闭口式机架为一整体铸件制成。这类设备的主要优点是相对刚度较大，压下量大、轧延力小，可轧制较薄的板材，也包括有可逆和连轧两种。这种机架形式在型钢车间中小型轧机上应用较多。其优点是强度和刚度较高，辊跳值较小，产品精度较高。其主要缺点是制造比较困难，装卸、换辊不方便。轧制压力较大、对轧件尺寸要求比较严格时常采用闭口式机架。如初轧机、型钢连轧机和型钢成品轧机等。

The closed frame is made of a whole castings. This type of frame is used more in the ***all and medium mill in the steel workshop. Its advantages are that the strength and stiffness are high, the roll jump value is ***all and the precision of the product is high. Its main disadvantage is that it is difficult to manufacture, and it is inconvenient to load and load and change the roll. When the rolling pressure is larger and the requirements for the size of the rolled piece are strict, the closed frame is often used. Such as the early rolling mill, the type steel continuous rolling mill and the steel finished rolling mill, etc.

轧制时毛坯的位置固定，因此不需设置侧向支撑毛坯的导向尺。总之，它适用于轧制复杂外形结构，精度要求高，零件品种变换很多的情况。但其行程大小受到限制，所以，变形程度也受到影响，同时，板式轧机有空行程，故影响到生产率和变形程度都不能很大。

The of the blank is fixed during rolling, so there is no need to set the guide bar of the side supporting blank. In short, it is suitable for rolling complex shape structure with high accuracy and many varieties of parts. But the stroke size is limited, so the degree of deformation is also affected. At the same time, the plate mill has an empty tr***el, so the productivity and deformation can not be very large.

四棍轧机的工作辊直径较小，传递轧制力矩，轧延压力由直径较大的支承辊承受。这类设备的主要优点是相对刚度较大，压下量大、轧延力小，可轧制较薄的板材，也包括有可逆和连轧两种。

The working roll diameter of the four bar mill is ***all, and the rolling torque is transferred. The rolling pressure is borne by the backup roller with larger diameter. The main advantages of this type of equipment are relatively large stiffness, large reduction, low rolling force, thin rolled sheets, and reversible and continuous rolling two.

在对轧机进行分类的时候，一般是按照轧辊的排列和数目进行分类。下面我们就来了解下具体的内容。比如二辊轧机，其的主要特点就是结构简单、用途广泛，也包括可逆式和不可逆式两种。

When classifying rolling mills, they are generally classified according to the number and arrangement of rolls. Next we will find out the specific content. For example, two-high mill, its main features are simple structure, wide range of uses, including reversible and irreversible two kinds.