Profile Map of Weld Beads and Its Formation Mechanism in Gas Metal Arc Welding

Abstract

In order to investigate the profile map of weld beads and its formation mechanism in gas metal arc welding (GMAW), bead-on-plate welding was carried out with different average currents, and the dimensions of a weld bead were measured. The results show that the profile of weld beads can be divided into three stages according to the volume relationship between the melted filler metal and the weld pool. During the stages, the top surface of the reinforcement consisting of the central plane and the side plane mainly goes through inversed-U, W, V, and U shapes, which are mainly attributed to the change of flow pattern. Moreover, the role played by the bottom wall in determining the flow pattern and the resultant bead profile has been investigated as well. The experiment results show that with the bottom wall changing from the solid to the totally melted state, the role of redirecting, redistributing and bearing the molten metal played by the bottom wall gradually disappears. As a result, the side reinforcement is no longer covered by the liquid flowing backward. The top reinforcement is thoroughly collapsed when the width of the bottom reinforcement exceeds that of the top one by 1.1 mm.

Modeling and optimization of weld bead profile with varied welding stages for weathering steel A606

“…This behavior seems to be against Chandrasekaran's research work [15]. According to Zhang et al [14], the melting speed of base metal is less than that of filler wire when the welding current is at its lower level; in this case, more molten filler wire is deposited on the surface of the welding pool, which makes up of the reinforcement. As the welding current gets larger, the melting rate of the base metal is faster than that of the feeding wire; in this case, the welding pool can accommodate more melted feeding wire, which in turn gives rise to less melted feeding wire overflowing the welding pool.…”

“…Throughout the welding process, the welding bead profile changes, and the final welding bead size determines the mechanical performance of the weld bead [13]. As stated by Zhang et al [14], the formation and stages of the welding bead with different welding process parameters include overflowing, matching, and inadequate. The welding bead profile changes from overflowing to inadequate as the welding heat input increases, the top reinforcement decreases while the bottom reinforcement increases from zero to a certain value simultaneously.…”

Optimization and Influence of GMAW Parameters for Weld Geometrical and Mechanical Properties Using the Taguchi Method and Variance Analysis

“…Zhang and Xue [16] studied the weld bead and its formation mechanism. By the gas metal arc welding method, each test carried a different level of current and the weld profile was measured.…”

Study on Short-Circuiting GMAW Pool Behavior and Microstructure of the Weld with Different Waveform Control Methods

“…The weld geometry often qualifies melting characteristics of base metal, amount of weld deposition, welding heat input, energy distribution, and regulation of the flow of liquid metal to control its shape at various parameters [6]. The energy distribution and the metal transfer in the welding process depend on the waveforms of S-GMAW, which were both the main factors that affects the fluidity of the weld pool, and further affects the weld microstructure.…”

“…The other type is represented by Cold MIG (Metal-Inert Gas Welding) process [1] and Low Spatter The behavior of weld pool is a direct reaction of weld pool state, the dynamic variation of weld pool has a great influence on the weld bead shape and microstructure. Weld pool behavior may contain sufficient information to understand the mechanisms of welding bead formation and control the stability of welding process [5][6][7], so it is of great significance to study the weld pool behavior of S-GMAW using different waveforms.…”