| 摘要 |
A gas-metal-arc welding process, utilizing a four-gas mixture and relatively high voltage, produces a high rate of weld metal deposition. The process involves continuously advancing the end of a meltable, thin wire electrode towards a weld metal deposit surface, while maintaining a predetermined length arc gap therebetween. A flow of shielding gas, which is formed of major proportions of argon and helium and minor proportions of carbon dioxide and oxygen, coaxially surrounds and flows along the electrode end portion and arc gap towards the deposit surface. A relatively high electrical voltage and current density are applied to the electrode. A roughly conically-shaped, hot plasma field is formed within the arc gap between the electrode end and the metal deposit surface. The length of the arc gap and the voltage are adjusted to provide a plasma field base diameter which corresponds to and substantially overlaps the width of the weld bead and the narrow band of the metal deposit surface upon which the weld bead is deposited. Drops melted from the electrode are deposited by globular, free-flight transfer across the arc gap upon the deposit surface substantially within the field base diameter. To form the elongated, narrow weld bead, the electrode, with its concentric arc gap band plasma field, is moved sideways in parallel alignment with the axis of the weld bead. Thus, the process may be used for high deposition rate welding within relatively deep, narrow gaps, as well as upon more exposed metal deposit surfaces.
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