Effect of quenching and partitioning process on texture and properties of high strength Q&P steel
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摘要: 对试验用淬火配分（Quenching and Partitioning，Q&P）钢在一步淬火配分工艺中不同淬火温度（220 、260 、300 ℃）和淬火时间（60 、120 、180 s）下组织、织构、力学性能及拉伸断口特征进行研究. 结果表明：试验用Q&P钢在一步淬火配分中获得的最大残余奥氏体体积分数为7.12%；随着淬火温度升高，板条马氏体的宽度增大；随着淬火温度和配分时间升高，织构的最大强度逐渐降低，抗拉强度逐渐减少；屈服强度和延伸率呈相反的变化趋势.Abstract: The microstructure, texture, mechanical properties and tensile fracture characteristics of quenching and partitioning (Q&P) steel were studied at different quenching temperatures (220, 260, 300 ℃) and quenching times (60 , 120 , 180 s) in one-step Q&P process. The results show that the maximum volume fraction of residual austenite（RA）obtained in one-step Q&P was 7.12%. With the increase of quenching temperature, the width of lath martensite increased. With the increase of quenching temperature and partition time, the maximum strength of the texture decreased, so did the tensile strength, while the yield strength and elongation showed opposite trends.
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图 1 淬火温度和淬火时间变化的一步淬火配分工艺
Figure 1. 1-Step Q&P process of varying quenching temperature and quenching time
图 3 Q&P钢在不同淬火处理之后的金相显微图（1-step）
Figure 3. Metallographic micrographs of Q&P steel after different quenching temperatures
(a) 900 ℃ × 90 s + 220 ℃ × 120 s (b) 900 ℃ × 90 s + 260 ℃ × 120 s (c) 900 ℃ × 90 s + 300 ℃ × 120 s
图 4 Q&P钢在不同淬火处理之后的SEM图（1-step）
(a) 900 ℃ × 90 s + 220 ℃ × 120 s (b) 900 ℃ × 90 s + 260 ℃ × 120 s (c) 900 ℃ × 90 s + 300 ℃ × 120 s
Figure 4. SEM micrographs of Q&P steel after different quenching temperatures
图 5 配分120 s不同淬火样的XRD图（1-step）
Figure 5. XRD pattern of different quenching samples with 120 s
图 6 Q&P钢在不同淬火温度下配分120 s时ODF图
Figure 6. ODF pictures of Q&P steel at different quenching temperatures with patitioning time of 120 s
图 7 不同淬火温度下的Q&P钢取向线的变化,
Figure 7. Changes of orientation line at different quenching temperatures
图 8 Q&P钢淬火到260 ℃保温60、120、180 s的ODF图
Figure 8. ODF pictures of Q&P steel quenched to 300 ℃ isothermy 60, 120 and 180 s
图 9 不同配分时间下的Q&P钢取向线的变化
Figure 9. The variation of orientation line for different partitioning time
图 10 不同淬火配分工艺下的应力−应变曲线和拉伸性能
Figure 10. Stress-strain curves and tensile properties under different quenching and partitioning processes
表 1 试验用Q&P钢的主要成分
Table 1. Main chemical composition of test Q&P steel
元素 C Si Mn Al Fe 质量分数/% 0.23 1.55 1.92 0.04 余量 
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表 2 试样中残余奥氏体体积含量及其含碳量
Table 2. Volume content and carbon content of retained austenite in samples
试样 RA/% RA中C含量/% 300 ℃/s + 120 s 6.82 1.20 260 ℃/s + 120 s 7.12 1.26 220 ℃/s + 120 s 4.28 1.29
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