Telegram Group for all Students and Teachers (Pot of Knowledge)
https://t.me/ASKAzadMechanicalEngineering


Abhinandan Kumar

In this course, the educator discusses how molten metal flow during welding and its effects. The course will be beneficial for Mechanical Engineering students.

GATE (Graduate Aptitude Test in Engineering) 2020 & 2021 complete preparation with best educators. Know about the detailed syllabus, best books, exam pattern and dates, previous year question papers a

GATE - Iconic Pro

English

Complex Flow Motions of Molten Metal During Welding

Metal Casting

Manufacturing Engineering

Mechanical Engineering

GATE & ESE - ME & CH

GATE, ESE and IIT-JAM

Ace the toughest competitive and government exams in India 

Test Preparation

The hydrodynamics of the molten metal in weld pools is quite complex and often the flow is highly unstable, as evidenced by large instabilities observed in the liquid surface.

Join our telegram group
💐 A.S.K.Azad Mechanical Engineering (pot of knowledge)
https://t.me/ASKAzadMechanicalEngineering

You can watch my more detail video on my
YouTube channel "A.S.K.Azad Mechanical Engineering"

https://goo.gl/cZvFfF

Introduction, Literature Review, Need and Applications

Outward flow patterns with time step 12ms between two successive images, and last image shows flow direction.

Inward flow patterns with time step 2ms between two successive images

Experimental system, Macro Fluid Motions and Oscillation flow

How oxygen component, temperature can influence the surface tension?

The contact line between liquid and solid on the sample surface play an important job to balance the surface energy.

We observed some novel instability phenomena.

Theoretical analysis,Thermal instability, Spreading and wetting

Laser Beam Welding involves interaction of high intensity (Φ = 104 – 107 W/cm2) laser with structural metals and alloys.

Such interactions generate non-stationary motions and instabilities in the melt pool.

Other notable non-stationary hydro and gas dynamic phenomena are bulk and near surface turbulent flows of liquid – vapour – gas, large scale ( 0.1 cm to 1 cm) and small scale instabilities on liquid surface (~10-4 –10-2 cm) involving multiphase flow.

Hydrodynamic Phenomena during Laser Welding

Laser welding is usually categorized into two different modes; 
    a. conduction welding with a low power density, and 
    b. keyhole welding, where a high power density evaporates a     	deep cavity or ‘keyhole’ in the material.

The main goal of this section is to present quantitative measurements of the downward flow on the keyhole front.

The increase in downward flow with increasing laser power resulted in the well-known phenomenon of humping.

Melt Flow Measurement Inside The Keyhole During Laser Welding

After capturing a high speed video of 4000 frames, the velocity of flow in the video was calculated using a streak photo technique 

The vertical axis of the streak image represents distance travelled down the keyhole front – from top to bottom.

The horizontal axis of the streak image represents time.

So a bright dot moving down the keyhole front looks like an inclined line on the streak image – and the closer to vertical the steak is, the faster the dot was moving.

Streak Image Technique & Fourier Transform Analysis

Parameter influence on downward flow.

The results from the 2d-FFT velocity estimation of a wide range of welds are shown in Fig.

The most dominant velocity* is presented in the graphs,

but it is interesting to note that the maximum downwards velocity in the streak images was estimated to be as high as 25m/s for 15kW laser power.

Results 1

Welds with constant line energy

A longitudinal section along the weld produced with 9kW laser power showed a sinusoidal weld depth variation. 

The weld depth varied between 1,65mm and 1,9mm. The length of the period was 4,6mm, and was almost constant for the 8m/min and 10m/min welding speeds. 

As soon as the welding process is in the humping regime, large undercuts are created. 

And the characteristic periodic humps are building up along the centre of the weld.

Results 2

Flow dynamics phenomena in the weld pool are complex and could be affected by many factors,

at high energy density input during laser welding with heat conduction model,

the surface tension play main role, and

the surface tension gradient is influenced by surface active.

Discussion & Conclusion

Telegram Group for all Students and Teachers (Pot of Knowledge)
https://t.me/ASKAzadMechanicalEngineering

A S K Azad Mechanical Engineering

In this course, Abhinandan will be discussing Rolling, Hot & Cold Rolling, Ring Rolling, Sheet Rolling, Roll Bending, Shape Rolling, Pack Rolling, Thread Rolling, Manufacturing of Gears by Rolling, Roll Piercing, Planetary Mill, Camber, Defects in Rolling, Draft, Roll Strio Contact Length, Number of Pass Needed, Elongation Factor, Force, Torque and Power.

(Hindi) Production 7: Rolling

Graduated in Mechanical Engineering. 
Working as Quality Control Executive in BHEL.
Likes to Play Football & Passionate for Teaching.

Harish Patidar

It is about the welding techniques, Terminologies, different welding types and Problems on Welding for GATE.

Welding Process for GATE

I am a Mechanical Engineer.i have working experience in production,project planning and quality control. UPSC Aspirant

Manish Kumar

This course will help you learn more about welding technology.

(Hindi) Welding Process - Part 1

ies prelims cleared
gate 2018 cleared
gate 2019 cleared
4 year teaching experience



Ravindra Lakhara

This course contains all the topics and questions generally asked in competition examination, simple student oriented approach to solve all the student oriented queries. simple tricks to remember more data for students.

(Hindi) Complete Course on Production Engineering, Casting, Forming, Important: GATE

B.E. (MECHANICAL ENGINEERING) in 2016 CLEARED GATE 3 TIMES . UPSC-CSE And State Exams Aspirant .

Deepak Gupta

This course contains various types of the welding process and their application with basics of the welding process.

(Hindi) Basics of Welding Process: Mechanical Engineering

Mohd Imran

This Course covers Dof, Velocity and Acceleration for ESE.

Lessons

9 lessons • 1h 28m

Invalid Date

NaN

Introduction, Literature Review, Need and Applications

Invalid Date

NaN

Experimental system, Macro Fluid Motions and Oscillation flow

Invalid Date

NaN

Theoretical analysis,Thermal instability, Spreading and wetting

Invalid Date

NaN

Hydrodynamic Phenomena during Laser Welding

Invalid Date

NaN

Melt Flow Measurement Inside The Keyhole During Laser Welding

Invalid Date

NaN

Streak Image Technique & Fourier Transform Analysis

Invalid Date

NaN

Results 1

Invalid Date

NaN

Results 2

Invalid Date

NaN

Discussion & Conclusion