Weldability of High-Mn Austenitic Twinning-Induced Plasticity (TWIP) Steel Microalloyed with Nb

MRS Advances ◽  
2017 ◽  
Vol 2 (62) ◽  
pp. 3899-3908 ◽  
Author(s):  
I. Mejía ◽  
H. Hernández-Belmontes ◽  
C. Maldonado
Keyword(s):  
Heat Affected Zone ◽  
Twip Steel ◽  
Research Work ◽  
Welding Process ◽  
X Ray Diffraction ◽  
Austenite Stability ◽  
Gas Tungsten Arc ◽  
Solution Condition ◽  
Gtaw Process ◽  
Arc Welding Process

ABSTRACTThe objective of this research work is to study the weldability of a Nb microalloyed TWIP steel through welding nuggets generated by Gas Tungsten Arc Welding process. Weldability was examined by microstructural changes in the fusion zone (FZ) and heat affected zone (HAZ) using light optical metallography (LOM), segregation in the nuggets was evaluated using elemental mappings of chemical analysis by Scanning Electron Microscopy and Electron Dispersive Spectroscopy (SEM-EDS), phase transformations were evaluated using X-ray diffraction (XRD) and the hardness properties were examined using Vickers microhardness testing (HV25). Experimental results show that microstructure of welding nuggets consists of austenitic dendritic grains in the FZ and equiaxed grains in the HAZ. FZ width and HAZ grain growth tend to increase as the heat input increases. Additionally, the studied Nb-containing TWIP steel showed segregation in the FZ, where Mn and Si segregated in the interdendritic regions, while Al and C preferentially segregated in dendritic areas. In general, the data obtained by XRD indicated that GTAW process did not affect austenite stability. Finally, the welding nuggets of studied TWIP steel showed lower microhardness values than the as-solution condition (starting condition). However, the heat affected zone showed hardened areas, which are associated with NbC precipitation hardening.

Distortion control in multi pass dissimilar GTAW process using Taguchi ANOVA analysis

2018 ◽  
Vol 7 (3) ◽  
pp. 1140 ◽  
Author(s):  
Harinadh Vemanaboina ◽  
G Edison ◽  
Suresh Akella
Keyword(s):  
Welding Process ◽  
Fractional Factorial ◽  
Inconel 625 ◽  
Filler Wire ◽  
Gas Tungsten Arc ◽  
Distortion Control ◽  
Gtaw Process ◽  
Continuous Current ◽  
Arc Welding Process

The present study is to observe the distortion development in the weldment of Inconel 625 to SS316L multipass weldments. In this work two-level factors such as welding process, filler wire and root gap were employed with L4 orthogonal array. The welding has been carried out with continuous current and pulsed current gas tungsten arc welding process implementing ERNiCrMo-3 and ERNiCr-3 fillers rods respectively. The fractional factorial experimentation was analysis of variances (ANOVA), it was carried out to observe the critical parame-ter which influence distortion caused in the weldments. The quality of welds has been evaluated by X-Ray Radiography test. The results show that welding process and filler wire are contributing more in the distortion.  

Influence of Thermal Simulated and Real Tandem Submerged Arc Welding Process on the Microstructure and Mechanical Properties of the Coarse Grained Heat Affected Zone

2011 ◽  
Vol 110-116 ◽  
pp. 3191-3198
Author(s):  
Sadegh Moeinifar
Keyword(s):  
Grain Boundaries ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Rolled Plate ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Tandem Submerged Arc Welding

The high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The Gleeble thermal simulated process involved heating the steel specimens to the peak temperature of 1400 °C, with constant cooling rates of 3.75 °C/s and 2 °C/s to room temperature. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone regions. The martensite/austenite constituents were obtained by a combination of field emission scanning electron microscopes and image analysis software The Charpy absorbed energy of specimens was assessed using Charpy impact testing at-50 °C. Brittle particles, such as martensite/austenite constituent along the grain boundaries, can make an easy path for crack propagation. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.

Heat Input Effect on the Microstructure of Twinning-Induced Plasticity (TWIP) Steel Welded Joints Through the GTAW Process

MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3949-3956
Author(s):  
H. Hernández-Belmontes ◽  
I. Mejía ◽  
V. García-García ◽  
C. Maldonado
Keyword(s):  
Phase Transformations ◽  
Heat Input ◽  
Twip Steel ◽  
Research Work ◽  
Second Phase ◽  
Current Electrode ◽  
Weld Joints ◽  
Average Grain Size ◽  
Gtaw Process ◽  
Twip Steels

ABSTRACTHigh-Mn Twinning Induced Plasticity (TWIP) steels are an excellent alternative in the design of structural components for the automotive industry. The TWIP steels application allows weight reduction, maintaining the performance of vehicles. Nowadays the research works focused on TWIP steel weldability are relative scarce. It is well-known that weldability is one of the main limitations for industrial application of TWIP steel. The main goal of this research work was studied the effect of heat input on the microstructural changes generated in a TWIP steel microalloyed with Ti. A pair of welds were performed through Gas Tungsten Arc Welding (GTAW) process. The GTAW process was carried out without filler material, using Direc Current Electrode Negative (DCEN), tungsten electrode EWTh-2 and Ar as shielding gas. The microstructure and average grain size in the fusion (FZ) and heat affected zone (HAZ) were determined by light optical metallography (LOM). Elements segregation in the FZ was evaluated using point and elemental mapping chemical analysis (EPMA) by Scanning Electron Microscopy and Electron Dispersive Spectroscopy (SEM-EDS). Phase transformations were evaluated using X-ray diffraction (XRD). Finally, the hardness were measured by means of Vickers microhardness testing (HV500). The results show that the FZ is characterized by a dendritic solidification pattern. Meanwhile, the HAZ presented equiaxed grains in both weld joints. On the other hand, the TWIP-Ti steel weldments did not present austenite phase transformations. Nevertheless, the FZ exhibited variations in the chemical elements distribution (Mn, Al, Si and C), which were higher as the heat input increases. Finally, the heat input reduced the microhardness of TWIP-Ti steel weld joints. Although post-welding hardness recovery was detected, which is associated with precipitation of Ti second-phase particles.

A Neural Network Model for Predicting Two Observable Parameters of the Welded Cross Section in Case of Robotic Gas Tungsten Arc Welding Process

2012 ◽  
Vol 162 ◽  
pp. 531-536
Author(s):  
Gabriel Gorghiu ◽  
Paul Ciprian Patic ◽  
Dorin Cârstoiu
Keyword(s):  
Neural Network ◽  
Arc Welding ◽  
Welding Process ◽  
Gas Tungsten Arc Welding ◽  
Gas Tungsten Arc ◽  
Proposed Model ◽  
Input Layer ◽  
Gas Tungsten ◽  
Arc Welding Process ◽  
Observable Parameter

The paper presents a model of using the artificial neural networks when determining the relations of dependency between the observable parameters and the controllable ones in the case of RoboticGas Tungsten Arc Welding. The proposed model is based on the direct observation of welded joints, emphasizing on the process variables which have been arranged in the nodes of a neural network. The design of the network intended to achieve an architecture that contains four nodes in the input layer (all of them being controllable parameters) and two nodes in the output layer (one for each observable parameter).

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