scholarly journals Shielding gas effect on the structure of variable polarity GMA weldbrazed joints of galvanised sheets

2017 ◽  
Vol 62 (1) ◽  
pp. 91-98
Author(s):  
T. Pfeifer ◽  
A. Winiowski ◽  
J. Pikuła
Keyword(s):  
Partial Melting ◽  
Heat Input ◽  
Shielding Gases ◽  
Shielding Gas ◽  
Metallographic Examination ◽  
Variable Polarity ◽  
Gas Effect

Abstract The article presents the course and results of tests aimed to determine the effect of shielding gas on the shape of a weldbraze and on the structure of weldbrazed joints made of thin galvanised sheets. Test joints were made using innovative VP GMA weldbrazing utilising variable current and voltage waveforms. The tests involved the use of 3 types of shielding gases and mixtures, i.e. Ar, Ar + 1% O2 and Ar + 18% CO2, and required macro and microscopic metallographic examination of overlay brazes and weldbrazed joints. The tests conducted have revealed that the use of mixtures containing active gases, and CO2 in particular, increases the heat input of a weldbrazing process, improves the wettability of sheets and the geometry of weldbrazes, yet it also favours greater coat damage in the joining area and causes partial melting of workpieces.

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

2020 ◽  
Vol 4 (4) ◽  
pp. 113
Author(s):  
Martin Lohse ◽  
Marcus Trautmann ◽  
Uwe Füssel ◽  
Sascha Rose
Keyword(s):  
Carrying Capacity ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Shielding Gases ◽  
Shielding Gas ◽  
Metal Arc Welding ◽  
Average Current ◽  
Gas Nozzle ◽  
Wire Feed ◽  
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.

Influence of Argon-Nitrogen Gas to Balance the Microstructure in the Welding of Super Duplex Stainless Steel

2016 ◽  
Vol 836 ◽  
pp. 165-172
Author(s):  
Suheni
Keyword(s):  
Stainless Steel ◽  
Weld Metal ◽  
Duplex Stainless Steel ◽  
Heat Input ◽  
Oil And Gas ◽  
Austenite Phase ◽  
Super Duplex Stainless Steel ◽  
Shielding Gas ◽  
Input Variables ◽  
Protective Gas

Super duplex stainless steel is steel that has a corrosion resistance and good mechanical strength so that used in industry especially in oil and gas and petrochemical industry. In use in the field is often used for the connection process by welding methods. To produce good welds, it should be noted that the welding procedures and parameters used , especially the heat input. In this study is used the heat input variables shielding gas composition to determine how much influence on the balance of ferrite - austenite phase structure in the weld stainless steels SAF 2507 super duplex with tungsten inert gas welding method (TIG). Heat input varied by applying different welding speed 1,3,4 and 5 mm /sec while the shielding gas is used 100 % argon, 98 % argon + 2 % nitrogen and 95 % argon + 5 % nitrogen. The result showed that at different welding speeds generated depth and width of the weld metal which is different. Likewise the use of protective gas will produce a different ratio wide and deep of weld metal which is different. By using protective gas 95 % argon + 5 % nitrogen squeak - ausenit phase, resulting in weld metal that is relatively balanced than others. On a slow welding in addition to produce a large heat input also produces weld metal hardness at high and affect the growth of the austenite phase. The higher the heat input ( 2,280 kJ / mm ) , the lower the austenite phase in the weld metal.

SHIELDING GAS AND HEAT INPUT EFFECTS ON THE MECHANICAL AND METALLURGICAL CHARACTERIZATION OF GAS METAL ARC WELDING OF SUPER MARTENSITIC STAINLESS STEEL (12Cr5Ni2Mo) JOINTS

2016 ◽  
Vol 24 (05) ◽  
pp. 1750069
Author(s):  
T. PRABAKARAN ◽  
M. PRABHAKAR ◽  
P. SATHIYA
Keyword(s):  
Stainless Steel ◽  
Heat Input ◽  
Arc Welding ◽  
Martensitic Stainless Steel ◽  
Gas Metal Arc Welding ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Shielding Gas ◽  
Metal Arc Welding ◽  
Super Martensitic Stainless Steel

This paper deals with the effects of shielding gas mixtures (100% CO2, 100% Ar and 80 % Ar [Formula: see text] 20% CO[Formula: see text] and heat input (3.00, 3.65 and 4.33[Formula: see text]kJ/mm) on the mechanical and metallurgical characteristics of AISI 410[Formula: see text]S (American Iron and Steel Institute) super martensitic stainless steel (SMSS) by gas metal arc welding (GMAW) process. AISI 410[Formula: see text]S SMSS with 1.2[Formula: see text]mm diameter of a 410 filler wire was used in this study. A detailed microstructural analysis of the weld region as well as the mechanical properties (impact, microhardness and tensile tests at room temperature and 800[Formula: see text]C) was carried out. The tensile and impact fracture surfaces were further analyzed through scanning electron microscope (SEM). 100% Ar shielded welds have a higher amount of [Formula: see text] ferrite content and due to this fact the tensile strength of the joints is superior to the other two shielded welds.

scholarly journals SUVIRINIMO MEDŽIAGŲ ĮTAKOS KARŠTOJO CINKAVIMO PROCESO KOKYBEI TYRIMAS / THE ANALYSIS OF THE WELDING MATERIALS IMPACT FOR THE HOT-DIP GALVANIZATION PROCESS QUALITY

