Cross rolling

Cross rolling, a technique in which a material is rolled in two directions at right angles to one another in successive rolling passes, may be used for some requirements. Cross rolling tends to intensify BCC textures, whereas the opposite occurs in FCC metals (Honeycombe, 1984). 

In case paving starts from a transverse cold joint, with or without the formation of longitudinal joint, a number of different techniques are used in all cases, the transverse joint is cross rolled first. 

Basal (0002 tilted out of the rolling plane by about 30°) cross rolling in lower (a+(3)-field... 

Roll at 925-950 °C (1700-1750 °F) to final plate size (with cross roll to balance properties)... 

Transverse or cross rolling wedge shaped forms in a pair of rolls create the final shape on short-cropped bars in one revolution. For parts with axial symmetry such as spanners. 

The shape of manganese sulfide inclusions can be partially altered by cross rolling. This method is being used on plate mills for producing high quality steel. Even when this technique is used, the sulfide shape control is incomplete because the inclusions still retain a biaxial ellipsoidal shape. Furthermore, cross rolling on modern continuous hot strip mills is currently impractical. 

Fabrication practice for the core-tank plate was based upon procedures developed by Westinghouse Atomic Power Division [125], but modified by increased cross-rolling to reduce the preferred orientation. The fabrication procedure for the core tank is discussed in detail in Refs. 126 and 127. 

Figure 1 is a cross section of a typical generator tube showing the tube sheet, the location of both the soft and hard roll marks and the typical location of wastage. 

Separations similar to those obtained with dry induced-roll devices can be obtained with cross-belt separators (Fig. 19-42). These units are built with up to eight poles, each of which can operate at different magnetic-field intensities to allow simultaneous production of different concentrates. However, capacity is low, and installed costs per ton capacity are high compared with induced-roll units. 

When metals are rolled or forged, or drawn to wire, or when polymers are injection-moulded or pressed or drawn, energy is absorbed. The work done on a material to change its shape permanently is called the plastic work- its value, per unit volume, is the area of the cross-hatched region shown in Fig. 8.9 it may easily be found (if the stress-strain curve is known) for any amount of permanent plastic deformation, e. Plastic work is important in metal- and polymer-forming operations because it determines the forces that the rolls, or press, or moulding machine must exert on the material. 

Many of these problems can be solved by using continuous casting (Fig. 14.3). Contraction cavities do not form because the mould is continuously topped up with liquid metal. Segregation is reduced because the columnar grains grow over smaller distances. And, because the product has a small cross-section, little work is needed to roll it to a finished section. 

A drop of water that is placed on a hillside will roll down the slope, following the surface curvature, until it ends up in the valley at the bottom of the hill. This is a natural minimization process by which the drop minimizes its potential energy until it reaches a local minimum. Minimization algorithms are the analogous computational procedures that find minima for a given function. Because these procedures are downhill methods that are unable to cross energy barriers, they end up in local minima close to the point from which the minimization process started (Fig. 3a). It is very rare that a direct minimization method... 

To illustrate how this rather complicated structure is built up, we will start by wrapping a piece of string around a barrel as shown in Figure S.16. The string goes up and down the barrel four times, crosses over once at the bottom and twice at the top of the barrel. This configuration is the basic pattern for the jelly roll motif. 

---