Hadfield steel

Figure 7.8. Material hardness of Hadfield steel subject to shock compression of various peak pressures and pulse durations.

Champion and Rohde [42] investigate the effects of shock-wave amplitude and duration on the Rockwell C hardness [41] and microstructure of Hadfield steel over the pressure range of 0.4-48 GPa (pulse duration of 0.065 s, 0.230 ls, and 2.2 ps). The results are shown in Fig. 7.8. In addition to the very pronounced effeet of pulse duration on hardness shown in Fig. 7.8, postshoek electron microscope observations indicate that it is the final dislocation density and not the specific microstructure that is important in determining the hardness. 

A.R. Champion and R.W. Rohde, Hugoniot Equation of State and the Effect of Short Stress Amplitude and Duration on the Hardness of Hadfield Steel, J. Appl. Phys. 41,2213-2223 (1970). 

Principal applications of Detasheet expls include field demolition, underwater explosions, seismic prospecting and metal cutting and hardening. For example, manganese (Hadfield) steel can be hardened by inducing a shock wave in the metal thru detonation of Detasheet placed direcdy on the metal s surface (Ref 5, p 5)... 

Material Rolled steel Hadfield Steel Kevlar 29/PVB Phenolic Kevlar 129/PVB phenolic Twaron/PVB phenolic Thermoplastic aramid Spectra/Dyneema Hybrids... 

Hadfield steel is an old steel but still in modern use. It takes its name from its 19 -century British inventor Sir Robert Hadfield. The composition is 13% Mn, 1% Cr and 1.25% C. This steel gets harder when it is used as a wear-resistant material in jaw-crushers, teeth for earth-moving equipment, railway points, etc. 

Reprinted from R. Hadfield, Journal of the Iron and Steel Institute, 1912,85.)... 

The elements manganese, nickel, and cobalt have a pronounced tendency to decrease the rate of transformation of y iron to a iron on cooling, and if present in sufficient quantity may enable fee iron to be stable at room temperature. Examples of alloy steels that have an austenitic (fee) matrix at room temperature are Hadfield s steel which contains 12 wt % manganese and 18-8 stainless steel which contains 18 wt % chromium and 8 wt % nickel. Other austenitic materials are the high temperature alloys that are used in aircraft gas turbines. 

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