Previous | Next | Contents ESDEP WG 3 FABRICATION AND ERECTION Lecture 3.4: Welding Processes OBJECTIVE/SCOPE To review the welding processes commonly used in construction and to highlight some practical considerations. PREREQUISITES Lectures 3.3: Principles of Welding SUMMARY This lecture describes the welding processes commonly used in construction: Manual Metal Arc Welding, Dip and Spray Transfer Metal Active Gas Welding, Submerged Arc Welding and Stud Welding. Each process is briefly described and its advantages, disadvantages and limitations of use are summarised. Choice of welding process for a particular situation is discussed. ABBREVIATIONS MAG Metal Active Gas Welding (sometimes referred to as MIG: Metal Inert Gas Welding) MMA Manual Metal Arc Welding SAW Submerged Arc Welding 1. INTRODUCTION - HEAT SOURCES AND METHODS OF SHIELDING There are three principal methods used to generate the heat required for welding: oxygen-acetylene flame. resistance to the passage of a current. electric arc. Each method produces a pool of molten steel which must be protected against atmospheric contamination. The method used to achieve this, i.e. the shielding technique, has a major influence on the characteristics of the process. For constructional steelwork, the processes used are usually based upon the electric arc. In arc welding, a flux or a non-reactive (inert) gas can be used to 'blanket' the weld pool and thus exclude air. This lecture is particularly concerned with the four arc welding processes commonly used in structural work. 2. MANUAL METAL ARC WELDING This manual method is one of the most widely used arc welding processes (see Figure 1). It requires considerable skill to produce good quality welds. The electrode consists of a steel core wire and a covering flux containing alloying ESDEP LECTURE NOTE [WG3] http://www.fgg.uni-lj.si/kmk/esdep/master/wg03/l0400.htm 1 of 12 2/1/2013 11:08 PM
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ESDEP WG 3
FABRICATION AND ERECTION
Lecture 3.4: Welding Processes
OBJECTIVE/SCOPE
To review the welding processes commonly used in construction and to highlight some practical considerations.
PREREQUISITES
Lectures 3.3: Principles of Welding
SUMMARY
This lecture describes the welding processes commonly used in construction: Manual Metal Arc Welding, Dip and
Spray Transfer Metal Active Gas Welding, Submerged Arc Welding and Stud Welding. Each process is briefly
described and its advantages, disadvantages and limitations of use are summarised. Choice of welding process for a
particular situation is discussed.
ABBREVIATIONS
MAG Metal Active Gas Welding (sometimes referred to as MIG: Metal Inert Gas Welding)
MMA Manual Metal Arc Welding
SAW Submerged Arc Welding
1. INTRODUCTION - HEAT SOURCES AND METHODS OF
SHIELDING
There are three principal methods used to generate the heat required for welding:
oxygen-acetylene flame.
resistance to the passage of a current.
electric arc.
Each method produces a pool of molten steel which must be protected against atmospheric contamination. The
method used to achieve this, i.e. the shielding technique, has a major influence on the characteristics of the process.
For constructional steelwork, the processes used are usually based upon the electric arc.
In arc welding, a flux or a non-reactive (inert) gas can be used to 'blanket' the weld pool and thus exclude air. This
lecture is particularly concerned with the four arc welding processes commonly used in structural work.
2. MANUAL METAL ARC WELDING
This manual method is one of the most widely used arc welding processes (see Figure 1). It requires considerable skill
to produce good quality welds. The electrode consists of a steel core wire and a covering flux containing alloying