The present invention provides on-line cold bent steel secondary punch mold and punching method, and belongs to the field of plastic forming technology for metal.

本发明提供了一种在线冷弯型钢二次冲切模及其冲切方法，属于金属塑性成型技术领域。

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Tesla's invention is, in essence, a rotating transformer. Its primary windings reside in a stationary steel casing (the stator) and and secondary conductors are attached to an inner shaft (the rotor).

尼古拉·特斯拉发明的感应电动机本质上就是一台旋转变压器——首先在电动机的固定钢制外壳（定子）上安装上绕组，然后将导体安装入内轴（转子）。

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Around all this sits the steel and concrete of the secondary containment structure.

所有上述结构又被包裹在一个钢筋混凝土结构中——二级安全壳。

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Bush-era trade quotas on steel demonstrate a secondary effect of trade restrictions.

FORBES: Two Cheers For A Big U.S. Trade Deficit