PROJECT TITLE:
“STUDY OF HYBRID FUSION WELDING ON MILD STEEL”
PRESENTED BY:RAVISHANKAR KUMAR RAI (8TH SEMESTERMECHANICAL ENGG. DEPT )
INTRODUCTION
Welding is one of the versatile joining processes.
There are different ways to weld, such as: Arc welding, Gas welding, Resistance
welding, solid State welding and other processes
Different energy sources can be used for welding including a gas flame, an
electric arc, laser, an electron beam, friction, and ultrasound.
Fig:- types of weld joint
CLASSIFICATION OF WELDING
PROCESS:
Gas welding
Arc welding
Resistance welding
Solid state welding
Other welding process
In our work we concentrate on arc welding. We have tried to
study the properties obtained When we do hybrid welding by
combining MIG and SAW.
ARC WELDING Arc welding uses a welding power supply to create an electric arc between an
electrode and the base material to melt the metals at the welding point.
current source can be direct (DC) or alternating(AC) current, and consumable or non-
consumable electrodes
An arc is created across the gap when the energized circuit and the electrode tip
touches the work piece and is withdrawn, yet still with in close contact.
The arc produces a temperature of about 6500ºF at the tip. This heat melts both the
base metal and the electrode, producing a pool of molten metal sometimes called a
"crater”.
Many arc-welding processes provide some means of covering the arc and the molten
pool with a protective shield of gas, vapor, or slag. This is called arc shielding. This
shielding prevents or minimizes contact of the molten metal with air. Shielding also
may improve the weld. An example is a granular flux, which actually adds deoxidizers
to the weld.
Arrangement of different equipments in an arc welding setup:
General steps in welding:
MIG (Metal inert gas) welding : It is an arc welding process, in which
the weld is shielded by an external
gas (Argon, helium, CO2, argon
+ Oxygen or other gas mixtures).
Consumable electrode wire, having
chemical composition similar to that
of the parent material, is
continuously fed from a spool to
the arc zone.
The arc heats and melts both the
work pieces edges and the electrode
wire.
Due to automatic feeding of the
filling wire (electrode) the process is
referred to as a semi-automatic. The
operator controls only the torch
positioning and speed.
Continued:
ADVANTAGES OF MIG:• Continuous weld may be produced (no interruptions);
• High level of operators skill is not required;
• Slag removal is not required (no slag);
DISADVANTAGES OF MIG WELDING:• Expensive and non-portable equipment is required;
• Outdoor application are limited because of effect of wind, dispersing the shielding
gas.
SAW (SUBMERGED ARC WELDING) :
• Submerged Arc Welding is a welding process, which utilizes a bare consumable metallic electrode producing an arc between itself and the work piece within a granular shielding flux applied around the weld.
ADVANTAGES OF SAW :
Very high welding rate;
The process is suitable for automation;
High quality weld structure.
DISADVANTAGES OF SAW :
Weld may contain slag inclusions;
Limited applications of the process - mostly for welding horizontally located
plates.
Since the electrode is submerged into the flux, the arc is invisible. The flux is
partially melts and forms a slag protecting the weld pool from oxidation and
other atmospheric contaminations
Continued :
HYBRID WELDING PROCESSES :
(a) Hybrid laser arc welding (b) Industrial application of hybrid laser arc
welding.
Experimentation:
Experimental work required for fulfillment of the objectives was
performed at the Workshop of National Institute of Technology, Agartala. The
facilities that will be used during experimentation are:-
Arc welding process setup(MIG AND SAW)
Polishing machine
hardness testing machine
Optical microscope
Material specifications:
Material used: Mild steel plate of size (200mm×50mm×16.5mm)
Designation: IS 2062 grade B, SAIL steel
Application: IS 2062, Grade B material is mostly used for fabrication of heavy-duty
products such as ship building, bridge, railway wagon, automotive, construction etc.
Chemical composition of work piece:-
GRADE C% Mn% P% S% Si% C.E%
Max Max Max Max Max Max
B 0.22 1.5 0.045 0.045 0.04 0.41
Process Parameters for MIG and SAW Processes:
Voltage Current Travel speed Wire feed Stick out
MIG 29.2 102 manual automatic 30 mm(approx)
SAW 35 v automatic 60mm/min 4m/min 29mm
Outline of the work:
The first phase consist of brief study of SAW and MIG weldingprocesses.
