Influence of Welding Parameters On Grain Size, Haz and Degree of Dilution in 6063-t5 Alloy. Optimisation Through the Taguchi Method of the Gmaw Welding Process.

The aim of this work is to carry out the design of experiments that determine the influence of the welding parameters using Taguchi’s method on the grain size, HAZ, and the degree of dilution in 6063-T5 alloy. The welding process used is GMAW and the welding parameters are power, welding speed and bevel spacing. The study of the influence of the welding parameters on the measurements made in the welding (which are the size of heat affected zone, the degree of dilution, and the grain size) allows one to determine the quality of the joint . In addition, the welding parameter most influential in minimising the three measurements will be determined.

Effect of Temperature Variation of Static Thermal Tensioning on Angular Distortion and Sensitization behavior of GMAW Welded SUS 304 Stainless Steel Plate

Due to its rust resistance properties, the use of stainless steels, especially SUS304 for industrial equipment is increasing. The manufacturing process that is often used is GMAW welding. One of the disadvantages of SUS304 is the occurrence of distortion and sensitization when welded. In this study, the effect of temperature variations of Static Thermal Tensioning on angle distortion and microstructure behavior due to GMAW welding of SUS 304 T-joint plates was studied. Heating by electric heater is given to both parts of the base metal plate SUS 304 5mm thick with temperature variations of 200 oC, 250 oC and 300 oC. Cooling water with a temperature of 24 oC is provided on the back side of the welded track. Welding using filler ER 304 with a diameter of 0.8 mm with welding parameters such as welding current, voltage, gas flow and travel speed controlled at 75 A, 22 V, 10 l/min and 8 mm/s, respectively. Angular distortion of welding results for each treatment temperature variation was measured using a bevel protractor, and perform metallographic test to knowing the microstructural behavior. The results of the measurement of the average angular distortion of three repetitions show that at a temperature of 250 C static thermal tensioning produces the smallest angular distortion of 3ᵒ70', compared to other temperature variations which produce angular distortion 4o45’ at 200 oC and 3o86' at temperature 300 oC. The findings of the largest Cr (carbide) deposits due to sensitization were found at a temperature of 300 oC at 16,49% and the lowest at a temperature of 200 oC at 7,05%

Effect of Heat Input on the Ballistic Performance of Armor Steel Weldments

The purpose of this study is to examine the projectile penetration resistance of the base metal and heat-affected zones of armor steel weldments. To ensure the proper quality of armor steel welded joints and associated ballistic protection, it is important to find the optimum heat input for armor steel welding. A total of two armor steel weldments made at heat inputs of 1.29 kJ/mm and 1.55 kJ/mm were tested for ballistic protection performance. The GMAW welding carried out employing a robot-controlled process. Owing to a higher ballistic limit, the heat-affected zone (HAZ) of the 1.29 kJ/mm weldment was found to be more resistant to projectile penetration than that of the 1.55 kJ/mm weldment. The ballistic performance of the weldments was determined by analyzing the microstructure of weldment heat-affected zones, the hardness gradients across the weldments and the thermal history of the welding heat inputs considered. The result showed that the ballistic resistance of heat affected zone exist as the heat input was decreased on 1.29 kJ/mm. It was found that 1.55 kJ/mm does not have ballistic resistance.

Pengaruh Variasi Colling pada Pengelasan GMAW Terhadap Uji Tarik dan Uji Kekerasan pada Baja ST 60

