冶金分析
冶金分析
야금분석
METALLURGICAL ANALYSIS
2015年
6期
19-25
,共7页
9 Ni钢%冲击性能%微观组织%镍偏析%残余奥氏体%枝晶
9 Ni鋼%遲擊性能%微觀組織%鎳偏析%殘餘奧氏體%枝晶
9 Ni강%충격성능%미관조직%얼편석%잔여오씨체%지정
9 Ni steel%impact property%microstructure%nickel segregation%retained austenite%dendritic crystal
对冲击性能不同的9 Ni钢试样从微观方面进行了比对分析，用扫描电子显微镜、金相显微镜、电子探针和扫描电镜电子背散射衍射( EBSD)进行组织、非金属夹杂物、奥氏体晶粒、低倍枝晶和残余奥氏体量的观察研究。研究结果表明：冲击功值低的试样断口呈脆性解理断裂，低倍枝晶形貌图显示柱状晶发达，奥氏体晶粒粗大且不均匀；而冲击功值高的试样断口呈韧性断裂，各晶区可明显区分，奥氏体晶粒细且均匀。两组试样的夹杂物评级没有明显差异，说明两组试样的冲击性能差异是由于不恰当的连铸工艺使得柱状晶过于发达，铸态枝晶间形成富镍的偏析带，镍的偏析带在随后的热加工中不能被完全消除而遗传下来，造成了钢板镍元素的微观偏析，引起了组织不均匀，并降低了9 Ni钢的冲击性能。
對遲擊性能不同的9 Ni鋼試樣從微觀方麵進行瞭比對分析，用掃描電子顯微鏡、金相顯微鏡、電子探針和掃描電鏡電子揹散射衍射( EBSD)進行組織、非金屬夾雜物、奧氏體晶粒、低倍枝晶和殘餘奧氏體量的觀察研究。研究結果錶明：遲擊功值低的試樣斷口呈脆性解理斷裂，低倍枝晶形貌圖顯示柱狀晶髮達，奧氏體晶粒粗大且不均勻；而遲擊功值高的試樣斷口呈韌性斷裂，各晶區可明顯區分，奧氏體晶粒細且均勻。兩組試樣的夾雜物評級沒有明顯差異，說明兩組試樣的遲擊性能差異是由于不恰噹的連鑄工藝使得柱狀晶過于髮達，鑄態枝晶間形成富鎳的偏析帶，鎳的偏析帶在隨後的熱加工中不能被完全消除而遺傳下來，造成瞭鋼闆鎳元素的微觀偏析，引起瞭組織不均勻，併降低瞭9 Ni鋼的遲擊性能。
대충격성능불동적9 Ni강시양종미관방면진행료비대분석，용소묘전자현미경、금상현미경、전자탐침화소묘전경전자배산사연사( EBSD)진행조직、비금속협잡물、오씨체정립、저배지정화잔여오씨체량적관찰연구。연구결과표명：충격공치저적시양단구정취성해리단렬，저배지정형모도현시주상정발체，오씨체정립조대차불균균；이충격공치고적시양단구정인성단렬，각정구가명현구분，오씨체정립세차균균。량조시양적협잡물평급몰유명현차이，설명량조시양적충격성능차이시유우불흡당적련주공예사득주상정과우발체，주태지정간형성부얼적편석대，얼적편석대재수후적열가공중불능피완전소제이유전하래，조성료강판얼원소적미관편석，인기료조직불균균，병강저료9 Ni강적충격성능。
The microstructure of 9Ni steel samples with different impact properties was compared and analyzed. The structure, non-metallic inclusion, austenite grain, low-magnification dendritic crystals and the amount of retained austenite were observed and investigated by scanning electron microscope, metallographic microscope, electronic probe and scanning electron microscope-electron backscatter diffraction ( EBSD ) . The research results indicated that:the fracture of sample with low impact property showed brittle cleavage fracture, the low-magnification den-dritic crystal morphology figure indicated columnar crystal was developed, and the austenite grains were bulky and non-uniform. However, the fracture of sample with high impact property showed ductile fracture, the crystalline re-gions could be well differentiated, and the austenite grains were fine and uniform. The grade of inclusions in two groups of samples had no significant difference, indicating that the difference of impact properties between samples was due to the over-developed columnar crystal caused by improper continuous casting process. The nickel-rich seg-regated band was formed between as-cast dendritic crystals. The segregation band of nickel could not be fully re-moved in the following thermal processing and be passed down, resulting in the micro-segregation of nickel element in steel plate. As a result, the impact property of 9Ni steel was reduced due to the non-uniform structure.
