Usually, excellent Superplasticity of Zn-Al eutectoid alloy could be obtained by pre-deformation (rolling or forging).

锌铝共析合金具有良好的超塑性，但通常需要经过预变形(轧制或锻压)来得到。

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For the convenience of casting, machining, transporting, etc, the beam of large-scale hydraulic forging press has always been designed as combined structure and connected with pre-stress bolts.

大型液压机的横梁由于铸造、加工、运输等原因，大多设计成组合结构，采用预紧螺栓组连接。

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The billet was at first pre formed and close-die forged on different hydraulic presses and then the forging was rolled, punched and bended. Such a production line will be the most efficient.

钢坯先在一台水压机上预成形制坯，再在另一台压机上模锻，经轧制扩径后冲孔压弯。

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