Mild steel stress-strain curve

Finally, mild steel can sometimes show an instability like that of polythene. If the steel is annealed, the stress/strain curve looks like that in Fig. 11.10. A stable neck, called a Luders Band, forms and propagates (as it did in polythene) without causing fracture because the strong work-hardening of the later part of the stress/strain curve prevents this. Luders Bands are a problem when sheet steel is pressed because they give lower precision and disfigure the pressing. 

Fig. 4-2(1) Example of a tensile stress-strain curve for mild steel pipe material.

Figure 2.5 Schematic stress-strain curve for a metallic specimen such as wrought iron or mild steel...

Figure 8.10 Mild steel s tensile stress-strain curve...

Figure 5.13 Typical stress-strain curves for FRP and mild steel...

Concerning the effect of the hydrostatic pressure on the mechanical properties of metals, it was found that the hydrostatic pressure had no effect on the lower yield stress for mild steel nor on the stress-strain curve for silicon-aluminium alloy. However, a small reduction in the upper yield stress was observed on mild steel [16]. For more strain hardened specimens the decrease in yield stress was much higher. In unanimous option of all researchers the deformability increases under effect of superimposed hydrostatic pressure [16]. 

There is, however, a significant difference between polymers and many metals with regard to yield behaviour. For a polymer, as shown in Figure 11.4, stress increases continously once strain-hardening takes effect, in contrast with metals (illustrated by mild steel in Figure 11.14), where often two maxima are observed on a t3qjical load extension curve. The first maximum (point A in Figure 11.14), called the upper yield point, represents a fall in true stress an intrinsic load drop... 

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