Controlled rolling

Use fully killed or fine grain steel, controlled rolling temperatures high Mn/C ratios eliminate sharp corners in design, remove defects from steel heat treat steel. For cryogenic operations use high nickel alloy steels or austenitic stainless steels, depending on temperature. 

Perhaps the most important innovation of all is in the thermomechanical control processes, involving closely controlled simultaneous application of heat and deformation, to improve the mechanical properties, especially of ultra-microalloyed compositions. Processes such as controlled rolling are now standard procedures in steel mills. 

As a caution, the rolling of tubes into their tubesheets is a very special job that requires experience and feel, even though today there are electronically controlled rolling and expanding tools. The tubes must be just right, not over nor under expanded, to give a good joint and seal. 

In this Fig. 8-41 view (a) the feeder-roll speed to puller-roll speed ratio can be set, such as 1 4, and simultaneously the ratio of width can be set as 1 4. The machined direction ratio is usually accomplished prior to the plastic s entering the temperature controlled oven that contains the tenter frame, by having it move around heat-controlled rolls where the rotational speed of the rolls increases from one roll to the next. View (b) is a schematic of the drawdown phenomenon with swell to produce orientation in the machined (longitudinal) direction. 

Basically the calendering process is used in the production of plastic films and sheets. It converts plastic into a melt and then passes the pastelike mass through roll nips of a series of heated and rotating speed-controlled rolls into webs of specific thickness and width. The web may be polished or embossed, either rigid or flexible (9). One of its sheets major worldwide markets is in credit cards. At the low cost side these lines can start a million. A line, probably the largest in the world... 

Figure 18.3 is an extrusion line schematic drawing of tension control equipment for the unwinding substrate. The arrows indicate the motions of the driven tension control rolls and idlers as well as the substrate, and the direction of outward pressure-on the rolls. Figure 18.4 is what is called a flying splice on a double-station-unrolling stand where ... 

Controlled rolling is most common and consists of the following three stages ... 

Where extension of use is conducted as part of a controlled roll out it should be subject to the usual change management procedures which will have been established in the in SMS. Essentially a set of safety activities will need to take place on the product to determine whether the new operating environment introduces any new hazards and the safety case updated accordingly. The analysis will need to be able to justify operating the system outside of the intended purpose and set out the evidence to support the claim that the risk remains acceptable. 

Figure 27. Fabrication of the FLCP display device, (a) An FLCP-coated substrate is laminated with another ITO polymeric substrate, (b) The laminated sandwich is bent on a temperature controlled roll.

Most rollforming applications in the past have used neither flatteners nor leveling equipment in the coil feed system. The concept was that the rollforming process produced parts that were sufficiently stiff and rigid, and thus, incoming shape was a nonissue. Of course, we saw curvature control rolls being put at the exit of some rollforming mills. 

Accelerated cooling of controlled-rolled steels to enhance the formation of fine ferrite grains. 

These effects have been encountered primarily in steel plate used for vessel construction or for fabrication of welded pipe. The major industry problem has been with welded pipe made from controlled rolled plate. Cases of pipe rupture have been attributed to HIC. Seamless pipe is less subject to these effects, but is not considered to be immune. HIC may be prevented by the manufacturer s control of the inclusion number, size, and shape, particularly sulfide inclusions [72]. 

JAERI studied graphite-C02 reaction and Jet grind method as a head-end reprocessing technique to reduce CO gas release and maintenance for controlling roll-gap clearance in the roll grinder. The feasibility of this method was approved through laboratory scale experiments. 

Deflection control rolls (Section 5.2.3) overcome the disadvantages of deflection of the conventional rolls resulting from internal and external forces. 

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