由于热变形形成纤维***，会使金属的力学性能出现异向性，即纵向力学性能指标中的A，Z，Ak比横向相应的指标大得多，两个方向上的强度Rm。Re差别不大。
Due to the formation of fibrous microstructure by thermal deformation, the mechanical properties of metals will be different. That is, A, Z and Ak in longitudinal mechanical properties are much larger than those itransverse direction, and the strength in two directi is Rm. Re is not very different.
随着电动机的发明，十九世纪末出现了以电为动力的机械压力机和空气锤，并获得迅速发展。第二次以来，七十五万千牛的模锻水压机、一千五百千焦的对六万千牛的板料冲压压力机、十六万千牛的热模锻压力机等重型锻压机械，和一些自动冷镦机相继问世，形成了门类齐全的锻造机械体系。自由锻造是靠人工操作来控制锻件的形状和尺寸的，所以锻件精度低，加工余量大，劳动强度大，生产率也不高，因此它主要应用于单件、小批量生产。
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 h***e come out in succession, forming a complete system of forging machinery.
锻造工艺过程一般由以下工序组成，即选取钢坯下料、加热、成形、锻后冷却。锻造的工艺方法有自由锻、模锻和胎膜锻。生产时，按锻件质量的大小，生产批量的多少选择不同的锻造方法。
The forging process is generally of the following processes, namely, the selection of high quality billets, heating, forming and cooling after forging. The forging process includes free forging, die forging and fetal membrane forging. When manufacturing, according to the size of forgings and the number of production batches, different forging methods are chosen.
自由锻造的设备分为锻锤和液压机两大类。生产中使用的锻锤有空气锤和蒸汽-空气锤，有些厂还使用结构简单，***少的弹簧锤、夹板锤、杠杆锤和钢丝锤等。
The equipment of free forging can be divided into two categories: forging hammer and hydraulic press. The forging hammers used in production are air hammer and steam-air hammer. Some factories also use spring hammer, splint hammer, lever hammer and steel wire hammer with simple structure and low investment.