Shielding gas

About: Shielding gas is a research topic. Over the lifetime, 6697 publications have been published within this topic receiving 58668 citations.

Universal shielding gas for GMAW and FCAW welding and process

Abstract: A universal shielding gas mixture contains, by volume, about 96.0% argon, 3.0% carbon dioxide, and 1.0% oxygen. This single shielding gas composition can be used for welding ferrous metals, including both carbon steel and stainless steel using a variety of gas metal arc welding (GMAW) processes including short circuit arc, pulse arc, spray arc, metal transfer modes and flux core metal arc welding (FCAW) when welding carbon steel, stainless steel, hardfacing and metal core wires. This universal shielding gas composition will not substantially alter the carbon content of the weld metal chemistry. In a second embodiment, suitable for use with carbon steel materials but not stainless steel, the shielding gas mixture contains, by volume, about 95.0% argon, 3.0% carbon dioxide, and 2.0% oxygen. Another aspect of the invention is a single tank containing the premixed universal shielding gas, and improved gas metal arc welding processes that utilize the disclosed shielding gas mixture.

Narrow groove welding torch

Abstract: A narrow groove welding torch having an internally insulated metallic housing and a rectangular cross section with cooling ducts and shielding gas ducts disposed within the housing.

Effect of underwater local cavity welding method conditions on diffusible hydrogen content in deposited metal

Abstract: One of the methods with great potential for applications in underwater repairs is local cavity welding. In local cavity method, cooling conditions and diffusible hydrogen amount in weld metal are nearly the same as those existed during welding in the air. This paper presents the results of literature survey and preliminary tests of the effect of local cavity welding conditions on diffusible hydrogen amount in a deposited metal. A Plackett–Burman design was applied to screen seven parameters: thickness of elastic cover, stick-out of electrode wire, welding current, voltage, travel speed of welding, salinity of water, and flow rate of shielding gas.

Mapping the droplet transfer modes for an ER100S-1 GMAW electrode

Abstract: Welds were made with a 1.2- mm-diameter AWS ER100S-1 electrode using Ar-2% 02 shielding gas to map the effects of contact-tube- to-work distance (13,19 and 25 mm), current, voltage, and wire feed rate on metal transfer. The droplet transfer modes were identified for each map by both the sound of the arc and images from a laser back-lit high­ speed video system. The modes were cor­ related to digital records of the voltage and current fluctuations. The maps con­ tain detailed information on the spray transfer mode, including the boundaries of drop spray, streaming spray and rotat­ ing spray modes. The metal transfer mode boundaries shifted with an increase in contact-tube-to-work distance. Increas­ ing the contact-tube-to-work distance from 13 to 19 mm resulted in a 1 5 mm/s increase in the wire feed rate for the glob- ular-to-drop-spray transition. isting robotic actuators can duplicate the precision of human arm movements in manipulating the electrode along the joint, but substantial improvements are needed in sensor and control system technology. Monitoring of the electrical signals (through-the-arc sensing) is one sensing strategy for an intelligent welding control system. Electrical perturbations related to metal droplet transfer in gas metal arc welding (GMAW) can be used to sense changes in the welding conditions. The control loop would contain rules based on the expertise of a human welder and allow the controller to make the proper responses to the conditions detected by the sensors. A through-the-ar c sensing strategy does not intrude into the arc re­ gion and eliminates sensor-workpiece in­ terference and sensor blinding problems. Although the electrical signals were correlated to arc characteristics as early as 1955 (Ref. 1), recent advances in dig­ ital signal capture and processing tech-

Fluxes and slags in welding

Abstract: The complex welding technology of today demands an understanding of the formulation, manufacture, performance and use of welding fluxes. The volume of fluxes used in covered-electrode, submerged-arc, flux-cored wire, electroslag, brazing and oxyacetylene techniques, has grown to a total of probably over 400 million pounds per year in the United States. The fact that in the U.S. today the covering on coated electrodes averages approximately 25% of the 600 to 700-million pound annual production is an indication of the importance of welding fluxes. The technology leading to proper flux formulation has been little understood. It is hoped that a presentation of some of the principles of welding flux technology will provide an appreciation of improved quality of weld metal obtained through slag/metal reactions. The choice of compounds and the exact formulation in the preparation of a flux will depend upon many factors, including both technical and production economies.