The relative abundance of the alloying elements in the phases is in wt%. Note that the EDX composition simply shows the relative abundance of the alloying elements within an area in the phase and has no direct relationship with the steel overall composition shown in Table 2. In Fig. 5(b to d), locations 1, 3, 4, 16, 21, 30, etc., are areas of analyses on the αHR , while 2, 5, 17, 25, 28, etc. are areas on the αLR . The light etching is theP , e.g. locations 6, 7, 8, 13, 26 etc. In Table 3, simple observation of the EDX results show that the alloying compositions of αLR andαHR are almost the same. But for theαHA , all other alloy compositions are generally the same with that of αLR andαHR except that the amount of C, Si, Al and O are higher. The Fe content of αHA and P are close, but lower than those of αLR andαHR . This tends to suggest thatαHA is a ferrite phase with the highest concentration of alloying solutes. The P is found to have generally the same composition with the αHA , but with higher oxygen content. An important note here is that the concentration of these solutes may weaken this phase, making it an easy path for FCG . General observed phase morphologies of J2N, G8 and G10 are shown in Fig. 6. Fig. 6 (a & b) are that of J2N obtained in the through thickness direction. The same basic microstructural features as presented in Fig. 5(a) were also observed in Fig. 6 (a & b). Fig. 6(c to i) present microstructural features in the TMCP steels which are basically the same as that found in the J2N steel. For the TMCP , the \(P\) formed mainly between boundaries of the ferrite grains and with width that is relatively small. In the NR steel, \(P\) forms as dense and blocky phase in the αmatrix.