精心整理(1)牌号和化学成分见表3-6、表3-7。(2)力学性能见表3—8。(3)用途见表3-9。表3—6优质碳素结构钢的牌号和化学成分统一数序号字代号12345678910111213141516171819U20080U20l00U20150U20082U20102U20152U20202U20252U20302U20352U20402U20452U20502U20552U20602U20652U20702U20752U2080208F10F15F08lO1520253035404550556065707580牌号CO.05~O.11O.07~O.130.12~O.180.05~O.110.07~O.13O.12~0.18化学成分(质量分数)(%)Si≤0.03≤O.07≤O.07O.17~O.370.17~O.370.17~O.37Mn0.25~0.50O.25~O.500.25~O.50O.35~O.650.35~0.65CrM≤0.10O.150.25O.300.250.300.300.250.25O.25O.25O.25O.25CuO.10O.300.15O.30O.35~0.65O.25O.300.35~0.65O.50~O.80O.50~O.80O.50~O.B0O.50~O.800.50~0.800.50~0.80O.25O.30O.17~0.230.17~0.37O.22~0.29O.27~O.34O.32~0.390.37~O.44O.42_O.500.47~0.55O.52~0.600.57~O.650.17~O.37O.17~O.37O.17~O.370.17~O.37O.17~O.370.17~O.37O.17~O.370.17~O.37O.25O.300.250.250.25O.300.25O.300.25O.250.25O.25O.25O.25O.300.250.25O.30O.300.30O.50~0.80O.250.50~O.80O.25O.300.25O.50~O.80O.50~O.800.50~0.80O.50~O.80O.25O.300.250.250.25O.30O.30O.25O.25O.25O.62~0.700.17~0.37O.67~0.750.17~0.37O.72~0.80O.77~0.850.17~O.37O.17~0.37O.300.25精心整理20212223242526272829303lU20852U21152U21202U21252U21302U21352U21402U21452U21502U21602U21652U217028515№20Mn25Mn30Mn35Mn40Mn45Mn50Mn60Mn65Mn70MnO.82~0.90O.12~O.180.17~O.23O.22~O.290.27~O.34O.32~O.39O.37~0.440.42~0.50O.48~0.560.57~0.650.62~0.70O.17~0.37O.17~O.37O.17~O.370.50~O.80O.25O.30O.25O.70~1.00O.25O.300.25O.70~1.00O.250.30O.25O.250.17~0.37O.70~1.00O.25O.30O.17~0.37O.17~O.37O.17~0.370.17~O.37O.17~O.37O.17~O.370.17~O.370.70~1.00O.70~1.00O.70~1.000.70~1.00O.70~1.000.70~1.00O.25O.300.250.250.25O.300.30O.25O.25O.250.250.250.25O.25O.25O.300.250.250.300.300.30O.90~1.20O.250.90~1.200.67~O.750.17~0.37O.25O.30注:1.表中所列牌号为优质钢。如果是高级优质钢,在...