Peng HE
,
Jicai FENG
,
Jiecai HAN
,
Yiyu QIAN
材料科学技术（英文）
A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and maximum inherent strain gmax is given. The model T.E.P-Tav-hardness calculation is proposed to predict distribution of inherent strains in T type welding structure. By T.E.P-Tav-hardness calculation, distribution of longitudinal inherent strains can be predicted in T type welding structure, and calculation and experimental results are consistent.
关键词:
Inherent strain
,
null
,
null
Xin MA
,
Yiyu QIAN
,
Hongyuan FANG
,
F. Yoshida
材料科学技术（英文）
By temperature normalization of the concept of equivalent damage stress proposed by Lemaitre, a new concept of relative damage stress has been put forward as the dominant mechanical factor for the failure of soldered joints under temperature cycling. Finite element numerical simulation results showed that the highest value of relative damage stress occurred at the high temperature hold time during temperature cycling history.
关键词:
Hongyuan FANG
,
Li WANG
,
Yiyu QIAN
材料科学技术（英文）
Fatigue crack propagation life of ball grid array (BGA) soldered joints during thermal cycling loading was investigated by fracture mechanics approach using finite element analysis. The relationships between the strain energy release rate (G) acid crack size (a), thermal cycle numbers (N) can be derived. Based on the relationships, fatigue life of the soldered joints was determined. The results showed that crack propagation life was higher than crack initiation life. Therefore, it appears that it is more appropriate to predict the fatigue life of soldered joints using the fracture mechanics method.
关键词:
LI Chong-wei
,
CHENG Guo-guang
,
WANG Xin-hua
,
ZHU Guo-sen
,
CUI Ai-min
钢铁研究学报(英文版)
A mathematical model in present study has been established to investigate the effect of Rheinstahl Heraeus (RH) blow argon mode on the decarburization rate in ultra-low carbon steel refining based on the RH equipment of Shougang Qian′an Iron and Steel Co Ltd (SQISCO). The calculated results show that the increase of argon flowrate promotes the carbon elimination from argon gas bubble surface, molten steel free surface in vacuum as well as splash droplet surface, while reduces that from the interior of liquid steel. It has been found the critical turning point of flowrate ascension is at the 5th minute and the optimum blow argon flowrate in later stage is 2100 L/min in accordance with the 2 stages argon blow mode, which have been confirmed in the commercial production in SQISCO.
关键词:
RH
,
vacuum
,
mathematical model
,
argon flowrate
,
decarburization
