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采用光学显微镜、电子显微镜和Ｘ射线衍射仪研究了激光表面淬火处理硼铸铁硬化层的显微组织及激光处理前后硼在铸铁中的存在形式。在滑动磨损试验机上测量了激光硬化层的耐磨性。研究结果表明，硼铸铁铸态组织为珠光体＋片状石墨＋微量游离铁素体＋角状化合物（包括Ｆｅ３Ｐ、Ｆｅ３（ＰＢ）及Ｆｅ２Ｂ）。激光淬火处理后组织超细化，熔凝层为树枝状初晶（Ｍ＋Ａ’）和树枝间层片状共晶（变态莱氏体即Ｍ＋Ａ’＋Ｆｅ３Ｃ或Ｆｅ３（ＣＢ））。固态相变层为隐针马氏体、残留奥氏体及未溶解的石墨与硼化物。硼铸铁激光淬火处理后硬度及耐磨性显著高于未经激光处理的硼铸铁和灰铸铁。
The microstructure of boron carbide hardened layer by laser surface quenching and the existence of boron in cast iron before and after laser treatment were studied by optical microscope, electron microscope and X-ray diffractometer. The abrasion resistance of the laser hardened layer was measured on a sliding wear tester. The results show that the castings of boron cast iron are pearlite + flake graphite + trace free ferrite + horn compounds (including Fe3P, Fe3 (PB) and Fe2B). After laser quenching, the microstructure was refined. The melted layer was dendritic primary crystal (M + A ’) and dendritic lamellar eutectic (metamorphosed ledeburite, M + A’ + Fe3C or Fe3 (CB)). Solid state phase change layer for hidden needle martensite, retained austenite and undissolved graphite and boride. Boron cast iron laser quenching hardness and wear resistance was significantly higher than the laser without boron cast iron and gray cast iron.