【摘要】：在Gleeble-3500熱模擬試驗機上,利用應力松弛試驗研究了鈦微合金化IF鋼奧氏體區(qū)第二相粒子析出行為。試驗結(jié)果表明:因第二相粒子析出釘軋位錯與晶界,應力松弛曲線呈現(xiàn)出3個階段的特征。試驗鋼的析出-時間-溫度曲線呈現(xiàn)出典型的"C"曲線形狀,最快析出鼻子點溫度約為900℃,在此溫度下,第二相粒子析出開始時間與結(jié)束時間分別為10與160 s;隨著等溫弛豫時間的延長,第二相粒子析出數(shù)量逐漸增加,當弛豫時間超過析出結(jié)束時間后,析出物數(shù)量將不再增加而尺寸增加。試驗用Ti-IF鋼主要觀察到Ti N、Ti4C2S2、Ti C 3種析出物,Ti4C2S2與Ti C沉淀物的形狀和尺寸相差不多,無法從形狀和大小上來區(qū)分,易于沿奧氏體晶界或亞晶界析出,奧氏體亞晶的尺寸大約分布在0.1~0.4μm。900℃應變誘導析出物數(shù)量較800℃多,該結(jié)果與試驗鋼PPT曲線析出鼻子點溫度900℃是相符的。對于Ti-IF鋼,其熱軋工藝過程應有利于C,N化物的析出和聚集長大,最終形成粗大、稀疏的第二相粒子,因此宜采用"三低一高"快速大壓下的熱軋工藝制度,以提高Ti-IF鋼的深沖性能。
[Abstract]:The precipitation behavior of the second phase particles in the austenitic zone of titanium microalloyed IF steel was studied by stress relaxation test on Gleeble-3500 thermal simulator. The experimental results show that the stress relaxation curve shows three stages because of the pinning dislocation and grain boundary of the second phase particles. The precipitation-time-temperature curve of the test steel shows the typical "C" curve shape, the fastest precipitating nose point temperature is about 900 鈩，

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