1、Text,Steel rolling is a continuous or stepwise forming with the aid of more than two rotating rolls. The rolls act on the metal primarily through pressure. Therefore rolling is classified among the pressure-forming methods. Steels may be rolled hot or cold. Hot rolling is carried out at an elevated

2、rolling-stock temperature, and cold rolling is performed without heating.,Hot-rolling mills are generally divided into the following zones: furnace area (for heat supply prior to deformation), rolling area, and finishing area. Rolling stocks will be homogeneously preheated to defined temperature by

3、socking pits in the furnace area. The rolling area completes the rolling process. Rolling trains are normally adapted to the products to be rolled. Hence, there are very many different types of train, such as roughing trains, intermediate and finishing trains.,Text,The most important tasks of the fi

4、nishing shop are: cutting, straightening, surface protection stacking and retrieving, inspection, checking, sorting, marking, collecting, bundling, packing. The sequence and extent of these jobs will depend on the nature of the product.,Text,Cold- rolling mills generally include the following areas:

5、 pickling area, rolling train, heat treatment, and finishing area. Steel is cold rolled mainly for producing flat products such as deep-drawing sheet, tin sheet and stainless sheet. Sectional steel products and tubes are also cold rolled. The most wide-spread process is the cold rolling of strip .,T

6、ext,strip is cold rolled on two-high, four-high or multiple-roll mills. In order to eliminate work hardening after cold rolling, heat-treatment by annealing is frequently applied. A combination of cold forming and heat treatment permits specified technological properties to be obtained.,Text,The adv

7、antage of hot rolling is that it can be reduced in thickness much more easily. But the surface finish and accuracy are not so good as those obtainable by cold rolling. The most general use of hot rolling, therefore, is for “breaking down” large ingots; cold rolling is used to make smooth and accurat

8、e thin sheets of metal. As cold steel is harder than hot steel, cold steel mills need harder rolls and, the power required for cold rolling is greater than that for hot rolling.,Text,Two main groups of rolled steel products are semi-finished products and finished products. Semis are the blooming and

9、 slabbing as well as the hot wide strip. Normally, they are deformed in the steel plants into finished products. Finished products are those whose hot forming has been completed in the rolling mills. Finished rolled steel products are classified according to the shape of their cross-sections as: sec

10、tion product , flat product, tube，and wire rod.,Text,Section products are subdivided into groups each with differing individual profiles. They include: (1) Sectional steel Sectional steel include circular, square, rectangular, octagonal or semi-circular sections, and I, H, U, profiled sections and w

11、ide-flanged beams etc. (2) Reinforcing steel With a diameter measuring 6 to 8 mm, reinforcing steel is also a bar with a circular cross-section. Its surface is usually ribbed. (3) Rail accessories This category covers all the parts needed for building railway tracks.,Text,Flats are rectangular in cr

12、oss-section. The width is much larger than the thickness. The surface is mostly smooth but may also be patterned. Flat products are classified by thickness into: heavy flat steel (60mm), medium steel plat (460mm) and steel sheet (4mm).,Text,Tubes are hollow sections. Although normally circular in cr

13、oss-section, other forms are also produced. Wire rods surface is mostly smooth. Its cross-section may be circular, oval, square, rectangular, etc. Thicknesses rang from 5 to 40 mm. Most wire rod undergoes further treatment by cold drawing or cold rolling.,Text,Translation,軋鋼是在兩個以上旋轉(zhuǎn)軋輥的作用下使金屬連續(xù)成形的工藝。

14、軋輥主要通過壓力作用于金屬, 所以軋鋼歸于壓力成形方法中。 軋鋼有熱軋和冷軋。熱軋在軋件高溫時進行，而冷軋不需要加熱。 熱軋廠一般由以下幾部分組成：加熱爐區(qū)(在變形前提供熱)、軋制區(qū)和精整區(qū)。加熱爐區(qū)負責(zé)把軋件均熱到一定的溫度，軋制區(qū)完成軋制工作。軋制道次要與軋制的產(chǎn)品相適應(yīng), 因此有各種不同的分類。比如，粗軋道次，中軋道次和精道次。成品車間的主要任務(wù)是：切割，拉直，表面保護，堆放和貯存，觀察、檢查分類作標記，收集，捆扎和打包。這些工作的程序和程度將以產(chǎn)品的特性而定。,冷軋廠一般包括以下幾道工序：酸洗、軋制（道次）、熱處理和精整。冷軋主要用于生產(chǎn)板材如深沖薄板，鍍錫薄板和不銹鋼板。型鋼和管材也

15、是可以冷軋的。使用最廣泛的冷軋工藝是帶鋼的冷軋,帶鋼可以在兩輥、四輥和多輥軋機上冷軋。為了消除冷軋后的加工硬化，經(jīng)常用退火來進行熱處理。冷軋和熱處理的結(jié)合可以使鋼材獲得更好的技術(shù)性能。圖16-1軋制工序 熱軋的優(yōu)點是（比冷軋）更容易壓縮軋件的厚度。但是，熱軋件的表面光潔度和精度都不如冷軋的好。因此，熱軋的最大用途是對大鋼錠進行“開坯 ”；冷軋則用來生產(chǎn)平整而精度高的薄金屬板。由于冷軋鋼比熱軋鋼硬，冷軋機需要較硬的軋輥，冷軋需要的動力比熱軋大。,Translation,軋鋼的產(chǎn)品主要有半成品和成品兩種。半成品是板坯，大方坯和熱寬帶鋼，通常它們在鋼廠加工成成品。成品是軋鋼廠已經(jīng)完成熱成形的產(chǎn)品。軋制的成品鋼材按照它們的斷面形狀可分為：型材、板材, 管材、線材(四大類)。 型材可以被細分為各種類型，每一種有不同的形狀。它們是： 型鋼 型鋼包括斷面是圓的、方的、矩形的、八角形的或半圓的等普通型鋼以及I、H、U型斷面的異型斷面鋼材和寬緣鋼梁板等。 鋼筋 鋼筋直徑68 mm，也具有