碾環(huán)是指通過專用設(shè)備碾環(huán)機生產(chǎn)不同直徑的環(huán)形零件，主要用來生產(chǎn)汽車輪轂、火車車輪等輪形零件。特種鍛造包括輥鍛、楔橫軋、徑向鍛造、液態(tài)模鍛等鍛造方式，這些方式都比較適用于生產(chǎn)特殊形狀的零件。

Roller ring refers to the production of circular parts with different diameters through the roller ring machine of special equipment, which is mainly used to produce wheel hub, train wheel and other wheel shaped parts. Special forgings include roll forging, cross wedge rolling, radial forging, liquid forging and so on. These methods are suitable for producing parts with special shape.

隨著電動機的發(fā)明，十九世紀(jì)末出現(xiàn)了以電為動力的機械壓力機和空氣錘，并獲得迅速發(fā)展。自由鍛設(shè)備有空氣錘、蒸汽-空氣錘和水壓機等，分別適合小、中和大型鍛件的生產(chǎn)。第二次以來，七十五萬千牛的模鍛水壓機、一千五百千焦的對六萬千牛的板料沖壓壓力機、十六萬千牛的熱模鍛壓力機等重型鍛壓機械，和一些自動冷鐓機相繼問世，形成了門類齊全的鍛造機械體系。

With the invention of motor, the mechanical press and air hammer powered by electricity appeared at the end of nineteenth Century, and developed rapidly. Since the Second World War, the forging water press, one thousand and five hundred thousand char, the punching press of Liu Wanqian cattle, the hot forging press of sixteen thousand thousand cattle, and some automatic cold heading machines have come out in succession, forming a complete system of forging machinery.

自由鍛造所用工具和設(shè)備簡單，通用性好，成本低。 同鑄造毛坯相比，自由鍛消除了縮孔、 縮松、氣孔等缺陷，使毛坯具有更高的力學(xué)性能。鍛件形狀簡單，操作靈活。

Free forging tools and equipment are simple, versatility and low cost. Compared with the casting blank, the free forging eliminates the defects such as shrinkage porosity, porosity, porosity and so on, so that the blank has higher mechanical properties. The shape of the forgings is simple and the operation is flexible.

在芯棒上拔長。鍛造時，先芯棒插入沖好孔的坯料中，然后當(dāng)作實心坯料進行拔長。拔長時，一般不是一次拔成，先將坯料拔成六角形，鍛到所需長度后，再倒角滾圓，取出芯棒。為便于取出芯棒，芯棒 的工作部分應(yīng)有1：100 左右的斜度。

Pull on the mandrel. When forging, insert the mandrel into the billet of the hole and then pull it out as a solid billet. When drawing, it is not usually drawn at one time. First, the blank is drawn into a hexagonal shape, forged to the required length, then chamfered and rounded, and the mandrel is removed. To facilitate the removal of the mandrel, the working part of the mandrel should have a slope of about 1:100.