Alternative TitleMicrostructure and Mechanical Properties of Welded Joint of a Fe-Cr-Ni-Mo Steel with High-Strength and High-Toughness
胡小锋; 姜海昌; 赵明久; 闫德胜; 陆善平; 戎利建
Source Publication金属学报
Abstract采用熔化极活性气体保护焊(MAG焊)对一种Fe-Cr-Ni-Mo高强高韧合金钢板进行多道次焊接,利用SEM、EPMA、TEM以及拉伸、冲击等实验研究了焊接接头的组织和力学性能。结果表明,焊缝金属由柱状晶和等轴晶组成,其中上部焊缝以柱状晶为主,而下部焊缝的等轴晶含量增加。焊缝上部因冷速较快形成回火马氏体组织;下部因合金元素含量较高,淬硬倾向较强,形成了粒状贝氏体组织。靠近焊缝的热影响区为较粗大的马氏体组织,其硬度最大(621 HV),明显高于母材(410 HV)。上部焊缝金属的硬度为365 HV,低于母材,而下部焊缝的硬度高于焊缝上部和母材,为450 HV。因此,焊接接头上部拉伸试样在焊缝处发生断裂,断裂强度为1109 MPa,而焊缝的下部拉伸试样在母材处发生断裂,断裂强度为1183 MPa。本实验用Fe-Cr-Ni-Mo合金钢的焊接接头强度较高,焊接强度系数不小于0.93,焊缝金属的冲击功为53 J。
Other AbstractHigh-strength steel has the advantages of high strength, low cost and good hot and cold workability, etc., which is widely used in various fields of national economy as engineering steel, such as bridge, vehicle, ship, pressure vessel and so on. As increasing strength, the plasticity and toughness of high strength steel have not meet the demand in some industrial areas, especially the low temperature impact toughness. Recently, a Fe-Cr-Ni-Mo steel with high-strength and high-toughness has been deve- loped and has been successfully used to prepare high pressure vessels. In this work, metal active gas (MAG) welding with multi-pass welding was used to join a Fe-Cr-Ni-Mo high-strength and high-toughness steel. The microstructure and fracture morphologies of welded joint are investigated by SEM, EPMA and TEM and the micro-hardness, tensile strength and Charpy impact energy are tested as well. The results show that the morphologies of welded metal (WM) consist of columnar crystal (CC) and equiaxed crystal (EC), where the upper WM is predominantly CC and the proportion of EC increases in the lower WM.The microstructure of upper WM is tempered martensite for the faster cooling rate. Because the higher content of alloying elements in lower WM improves the hardening tendencies, the lower WM is granular bainite. The heat affected zone near WM is coarsen martensite and has the highest hardness (621 HV), which is significantly higher than that of the base metal (BM) (410 HV). The hardness of the upper WM is 365 HV, which is lower than that of BM and the lower WM has higher hardness (450 HV). Therefore, the upper tensile sample of welded joint was broken in the WM and the fracture strength is 1109 MPa and lower than that of BM (1190 MPa). While the fracture position of lower tensile sample is in the BM and the strength is about 1183 MPa. The welded joint of experimental Fe-Cr-Ni-Mo steel has higher strength and the welding factor is not lower than 0.93. Moreover, the impact energy of WM is 53 J.
KeywordFe-Cr-Ni-Mo高强高韧合金钢 焊接接头 回火马氏体 粒状贝氏体 力学性能
Indexed ByCSCD
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Cited Times:4[CSCD]   [CSCD Record]
Document Type期刊论文
Recommended Citation
GB/T 7714
胡小锋,姜海昌,赵明久,等. 一种Fe-Cr-Ni-Mo高强高韧合金钢焊接接头的组织和力学性能[J]. 金属学报,2018,54.0(1.0):1-10.
APA 胡小锋,姜海昌,赵明久,闫德胜,陆善平,&戎利建.(2018).一种Fe-Cr-Ni-Mo高强高韧合金钢焊接接头的组织和力学性能.金属学报,54.0(1.0),1-10.
MLA 胡小锋,et al."一种Fe-Cr-Ni-Mo高强高韧合金钢焊接接头的组织和力学性能".金属学报
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