Page 337 - Manufacturing Engineering and Technology - Kalpakjian, Serope : Schmid, Steven R.
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-                          \\ 0                                Introduction   3


                                                                                   Section 13 1




                                   ~e   1
                                                          Hot strip
                                                                         Pickling and
                                                                                        Cold strip
                                                                           oiling
                                           1
                                                        i,}!‘\`!llu
                                                             \ ';:42':':`; X Irgél
                                          Slab             A Skelp        >

                                                                            Welded pipe
                                                                           l


                                                         »»1i:u@!» ,
                                                                           Steel plates
                                                            Plate
                                                          ,Jw (4   *
                                                        el.;
                                                                _I
                                                                                  "`

                                                        Hot-rolled bars    Cold-drawn bars ‘

               Continuous            I3 'l‘@              Q \ pup;  H      V,
                                         ~-_
                casting or
                                     A   #if**>  VY:-;§U;;Tg Wire
                   ingots                                                         p
                                          Billet                 Rods      '

                                                                            Seamless pipe


                                                        Tube rounds
                                ._ ,F                  Structural shapes
                                                        l'g§s&.






                                        B'°°m           -»»l§-ll»t!»ll~


                                                                Rails

               FIGURE I3.l  Schematic outline of various flat-rolling and shape-rolling processes.
               Source: After American Iron and Steel Institute.

                   Rolling first is carried out at elevated temperatures (hot rolling). During this
               phase, the coarse-grained, brittle, and porous structure of the ingot (or the continu-
               ously cast metal) is broken down into a wrought structure having a finer grain size and
               enhanced properties, such as increased strength and hardness. Subsequently, rolling
               typically is carried out at room temperature (cold rolling), whereby the rolled product
               has higher strength and hardness and a better surface finish. However, it requires
              more energy (because of the higher strength of the material at room temperature) and
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