... 4.grade:8.8,10.9,12.Bolts and nuts:Mechanical Properties1, Material: 40 Cr.2, Tensile strength: Mpa quartile 1220 ( ... was 10.9, 12.9 grade steel bolts. Steel bolts for the main power system, the machinery industry, the pharmaceutical industry ... kinds of high quality products such as bolts, high strength bolts, screws, nuts, threaded rod, anchor bolt, nail, other off-standard fasteners and following ...