The technology of the manufacturing industry is developing rapidly, where the rapid development of this technology cannot be separated from the welding field. In the welding process, thermal heat is used until the material melts, the heat change will also cause changes in the structure, stress and also deformation of the material. This is because the more carbon elements are captured, the more martyred structures are formed. This causes an increase in the value of hardness and tensile strength values in the material. The purpose of this study was to determine the effect of the temperature of the cooling medium oil, salt water, water. dromus, and free air in GMAW welding on the tensile test of ST 60 steel. To determine the effect of cooling temperature medium of Oil, Salt Water, Dromus Water, and Free Air on GMAW welding toward the tensile test and hardness test of ST 60 steel. Several means used for testing are calculating the tensile stress Mpa and HVN hardness. This research method used the experimental method. The GMAW welding process variations of coolant were used, such as oil, salt water, dromus water, and free air with a time of 25 minutes and electic current of 100 A. The type of seam used was a V type with angle of 30o. The tests carried out were tensile and hardness test. The highest average value of the tensile stress from the the salt water coolant specimen was 490.23 Mpa. The highest average value of the tensile strain from free air specimens was 35.45 Mpa. The average value of HVN hardness from Oil specimens was 208.3 HVN, salt water was 231.0 HVN, Dromus water was 215.5 HVN, and free air was 228.0 HVN. From the average value of HVN hardness, the highest value observed was the salt water specimen with 231.0 HVN.

Influence of the CO2 Content in Shielding Gas on the Temperature of the Shielding Gas Nozzle during GMAW Welding

Gas metal arc welding torches are commonly chosen based on their current-carrying capacity. It is known that the current-carrying capacity of welding torches under CO2 is usually higher than under argon dominated shielding gases. In this publication, the extent to which this can be attributed to the shielding gas dependent arc radiation is investigated. For this purpose, the influence of the shielding gas on the thermal load of the shielding gas nozzle of a GMAW torch was calorimetrically measured. These experiments were carried out for four different shielding gases (argon, CO2, and two argon/CO2 mixtures). The measurements were all performed at an average current of 300 A. The welding current was set by adjusting the wire feed rate or the voltage correction. For each case, a separate set of experiments was done. It is shown that the changed arc radiation resulting from the different shielding gases has an influence on the heat input into the gas nozzle, and thus into the torch. For the same shielding gas, this influence largely correlates with the welding voltage.

Stainless Steel Pipe Welding With No Backing Gas

For pipe fabrication shops, stainless steel pipe welding typically represents 15%–20% of their business. The pipe materials fabricated in these shops are primarily austenitic stainless 304L and 316L pipe. The quality requirements in stainless pipe fabrication shops are determined by performance requirements for service applications in low temperature, high temperature or corrosive environments. To enable the performance required in these applications, codes, standards and recommended practices for welding are frequently written from a conventional GTAW or SMAW welding paradigm. In addition, for the root pass and the first fill pass made with GTAW, an inert backing gas is always recommended to minimize or eliminate the discoloration or oxidation on the ID surface of the pipe near the root pass. The use of GTAW with inert backing gas adds significant time, complexity and cost to the welding of stainless pipe. In stainless pipe shop fabrication, very few welding practices recognize or encourage the use of GMAW welding solutions for these applications, even though it is known to be a more productive and economical welding process. Moreover, the absence of a consistent and proven GMAW welding solution in terms of either no backing gas GMAW, alternative options for expensive shielding gases, implementing unique welding waveforms etc., proves to be a hindrance in the adoption of GMAW solutions for the welding of stainless pipe. In this paper, we discuss advances that have been made in producing acceptable stainless pipe welds with a 1G GMAW welding solution using an STT® waveform for the root pass and a unique “Rapid X™” waveform for fill passes with no use of backing gas. One goal of this project was to also find a shielding gas mixture to provide acceptable welds from root to cap that takes into account both welding process performance as well as fabrication of defect free welds. Six different shielding gas mixtures with varying amounts of Ar, He, CO2 and N2 were evaluated. Results indicate that STT/RAPID X™ welds made with 97%Ar/2%CO2/1%H2 provide very promising results in terms of weld appearance and other conventional metrics such as radiography, bends and tensile properties. However, assessment of the corrosion performance in comparison to welds made with conventional GTAW requires development of a better test protocol than the ASTM G48 Method A test for it to be relevant and meaningful.