The second phase involves the literature review of previousresearch work in domain of submerged arc welding process andmetal inert gas welding process to recognize the objective of presentwork.
After deciding the objective of the present work trial based
experimentation is done on a sample of mild steel of above mentioned
specification.
Phase four consist of actual data collection such as bead width,
reinforcement, depth of penetration and hardness.
Fifth phase involves the visualization of micro structural changes.
Sixth phase accomplishes with the data analysis and writing work.
Data collection procedure:
After removing the solidified slag, the weld sample has been cooled in
ambient condition.
Three cross sections of the sample of about 5mm of thickness have been
cut by power hydraulic saw with normal water as coolant. The three
sections are respectively MIG weld portion, MIG + SAW Weld portion
and SAW Weld portion.
The section faces of each sample have been machined by shaper to get
semi-finished surface. Then samples have been filed with smooth flat file
followed by finishing with the emery paper of grade 120, 220, 400, 600,
1000, and 2000 consequently getting almost mirror finish.
The mirror finished surfaces have been etched with natal solution i.e.
10% nitric acid solution in distilled water in room atmospheric condition.
The weld bead geometry attributes such as bead width, depth of
penetration, haz width and reinforcement have been measured with
Digital Vernier Calliper.
Machine setups:
Fig 1: Submerged Arc Welding Set up Fig 2: MIG/MAG machine setup
Results:
After the successive tests following results are obtained relating to
various attributes of weld bead such as depth of penetration, bead width,
reinforcement, haz width measured with the help of vernier caliper. Hardness
testing using the vickers hardness testing machine and the micro structure study
of the obtained weld bead is yet to be done.
Fig6:- Specimen formed on combination of MIG+SAW, bead on plate.
Fig: Cross section of sample of combined SAW welded portion
Fig: Cross section of sample of combined MIG
welded portion
Fig: Cross section of sample of combined MIG and SAW
welded portion
Table 1.1: Measured experimental data related to bead geometry:-
SAMPLE NO. HAZ WIDTH BEAD WIDTH PENETRATIO
N
REINFORCEM
ENT
1(MIG) .96 7.48 3.22 2.88
2(MIG+SAW) 1.96 11.89 3.96 4.76
3(SAW) 2.03 12.20 5.54 3.73
Fig8:- Weld specimen(schematic) representing the points of hardness testing
MEASUREMENTS TO BE DONE FURTHER :
MICRO HARDNESS TEST USING VICKERS HARDNESS TESTING
MACHINE
THE RESULTS OBTAINED WILL BE PLOTTED GRAPHICALLY AND IN TABULAR FORMS:
POINTS SAMPLE 1
(MIG)
SAMPLE 2
(MIG+SAW)
SAMPLE 3
(SAW)
a
b
c
d
(a) For mig (b) for mig +saw (c) for saw
CONCLUSION:
After conducting of first phase of experimentation as pilot experiment the
following conclusions is furnished:
1.Size of the sample selected here is sufficient to study the present
investigation as the welding penetration depth as well as HAZ is within the
thickness of the sample and not crossing the plate.
2. From the table obtained for different bead geometry it can be said that the
HAZ, bead width and penetration are smaller in the case of hybrid MIG and
SAW welding.
REFERENCES: Coupling of Laser with Plasma Arc to Facilitate HybridWelding of Metallic
Materials: A Review (Submitted November 3, 2011; in revised form May
24, 2012; published online July 13, 2012 byLi Zhiyong, T.S. Srivatsan, LI Yan,
and Zhang Wenzha.
International Journal of Advances in Engineering Research
COMPARATIVE STUDY & ANALYSIS OF WELD STRENGTHS OF
SPOT & HYBRID LASER - MIG WELDING ON LAP JOINT (IJAER)
2012, Vol. No. 3, Issue No. VI, June ISSN: 2231-5152 21 by
Prof.Pushpendra Kumar Sharma1, Ravi Vishwakarma2, Prof. Sachin Jain3.
The effect of the relative location of laser beam with arc in different hybrid
welding processes ISSN 1392 - 1207. MECHANIKA. 2010. Nr.3(83) by P.
Kah, A. Salminen, J. Martikainen
LIU Li-ming, WANG Ji-feng, SONG Gang on Hybrid Laser-Arc Welding
of AZ31B Mg Alloy
THANK YOU…