2019 ◽  
Vol 11 (0) ◽  
pp. 1-4
Author(s):  
Justė Rožėnė ◽  
Irmantas Gedzevičius ◽  
Šarūnas Mikaliūnas
Keyword(s):  
Corrosion Protection ◽  
Process Quality ◽  
Mag Welding ◽  
Shielding Gases ◽  
Shielding Gas ◽  
Advantages And Disadvantages ◽  
Protection Method ◽  
Welding Materials

The hot dip galvanizing process is the most popular long-term corrosion protection method for welded constructions. The article analyzes influence of shielding gas by reducing the zinc layer on the seams in MAG welding. The influence of shielding gases on the geometry of the seam and the slagging of the slag is analyzed. Advantages and disadvantages of the applied gas are presented and the thickness of the zinc layers is compared.

Research on Welding Repair for Reheating Hot Pipe Elbow of 325MW Station Boiler

2012 ◽  
Vol 516-517 ◽  
pp. 414-418 ◽  
Author(s):  
Xiang Feng Zheng ◽  
Qing Wang ◽  
Yan Ting Feng ◽  
Xiao Guang Niu ◽  
Xiao Jun Hao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Base Metal ◽  
Heat Input ◽  
Welding Residual Stress ◽  
Fusion Line ◽  
Metallographic Examination ◽  
Microscope Analysis ◽  
Metal Material ◽  
Pipe Elbow

Through methods, such as microscope analysis, metallographic examination, the crack located nearby the fusion line between reheating hot pipe elbow and blocking valve is reheat crack. The base metal material and excessive welding residual stress are the primary inducement of crack. In replacing pipe elbow, the measures of reducing residual stress, such as hammer blowing ,lower welding heat input, post welding heat treatment and so on, were taken. The welding repair succeeded greatly.

scholarly journals Effect of Shielding Gases on the Wire Arc Additive Manufacturability of 5 Cr – 4 Mo Tool Steel for Die Casting Mold Making

2020 ◽  
Vol 58 (12) ◽  
pp. 852-862
Author(s):  
Jae-Deuk Kim ◽  
Jae Won Kim ◽  
Joo Yong Cheon ◽  
Yang-Do Kim ◽  
Changwook Ji
Keyword(s):  
Tool Steel ◽  
Die Casting ◽  
High Potential ◽  
Shielding Gases ◽  
Delivery Time ◽  
Shielding Gas ◽  
Tool Steels ◽  
Material Loss ◽  
The Wire ◽  
Wire Arc Additive Manufacturing

Generally, molds are fabricated by the machining of massive billets of tool steels, such as AISI4140 or H13, but it has drawbacks, such as a large material loss and long-delivery time. The Wire-Arc Additive Manufacturing (WAAM) process could be an alternative fabrication method. It has the advantages of less material loss, short-delivery time, and the chance to make a reinforced mold using dissimilar materials. 5 Cr – 4 Mo steel wire has high potential to produce molds via the WAAM process. This is a commercial tool steel solid wire initially designed for the repair and modification of tools and molds that has superior hot wear resistance and toughness. However, no study has examined the WAAM of tool steels, even though it has high potential and advantages. Shielding gas has a significant effect on the performance of the WAAM process, which is based on gas metal arc welding (GMAW). Argon (an inert gas) and carbon dioxide (a reactive gas) are generally used for the GMAW of steel alloys, and they are frequently used as mixed gases at various ratios. Shielding gases have a significant influence on the arc stability, weld quality, and formation of weld defects. Therefore, using a proper shielding gas for the material and process is important to sound WAAM performance. This paper discusses the effect of the shielding gas on the additive manufacturability of tool steel, as a first step for the WAAM of die casting molds. The experiments were conducted with two different shielding gases, M21 (Ar + 18% CO2) and C1 (100% CO2). The use of C1 showed neither surface contamination nor internal defects, and resulted in a larger amount of deposition than the M21.

The Influence of the Type and Pressure of Shielding Gas on the Porosity Formation for CO2 Laser Welding of TA15

2013 ◽  
Vol 753-755 ◽  
pp. 372-378 ◽  
Author(s):  
Ai Qin Duan ◽  
Shui Li Gong
Keyword(s):  
Laser Welding ◽  
Molten Pool ◽  
Ti Alloy ◽  
Shielding Gases ◽  
Weld Penetration ◽  
Direct Relation ◽  
Shielding Gas ◽  
Porosity Formation ◽  
Strong Relation ◽  
The Times

Many studies have shown that during laser welding, shielding gases play a key role in many aspects. In this paper, a series of contrast experiments about CO2laser welding of TA15 TI-alloy were completed by using He and Ar as shielding for different pressure, respectively. The experiments results reveal that the porosities in the weld have strong relation with weld penetration, and the shielding gas have great influences on the weld penetration. So the porosities mainly form in the center of welds which are under critical penetration and lack of penetration, and have no direct relation with the type and pressure of shielding gas.From the contrast images of penetrating process, it is known that when He as shielding gas, the sizes of keyholes on the back welds are quite larger than the sizes when Ar. This means more vapor erupting from bottom keyhole and porosities not easy to form. At the same pressure, the opening times of keyholes when He as shielding gas are longer than the times when Ar. Long opening times of keyholes make the shielding gas within keyhole not easy to be involved into the molten pool and form the porosities.

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