| 摘要 |
<p>The tube is made from thin metal strip which is bent to form a circular outer sleeve with its two longitudinal edges making a butt joint. The sleeve is filled with the material being added to the melt, plus a thin curved foil which separates the material from the joint. The butt joint is pref. welded. The thin foil is pref. bent to form a recess under the joint, esp. to protect the material when the joint is being welded after filling the sleeve with a material. Material is pref. a deoxidiser, a carburiser, a desulphuriser, or an alloying element, and may include a longitudinal wire or spiral forming part of these materials. Used e.g. for adding CaSi powder to molten steel.</p> |
