70 mm厚锻造及轧制镍基合金690板材热塑性和热裂纹敏感性（英文）

Thermal Ductility and Hot Cracking for 70 mm Thick Forge Plate and Rolling Plates of Nickel Alloy 690

利用光学显微镜、扫描电镜及Gleeble 1500热模拟机,分析70 mm厚锻造及轧制镍基合金690板材的热塑性及热裂纹敏感性。结果表明:锻造和轧制板材均有优异的热塑性,同种材料试样表层的热塑性高于试样中心位置的热塑性。模拟加热过程发现,较低温度条件下轧制板材的热塑性高于锻造板材的热塑性,随着温度的升高锻造板材的热塑性高于轧制板材的热塑性。模拟冷却过程发现,锻造板材比轧制板材具有更好的热塑性。热模拟试样的断面较为光滑,部分位置出现熔融现象。横向可调拘束裂纹敏感性试验结果显示,锻造及轧制镍基合金690板材具有较高的热裂纹敏感性。随着施加应变的增大,热裂纹的数量增多且长度增加。

The thermal ductility and hot cracking sensibility of the forge and the rolling plates with 70 mm in thickness were studied by optical microscope(OM), scanning electron microscope(SEM), and Gleeble 1500 thermal simulation equipment.The results show that the forge and the rolling plates both have excellent thermal ductility;the samples taken from surface position present higher thermal ductility than those taken from middle position of the same plate. During the heating process,the rolling plate has higher thermal ductility than the forge plate at the lower temperature. With the increase of the temperature,the forge plate is characterized by higher thermal ductility compared with the rolling plate. However, during the cooling process, the forge plate indicates higher thermal ductility than the rolling plate. The fracture position features more smoother morphology, even the melt phenomenon exists at some positions. Besides, high hot cracking sensitivity appears in both the forge and rolling nickel alloy 690. And the crack number and length increase with the applied strain increasing.