable for high-temperature
alloys often used in turbine blades.
• Potential for porosity in the casting.
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14. Summary
Turbine blades are commonly manufactured through investment
casting, which offers precision and complexity for high-
performance designs, including single-crystal blades.
Shell molding is avoided due to limitations in achieving intricate
geometries, while die casting is unsuitable because of its
inability to create the necessary cooling passages and precise
airfoil profiles, along with concerns about rapid cooling affecting
material properties.
Investment casting remains the preferred choice for its ability to
produce intricate, high-quality turbine blades tailored for
demanding applications.
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15. Reference
1. O.P. Khanna, "A Text Book of Foundry Technology", Dhanpat Rai & Sons,
15th Edition, 2011.
2. Peter Beeley “Foundry Technology” A division of Reed Educational and
Professional Publishing Ltd 2nd Edition
3. https://www.google.com/url?sa=i&url=https%3A%2F%2Fmakeagif.com%
2Fgif%2Finvestmentcastinganimation43TiKM&psig=AOvVaw34ATeiGKYDr
YxuSQLPzNC&ust=1693226282097000&source=images&cd=vfe&opi=899
78449&ved=0CBAQjRxqFwoTCNjhpMvt_IADFQAAAAAdAAAAABAD
(Access on 27 August 2023 18:15 PM )
4. P.N. Rao, "Manufacturing Technology", TMH, 5th Edition,2013.
5. Liu DX, Chen G et al (2003) Aero-engine: the heart of airplane. Aviation
Industry Press,Beijing (in Chinese)
6. Turbine blade investment casting die technology by Dinghua Zhang,
Yunyong cheng, Ruisong jiang, Neng wan published by national defence
industry press.
7. https://www.sunrise-metal.com/advantages-and-disadvantages-of-
investment-casting/ (Access on 27 August 2023 18:37 PM )
8. CHAT GPT (Access on 27 August 2023 19:03 PM )
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