| 摘要 |
On leaving the molten metal bath, the substrate is subjected to an alternating current (A. C.) electromagnetic field (10), which is applied at or below the point where the substrate leaves the bath. The A. C. field is provided round a tube through which the substrate travels upwards, the tube contg. a protective neutral or reducing atmos. gravel, vermiculite, or carbon granules, with its lower end immersed in the bath, the object being to prevent ambient air reaching the coating. Several magnets may be used to apply the field to a row of substrates leaving the molten bath.
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