Ko te mea e 4140, he mea ehara noa ana, he mea e matau ana i tona kaha, i ae me te mahi mahara i roto i nga whakatakotoranga e mahara, i mua i roto i te whakapaingia Ko te whakaaroa "4140" e korerotia ana ki te mea e mahara i roto i te cromium, o te molibdenum, o te karabura e hoatu ana i te mea e tikanga E mahi piso