鍛件加工擴孔的基本方法有哪些?擴孔的辦法大致有沖子擴孔、芯棒擴孔和劈縫擴孔三種。

　　What are the basic methods of forging processing reaming Reaming? Measures are punch reaming, mandrel reaming and split seam hole three.

　　1、沖子擴孔：這種辦法是在坯料上用小沖子先沖一孔，再用較大的沖子過一下，可將孔擴展一些，逐漸將孔擴到請求的尺度，多用于孔徑在300mm以內的擴孔。

　　1, punch hole: this approach is to punch a hole with small punch in the blank, and then have a large punch, the hole expansion, gradually expanding to the request of the pore scale, used for reaming diameter within 300mm.

　　2、芯棒(馬杠)擴孔：首要用于環形件鑄造。是將芯棒穿入已沖過孔的坯料，并支撐在馬架上，在鑄造中邊錘擊邊滾動邊送進坯料，使坯料沿圓周在芯棒和上砧間反復遭到鍛訂被延伸，直到內徑到達請求尺度停止。

　　2, mandrel (horse bar) reaming: mainly used for ring casting. Is the blank has crossed the hole through the mandrel, and supported on the trestle, the casting side hammer while rolling edge to the blank, the blank and mandrel along the circumference in the upper anvil forging was repeatedly set was extended, until the diameter scale arrival request stop.

　　3、劈縫擴孔：在坯料上先沖出兩個小子孔后，把兩孔間的金屬剁開，用沖子脹開切斷再擴孔，鍛件加工以到達鍛件請求的尺度。這種辦法用于鑄造大孔徑薄壁鍛件或鑄造外形是不規則的帶孔薄壁鍛件。

　　3, crack expanding: first out of the two small holes in the blank, the metal cut between two holes, cut and reaming punch bulging, forging processing to forging scale request. The method is used for casting large aperture thin-wall forgings or casting shapes, and is an irregular thin-walled forging with holes.