[av_textblock size='' av-medium-font-size='' av-small-font-size='' av-mini-font-size='' font_color='' color='' id='' custom_class='' av_uid='av-kjkhozgv' admin_preview_bg=''] There are steel grades that pretty much won’t harden, at least in the most familiar sense. There are steel grades that are hardenable by thermal treatment. And there are…