The casting process above the metal recrystallization temperature is called hot forging. Hot forging is also called hot die forging. During casting, the deformed metal moves violently, and the forging and die touch for a long time. Therefore, the mold data are required to have high thermal stability, high temperature strength and hardness, impact toughness, heat fatigue resistance and wear resistance, and easy to process. The hot forging die with light working load can be made of low alloy steel.

除大、中型的自在锻件选用钢锭作为毛坯外，一般锻件都选用各种金属棒料为毛坯。棒料在铸造前，一般要在专门的下料设备上按要求的尺度切成断，常用下料方法如下：

Except that steel ingot is selected as blank for large and medium-sized free forgings, various metal bars are selected as blank for general forgings. Before casting, the bar stock shall be cut according to the required scale on the special blanking equipment. The common blanking methods are as follows:

锯切

Sawing

锯切下料常在圆盘锯和弓形锯及高速带锯上进行。

Sawing and blanking are often carried out on circular saw, bow saw and high-speed band saw.

圆盘锯是由电动机带动带齿的锯盘慢速旋转并移动，将棒料堵截。锯盘的直径可达2m，能够锯切的棒料直径在750mm以下。

The circular saw is driven by the motor to rotate and move the saw disc with teeth at a slow speed to block the bar. The maximum diameter of the saw disc can reach 2m, and the diameter of the bar that can be sawed is less than 750mm.

弓形锯是由电动机带动带齿的锯条作往复移动，把棒料堵截。能够锯切的棒料直径为100mm以下。关于直径特别小的棒料，也能够成捆地锯断。

The bow saw is driven by the motor to move the saw blade with teeth back and forth to block the bar. The diameter of the bar that can be sawed is less than 100mm. Bars with particularly small diameter can also be sawn in bundles.

锯切的特点是切断断面平坦，尺度精确；但出产率较低，有锯口丢失，而且锯条和锯盘的损耗也比较大。高速带锯是一种较的下料设备，出产效率高，且毛坯形状规则。

Sawing is characterized by flat cutting section and accurate scale; However, the production rate is low, the saw mouth is lost, and the loss of saw blade and saw disc is also relatively large. High speed band saw is an advanced blanking equipment with high production efficiency and regular blank shape.