| 摘要 |
The body of the utensil is of aluminium or aluminium alloy. A bottom layer of ferrous material is applied to it before shaping, the bottom part being so shaped as to accommodate different coefficients of expansion. Alternatively, one or more expansion joints can be included, typically formed by spiral or circular indentations. High-grade steel can be used for the coating, and can be machined before the shaping operation.
|
