Abstract:
Analyzed here in the essay are the micro-structural properties of the as-hot-rolled and as-normalized X52NS acid-resistant linepipes as made of 14MnV and 14MnVTi steels. As a result,it is revealed that in the as-hot-rolled state,the 14MnVTi steel pipe containing Element Ti has finer grain size,which means that Ti plays a role in refining the grain,and that the yield strength slightly higher than that of the non-Ti 14MnV pipe;after the normalization treatment,the non-Ti 14MnV pipe has much finer grain size,and both of its tensile strength and impact energy value are higher than those of the Ti-containing steel pipe;due to the affinity of Ti and V are stronger than that of V,N in the steel first binds with Ti,and thus no more N remained to bind with V,which influences the composite precipitation strengthening effect. Therefore as for the X52NS acid-resistant linepipe,the overall mechanical properties of the 14MnV steel are better than those of the 14MnVTi steel.