CAJ | 학술논문

利用Gleeble 3500热模拟实验机研究热冲压成形超高强钢B1500HS快速加热过程中的奥氏体化. 研究结果表明随着升温速率的增加, 相变温度Ac1, Ac3和奥氏体均匀化温度逐渐升高, 这与用JMatPro热力学计算的TTA图结果基本吻合. 当奥氏体化温度低于940℃时, 在保温10 min以内, 不同升温速率下奥氏体晶粒尺寸均可保持在5~15μm范围内. 当奥氏体化温度更高时, 奥氏体晶粒快速长大, 升温速率越大, 长大的潜能也越大. 碳化物的固溶受升温速率, 奥氏体化温度和保温时间的影响. 在940℃下保温5 min碳化物能够全部固溶. 研究结果还证明, 在足够快速冷却且未变形的情况下, 碳化物的固溶程度对淬火马氏体硬度几乎不产生任何影响.
이용Gleeble 3500열모의실험궤연구열충압성형초고강강B1500HS쾌속가열과정중적오씨체화. 연구결과표명수착승온속솔적증가, 상변온도Ac1, Ac3화오씨체균균화온도축점승고, 저여용JMatPro열역학계산적TTA도결과기본문합. 당오씨체화온도저우940℃시, 재보온10 min이내, 불동승온속솔하오씨체정립척촌균가보지재5~15μm범위내. 당오씨체화온도경고시, 오씨체정립쾌속장대, 승온속솔월대, 장대적잠능야월대. 탄화물적고용수승온속솔, 오씨체화온도화보온시간적영향. 재940℃하보온5 min탄화물능구전부고용. 연구결과환증명, 재족구쾌속냉각차미변형적정황하, 탄화물적고용정도대쉬화마씨체경도궤호불산생임하영향.
Austenization of hot stamped ultrahigh steel B1500HS during heating at high rate is analyzed with Gleeble 3500 simulation testing machine. The result reveals the phase transition temperature Ac1 and Ac3 and homogenizing temperature of austenite components rise gradually with the increase of heating rate. This matches the TTA diagram that is calculated with JMatPro thermodynamics software. When austenization temperature is below 940 ℃and is hold for 10 minutes or less, the austenite gain obtained at different heating rates are sized in the range of 5~15μm. When austenization temperature increases higher than 940℃, the austenite grain grows rapidly, and higher the heating rate is, higher the growth potentiality becomes. The solid solution of carbides depends on heating rate, austenization temperature and soaking time. Solid solution of all carbides can be achieved when the temperature is hold at 940℃for 5 minutes. The carbides solution degree has little effect on the quenching hardness of martenite at high cooling rate without deformation.