The influence of hot forging conditions on the microstructure and mechanical properties of two microalloyed steels
The influence of hot forging conditions on the microstructure and mechanical properties of two microalloyed steels
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DOI：
10.1016/s0924-0136(01)00599-4
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发表时间：
2001-06-15
影响因子：
6.3
通讯作者：
Eghbali, B
中科院分区：
文献类型：
--
作者：
Jahazi, M;Eghbali, B
为了取代淬火和回火的锻造零件，并消除这种方式昂贵和耗时的操作，开发了一种工业锻造工艺，以评估形变热处理参数对V和V-Ti微合金钢的组织和力学性能的影响。在1200 ℃等温淬火后，在2500 t机械压力机上锻造微合金钢坯料。锻造进行了三个步骤（辊锻，成型和精加工）后，根据不同的时间表，以研究冷却速度对拉伸，夏比V型缺口，冲击和硬度值的影响试样冷却。铁素体晶粒尺寸，珠光体团尺寸，片间距，铁素体/珠光体百分比和板条厚度作为锻造条件的函数的变化，其次是由光学显微镜。结果表明，随着冷却速度的增加，钢的强度和韧性都有所提高。在这些条件下，显微组织主要由非铁素体/珠光体转变产物组成。在相同锻造条件下，含Ti微合金钢比V钢具有更好的强韧性。在经典形核理论的框架内讨论了结果，并确定了达到最佳强韧比和显微组织的最佳锻造条件。(C)2001 Elsevier Science B. V.保留所有权利。
With the aim of replacing quenched and tempered forging parts and eliminating by this way costly and time consuming operations; an industrial forging procedure was developed to evaluate the influence of thermomechanical processing parameters on the microstructure and mechanical properties of V and V-Ti microalloyed steels. After austenitization at 1200 degreesC the microalloyed steel billets were forged in a 2500 t mechanical press. Forging was performed in three steps (roll forging, molding and finishing) after which the specimens were cooled according to various schedules in order to study the influence of cooling rate on the tensile, charpy V-notch, impact and hardness values. The variation of ferrite grain size, pearlite colony size, interlamellar spacing, ferrite/pearlite percentage and lath thickness as a function of forging conditions was followed by optical microscopy. The results indicated that by increasing the cooling rate both the strength and toughness increase. Under these conditions the microstructure is mainly composed of non-ferrite/pearlite transformation products. It was also found that under similar forging conditions the Ti-containing microalloy steel leads to a better strength/toughness combination than thr V steel. The results are discussed in the framework of classical nucleation theory and the optimum forging conditions to reach the best strength/toughness ratio and microstructure for each steel were determined. (C) 2001 Elsevier Science B.V. All rights reserved.