Pre-grinding is consisted of cycle pre-grinding, hybrid grinding, and combination grinding and semi-finished grinding.

预粉磨分为循环预粉磨、混合粉磨、联合粉磨和半终粉磨。

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As for flat roll of F4 ~ F6 stands, their pre-grinding crowns were optimized and the flatness of strips was greatly improved.

对F4 ~ F6机架平辊的预磨凸度进行优选，明显改善了带钢的平直度。

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Gives a new method which designs tooth forms of pre-grinding hob according to thepartical demands on hob of gear, and designs a kind of pre-grinding hob used in high-speed traction gears.

根据高速牵引齿轮对齿轮滚刀的特殊要求，提出了设计磨前滚刀齿形的新方法，并用此法设计了高速机车牵引齿轮的磨前滚刀。

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