Influence of grain size and precipitation on hot ductility of microalloyed steels
Influence of grain size and precipitation on hot ductility of microalloyed steels
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DOI：
10.1179/mst.1986.2.11.1099
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发表时间：
1986-11
影响因子：
1.8
通讯作者：
D. Crowther;B. Mintz
中科院分区：
文献类型：
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作者：
D. Crowther;B. Mintz
通过将微合金钢（C-Mn-Al、C-Mn-V-Al和C-Mn-Nb-Al）加热到固溶温度以上并冷却到850°C的试验温度，测定了晶粒尺寸对这些钢的热塑性的影响。C-Mn-Al钢具有良好的热塑性，且与晶粒尺寸无关。动态再结晶容易发生，没有AlN析出的证据。显著的动态析出发生在含钒和含铌钢的拉伸试验过程中，但这并不随再加热温度而显著变化，只要析出物完全溶解即可。将这些钢中晶粒尺寸的影响与析出物的影响分离开来，表明晶粒尺寸从150 μm变化到300 μm时，面积值减少了15- 20%。还通过加热至850-1330°C范围内的温度并在850°C下进行拉伸测试来改变结晶分布。当在测试之前以细晶粒细化沉淀物的形式存在于γ晶界处时，AlN降低了C-Mn-Al钢的热塑性并延迟了动态再结晶的开始。通过提高再加热温度使动态再结晶发生而产生的较粗的沉淀物提供了改善的延展性。对于含铌和钒的钢，沉淀物分布是在一个粗糙的随机析出的形式给出了最好的热塑性。当加热到1100°C时，这些在含钒钢中发生，并且更通常地在含钒钢中在宽的温度范围内发生。当NbCN在试验前溶解时，含铌钢中的析出物分布最差，并且在试验期间在γ晶界和基体中以细小形式再析出。MST/490
The influence of grain size on the hot ducility of microalloyed steels (C–Mn–Al, C–Mn–V–Al, and C–Mn–Nb–Al) has been determined by heating them above their solution temperatures and cooling to the test temperature of 850°C. The C–Mn–Al steel showed excellent hot ductility which was independent of grain size. Dynamic recrystallization readily occurred and there was no evidence for AlN precipitation. Marked dynamic precipitation occurred during the tensile test for vanadium- and niobium-containing steels but this did not vary significantly with reheating temperature, provided complete dissolution of the precipitates had occurred. Isolating the influence of grain size from that of precipitation in these steels showed that a change in grain size from 150 to 300 μm reduced the reduction of area values by 15–20%. Precipitate distribution was also varied by heating to temperatures in the range 850–1330°C and tensile testing at 850°C. When present before testing at the γ grain boundaries in the form of a fine grain-refining precipitate, AlN reduced the hot ductility in the C–Mn–Al steel and delayed the onset of dynamic recrystallization. Coarser precipitates produced by raising the reheating temperature allowing dynamic recrystallization to occur gave improved ductility. For the niobium- and vanadium-containing steels, precipitate distributions which were in a coarse randomly precipitated form gave the best hot ductility. These occurred with the niobium-containing steel when heated to 1100°C and more generally in the vanadium-containing steel throughout a wide temperature range. The worst precipitate distribution occurred in the niobium containing steel when the NbCN was taken into solution before testing and reprecipitated in a fine form at the γ grain boundaries and within the matrix during the test. MST/490