welding expertiseFrequently asked questions and answers give enormous knowledge power to face challenges and better understanding.
A)Welding processes-Knowledge power for solutions
Welding Knowledge power on welding processes is key for success in fabrication.
1.What are the examples for homogenous welding.
SMAW,GTAW,GMAW,SAW,EGW,ESW with matching filler addition.
2.Why TIG welding is preferred for good quality welds.
Aero space applications require
Zero defect and use Titanium alloys and aluminium alloys. TIG
welding with extra purity Argon shielding provides highly reliable joints.
3.Why synnergic MIG is useful .
Thin sheet welding in critical applications can be welded without the problem of burn through.
4.what are the methods to control arc blow in DC welding.
a. Make sure the ground is properly located on the work. Placing the ground in the direction of the arc deflection is helpful.
b. Separating the ground into two or more parts is helpful.
c. Weld towards the direction in which the arc blows.
d.Maintain a short arc.
e. Changing the angle of the electrode relative to the work may help to control the arc.
f. Magnetic blow is minimum in alternating current welding.
5.Which automatic processes are employed for welding plates in vertical direction
Electro slag and electro gas processes can be used for vertical welding of plates.Ship building ,storage tanks,and pressure vessels find good use.
6.Why SAW is preferred for thick plates in flat position.
Multi layer welds in thick plates give better toughness due to grain refinement of previous layer by subsequent layer.
7.Which shielding gas is used with MIG for stainless steels when using DC +
Argon +1%oxygen to eliminate undercutting
8.When argon+5% oxygen is used for stainless steel MIG
For Dc – ve welding to improve arc stability.
9. Why GMAW with carbon dioxide requires deoxidisers in wire such as.
Si,Mn,Ti,V react with oxygen and protect weldmetal to improve quality
10.Which gas mixture gives best quality welds with flux cored arc welding
75% argon +25% carbon dioxide
11.What is the maximum inter pass temperature for carbon steel submerged arc welds.
260 deg.C
12.When basic fluxes are used.
Basicity has great influence on impact toughness of the weld metal. Increasing basicity brings down the oxygen content and hence the inclusion level in the weld metal. Consequently, the impact toughness will increase and also, to a limited extent, the ductility of the weld metal.
The relation between basicity and impact toughness is particularly important for high alloyed grades, such as duplex steels.
13.Which process can be used for inconel overlaying of tube sheet for nuclear steam generator.
Submerged arc strip cladding process can be used with wide strip.Electroslag strip cladding process also is another method.
14.What is the best process for managing steel welding required for aero space applications.
GTAW with continuous wire addition can be used with special purpose
system.
15.Which process is good for pipeline welding of large diameters for various medium applications.
Orbital GMAW special purpose welding equipment finds great use with higher productivity
16.What process is ideal for welding very large thicknesses .
Narrow gap submerged arc welding with special J type edge preparation provides less weld metal and better impact strength.Grain refinement takes place by the subsequent passes in multi layer welding.
17.Which electrode gives good deposition rate and quality welds for low carbon steels.
E7018 is ideally suited for improving productivity and avoiding cold cracking tendency.
18.Which electrode gives better performance for welding austenitic stainless steel and low carbon steel.
E309 electrode is good for crack free welds.
19.Where is sodium titanate used.
Electrode coatings use for good quality and arc stability.
20.What is the use of cellulose coated electrodes.
Deep penetration electrode used for structural fabrication,pipes and repair works.
21.Which electrodes are suitable for flat and horizontal welding positions.
E 6020,E6027,E 7024,E7027,E7028 are suitable .
22.Which electrode is preferred for welding low carbon steel to austenitic stainless steel.
E 309 is compatable to both metals.