钒含量对Ti-V微合金钢CGHAZ韧性影响研究

Effect of Vanadium Content on Toughness in the Coarse-Grained Heat Affected Zone of Ti-V Microalloyed Steels

现阶段'Ti氧化物冶金+V微合金化'复合技术用于研发大线能量焊接用钢已引起人们的广泛关注,这种复合技术能够充分利用在Ti的氧化物上析出的Ti、V碳氮化物粒子诱导焊接粗晶热影响区大量针状铁素体形核,改善CGHAZ韧性。本研究从运用Thermo-Calc热力学软件定量计算第二相颗粒固溶析出规律入手,考察了Ti、V、O、N等元素构成的氧化及碳氮化夹杂物在诱导AF形核中的关键作用。与此同时,在研究中也利用了热力模拟试验机、力学测量设备、高倍电镜等,对V含量为0、0.05%、0.1%的Ti-V微合金钢进行大线能量焊接、力学性能测量及形貌分析。通过分析试验结果得出V元素在提高Ti-V微合金钢强度和CGHAZ韧性的一般规律,并进一步阐述了Ti-V微合金钢CGHAZ中析出夹杂物诱导AF形核机制。

This composite technology of Ti-oxide metallurgy and V-microalloying for the research and development of high energy input welding steels has aroused extensive attention in the present stage. This carbon and nitride particles precipitated on the non-metallic inclusions by the composite technique, This inclusions can induce massive nucleation of the acicular ferrite in the coarse-grained heat affected zones, So as to improve the toughness of the CGHAZ. The quantitative calculation of the solid solution and precipitation of second phase particles is carried out by using the Thermo-Calc thermodynamic software. The key role of Ti, V, O, N and other elements in the formation of AF nucleation by oxidation and carbon nitride inclusions is further investigated. Meanwhile, the Ti-V microalloyed steels with V content of 0, 0.05% and 0.1% is subjected to high energy welding, The Mechanical properties and morphology is analyzed by using the thermal simulation testing machine, mechanical measuring equipment, high power electron microscope and other equipment. Through the analysis of the experimental results, it is concluded that the general law of V element in improving the strength and the CGHAZ toughness of Ti-V microalloyed steels, and further expounded the mechanism of inducing AF nucleation in the CGHAZ of Ti-V microalloyed steels.