Shielding gas

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

Method and apparatus for the control of shielding gases used in power laser processes

Abstract: In order to remove the plasma cushion and loose metal material created by the action of the laser on a metal workpiece, a shielding gas jet is directed from a nozzle across the workpiece surface through the zone of action of the laser beam. The shielding gas rather than being allowed to go to waste is collected, purified of the metal material contained therein and fed back to the nozzle. This recirculation of the shielding gas is effected in ducting which incorporates in succession between the gas-collecting input end and the nozzle, a diffuser to slow the gas, a cooling chamber, a separator for removing metal particles condensed out of the stream, a pump, a filter and further cooling means.

Active gas plasma arc torch and a method of operating the same

Abstract: An active gas plasma arc torch and a method of operating the same, said torch including a rod-shaped cathode, a first gas passage formed around said cathode to feed a protecting gas or shielding gas, a second gas passage formed around said first gas passage to feed a plasma gas and a constricted port for discharging the plasma gas, characterized in that at least a part of the shielding gas which flows out from the first gas passage is removed from the inside of the torch at the position short of said constricted port of the torch, whereby the working quality and the working speed are substantially improved while the rod-shaped cathode is satisfactorily protected by the shielding gas.

Torch for gas shielderd arc welding using consumable electrode

Abstract: A welding torch comprises a torch body having a wire guide cylinder for guiding a welding wire; an internal cylinder fitted to the torch body in such a manner as to surround the wire guide cylinder; and an external cylinder fitted to the internal cylinder in such a manner as to surround the internal cylinder. The primary interception of outside air is effected with a second shielding gas layer blown off from a second gas passageway on the outer side, and the complete interception of outside air is effected with a first shielding gas layer blown off from a first gas passageway on the inner side. Consequently, it is made possible thereby to sufficiently prevent outside air from reaching a molten pool and also sufficiently suppress the generation of an unfavorable surface oxide, thus enabling welding work to be satisfactorily practiced by using the above welding torch.

A model for heat and mass input control in GMAW

Abstract: This work describes derivation of a control model for electrode melting and heat and mass transfer from the electrode to the work piece in gas metal arc welding (GMAW). Specifically, a model is developed which allows electrode speed and welding speed to be calculated for given values of voltage and torch-to-base metal distance, as a function of the desired heat and mass input to the weldment. Heat input is given on a per unit weld length basis, and mass input is given in terms of transverse cross-sectional area added to the weld bead (termed reinforcement). The relationship to prior work is discussed. The model was demonstrated using a computer-controlled welding machine and a proportional-integral (PI) controller receiving input from a digital filter. The difference between model-calculated welding current and measured current is used as controller feedback. The model is calibrated for use with carbon steel welding wire and base plate with Ar-CO[sub 2] shielding gas. Although the system is intended for application during spray transfer of molten metal from the electrode to the weld pool, satisfactory performance is also achieved during globular and streaming transfer. Data are presented showing steady-state and transient performance, as well as resistance to external disturbances.