Influence of cold-wire tandem submerged arc welding parameters on weld geometry and microhardness of microalloyed pipeline steels

Abstract

Tandem submerged arc welding with an additional cold-wire (CWTSAW) is being developed for pipeline manufacturing to improve productivity in terms of deposition rate and travel speed of welding. An appropriate understanding of the welding conditions to guarantee requisite weld geometry, appearance, and mechanical properties is always essential in the development of a welding process. Currently, the effect of the cold-wire addition parameters on dilution and the geometry and properties of the weld metal (WM) and the heataffected zone (HAZ) is not well understood. In this work, heat input, voltage, and travel speed of both electrodes along with three main cold-wire parameters are investigated and correlated with the geometry of the weld and HAZ, i.e., aspect ratio (AR), semi-penetration ratio (SPR), reinforcement area (RA), and coarse-grained heat-affected zone (CGHAZ) area, dilution, and the microhardness of the WM and CGHAZ. The results showed that varying the cold-wire parameters significantly affects the dilution, AR, SPR, and microhardness. The addition of a cold-wire at a lagging position with a feed speed of 8.5 mm/s at 63°resulted in an overall improvement in the weld geometry, dilution, and microhardness. Cold-wire addition led to a reduction in the CGHAZ area, the amount of dilution, and the microhardness of the CGHAZ. Microstructural analysis, using both optical microscopy and scanning electron microscopy (SEM), indicated the formation of finer prior austenite grains (PAGs) and less martensiteaustenite (M-A) constituent within the CGHAZ of the CWTSAW samples. The appropriate process parameters are defined to control the weld and HAZ geometry, dilution, and mechanical properties.

Avaliação do Uso do Tecimento na Soldagem a Arco Submerso

“…74/82 de arame adicional na modalidade "cold-wire" [7][8][9] ou "hot-wire" [10], e a soldagem com um prolongador [11][12][13] com o intuito de aumentar o stickout e, assim, aproveitar o aquecimento produzido por efeito joule devido à passagem da corrente de soldagem.…”

Parametric study of cold wire tandem submerged arc welding of heavy gauge X70 linepipe steel

“…The nominal heat input (HI) and voltage (V) are key welding parameters and the current was calculated and set during welding according to Eq. 1 [7].…”

“…Consequently, the quality of weldments, such as toughness and microstructure, may deteriorate [4,5]. To increase productivity while maintaining the quality of TSAW pipeline products, cold wire tandem submerged arc welding (CWTSAW) was developed [6,7].…”

“…This method was rst developed by Mruczek et al [6] in the SAW process for enhancing welding capabilities and improving weld productivity by increasing deposition rate. Mohammadijoo et al [7] applied cold wire addition to the TSAW process of an intermediate thickness X70 line pipe (13.4 mm). The cold wire was placed at a lagging position next to the trailing electrode where it consumed heat from the weld pool.…”

“…Sarkar et al [13] employed Taguchi techniques to analyze the effective contribution of bead geometry on tensile strength and validated the results with con rmatory tests in the SAW process. In addition, Mohammadijoo et al [7] employed the Taguchi method to optimize the CWTSAW process of intermediate gauge X70 steels by de ning signi cant welding parameters and suitable levels of process parameters.…”