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touches the work piece and is withdrawn, yet still with in close contact.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…