|
A Ti6Al4V countersunk head bolt with Φ6 mm occurred perforations in the bolt head failure in the tensile strength testing, and its tensile strength decreased by 3%-5% on average. Therefore, macro and micro fracture qualities, microstructure and chemical composition of the failure parts were analyzed by SEM, EDS, OEM and other means, and the micro cracks were found inside the bolt head. The result shows that due to the large clearance of the raw material cutting machine, material incision occurs burr in the process of cutting, and then the burr is brought into the head end to form a micro cracks in the process of block upsetting so as to decrease the strength of bolt head finally. By adjusting the clearance of the raw material cutting machine, micro cracks at the bolt head can be significantly reduced or eliminated. In addition, the head forming height can be raised to meet the use requirements by turning processing to eliminate transverse crack eventually.
|
|
［1］Chishti M，Wang C H，Thomson R S, et al. Numerical analysis of damage progression and strength of countersunk composite joints [J]. Composite Structures, 2012, 94(3): 643-653.
［2］李轩颖,徐雪峰,付春林, 等. 某型飞机钛合金钣金件热冲压成形工艺参数优化[J]. 塑性工程学报,2017,24(1):92-97.Li X Y, Xu X F, Fu C L, et al. Optimization of hot stamping process parameters for a certain type of aircraft titanium alloy sheet metal parts [J]. Journal of Plasticity Engineering, 2017, 24(1): 92-97.
［3］Egan B，McCarthy C H，McCarthy M A，et al. Stress analysis of single-bolt single lap counter sunk composite joints with variable bolt-hole clearance [J]. Composite Structures，2012,94(3): 1038-1051.
［4］王国峰，赵相禹，孙超，等.TC4钛合金中空叶片扩散连接-超塑成形技术[J]. 锻压技术，2015，40（4）：49-53.Wang G F，Zhao X Y，Sun C，et al. DB-SPF technology of hollow blade for TC4 titanium alloy [J]. Forging & Stamping Technology, 2015,40(4): 49-53.
［5］刘宝胜，吴为. TNW700钛合金热成形极限试验研究[J]. 锻压技术，2015，40（10）：20-23.Liu B S, Wu W. Experimental research on thermal forming limit of TNW700 [J]. Forging & Stamping Technology, 2015, 40(10): 20-23.
［6］Goutam D Revankar, Raviraj Shetty, Shrikantha S, et al. Analysis of surface roughness and hardness in ball burnishing of titanium alloy [J]. Measurement, 2014, 18(3):321-327.
［7］Huhne C, Zerbst A K, Kuhlmann G，et al. Progressive damage continuous degradation models [J]. Composite Structures, 2010, 29(1): 189-200.
［8］ Yoichi Yamashita, Yusuke Ueda, Hiroshi Kuroki. Fatigue life prediction of small notched Ti-6Al-4V specimens using critical distance [J].Engineering Fracture Mechanics, 2010, 77:485-490.
［9］刘章光,李建辉,李培杰, 等. Ti-55钛合金板材的超塑性变形及组织演变[J]. 稀有金属,2016,38(6):284-291.Liu Z G, Li J H, Li P J，et l.Superplastic deformation and microstructure evolution of Ti-55 alloy sheet [J]. Chinese Journal of Rare Metals, 2016, 38(6):284-291.
［10］金和喜,魏克湘,李建明,等. 航空用钛合金研究进展[J]. 中国有色金属学报, 2015, 25(2): 280-292.Jin H X, Wei K X, Li J M, et al. Research development of titanium alloy in aerospace industry [J]. The Chinese Journal of Nonferrous Metals, 2015, 25(2):280-292.
|
Copyright Forging & Stamping Technology.All rights reserved