Medium plate mill is used in rolling equipment for rolling steel plate at medium thickness. Such medium plate is widely used in various sectors of national economy; find application in the manufacture of transport (such as automobiles, tractors, ships, railway vehicles and aviation machinery etc.), steel structure parts (such as various storage containers, boilers, bridges and other industrial structures), piping and general machinery products. As the former Ministry of Metallurgical Industry standards required: plate thickness of 4 mm or less is referred to as thin sheet; thickness of 4 mm or more is referred to as thick sheet;. The thickness of steel plate used in the range of 4 to 25 mm is referred to as medium plate. Hot-rolled plate production are currently used for medium plate manufacture. After the upcoming heating billets or ingots, under process of multi-pass rolling and finally roll into a certain thickness of the plate.

The rolling mill to fabricate medium plate is various and wide, upon mill base support structure, can be divided into two-rolled, four- rolled, combined and universal several kinds, upon mill base support setting, can be divided into a single rack , side-by-side rack and longitudinal aligned several types. In general, according to the working surface roller surface length to nominate the specification of medium plate strip mill, such as specified in 2300mm, 2800mm, 5500mm and so on. The current world's largest mill is 5500mm.
 

NHI is the earliest to design and fabricate medium plate, and after decades of development has a variety of specifications series of plate mill, of which four-roller reversible medium plate mill already became the main model, to meet the needs of modern plate mill, NHI constantly explores as large-scale, sophisticated, automated and to fabricate high intensity alloy steel employed control rolling technology. Also NHI expand self-designed and self-manufactured medium plate mill on non-ferrous alloy materials as zinc, lead, titanium and etc, as well as three-rolled Lauth mill for copper plate rolling.