摘要 |
An outer pipe 10 and an inner pipe 12 are formed by drawing. Inner pipe 12 is inserted into outer pipe 10 and a metal core 14 is inserted into inner pipe 12. From this state, drawing is performed so that outer pipe 10 presses tightly against inner pipe 12. Metal core 14 is pulled out, resulting in a two-layer clad pipe 15. Alternatively, a two-layer clad pipe can also be made by drawing outer pipe 10 and inner pipe 12 without inserting metal core 14.
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