Metallurgical processes in welding

1.

Metallurgical processes in
welding.
The work was prepared by
Students of group 1-24
Kovalchuk N.A.
Ivanov A.S.

2.

1.Introduction
Welding is the process of
joining metals, which is used in
various industries, including
construction, automotive
manufacturing, and equipment
production.
Img. 1 - Welding process

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2. The main metallurgical
processes in welding.
1
Introduction
2
The heating process
3
The melting process
-A brief overview of heating
and melting.
- Various types of welding
- Temperature distribution
- Influence of properties
-Metal melting
-Formation of a liquid bath
-Coagulation and solidification
Img. 2 Formation of a liquid bath
Img. 3 - Welding process

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3. Crystallization
Crystallization is the process in which
molten metal transitions to a solid state,
forming a crystalline structure.
The crystallization process:
-Cooling and solidification
-Crystal formation
-The effect of the cooling rate
Img. 4 The crystallization process

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4. Influence of Alloy Composition
Alloying elements, such as nickel, chromium,
and molybdenum, can significantly affect the
crystallization processes. They can alter the
melting temperature and promote the
formation of various phases during
solidification.
Img. 5-7 Nickel, chromium, and
molybdenum

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5. Diffusion
Diffusion — This is the process of the
movement of atoms or molecules in a
material, which plays an important role in
the formation of the properties of welded
joints..
Types of diffusion
-Frontal
-Solid-state
Influence of temperature
-As the temperature increases,
the rate of diffusion increases.
-In the molten state, diffusion
occurs much faster than in the
solid state
Img. 8 Solid-state diffusion at the moment
of contact and after 5 years.

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5. Formation of thermally treated
zones.
-Welded joint zones
1.Welding zone (WZ)
2.Thermally treated zone (TTZ)
3.Base metal (BM)
-Processes of forming the TTZ
1.Heating
2.Cooling
3.Recrystallization
-Microstructural changes
1.Change in grain size
2.Formation of new phases
3.Presence of residual stresses
Img. 9 Processing

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6. Formation of defects
-Main types of defects in welding
1.Internal defects
2.Surface defects
3.Geometry defects of the weld
-Causes of defect formation
1.Incorrect choice of welding technology
2.Non-optimal welding parameters
3.Surface preparation issues
-Methods for preventing defects
1.Proper selection of equipment
2.Process parameter control
3.Thorough preparation
Img. 10 Examples of welding defects

9.

List of literature
1. Ryabov, A. N. "Welding Metallurgy." Moscow: Metallurgia, 2015.
2. Kuznetsov, V. I. "Welding Technologies." Moscow: Machine
Engineering, 2018.
3. Burtsov, S. A. "Physics and Metallurgy of Welding.«
Moscow: Nauka, 2020.
And some additional online resources.

10.

List of sources for gathering material for the presentation
1.
2.
3.
1. youtube.com/watch?v=gAOGTz6f7Osgrfg
2.Interactive Whiteboard Guide: Visual Physics. 7th Grade
3.ru.pinterest.com/pin/chromium_metal—363243526171736370
4.https://bstudy.net/606601/tehnika/strukturnye_prevrascheniya_svar
nom_okoloshovnoy_zone_gazovoy_svarke

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Thanks for your attention!