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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Welding and Joining
Journal Basic Information
Journal DOI :
The Korean Welding and Joining Society
Editor in Chief :
Volume & Issues
Volume 3, Issue 2 - Nov 1985
Volume 3, Issue 1 - May 1985
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강 의 마찰용접 에 미치는 탄소당량 의 영향 - 동종강 에 대하여
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 1~9
In this study, the influence of carbon equivalents on friction welds of similar steels was investigated. Four types of steels with 15mm diameter tested in the wide range of carbon equivalents from 0.3 to 1.1 Main experimental results are summarized as follows : (1) Under the constant burn-off length, the friction time becomes longer with the increasing carbon equivalent, but the upset length shows no consistent tendencies. (2) Due to the recrystallization in the contact area, the maximum hardness occurs some away from the contact surface. And it increases almost linearly with the increasing carbon equivalent. (3) Even a steel with 1.1 C.E. can be friction welded to make defect-free welds. (4) With the increasing carbon equivalent, the bend angle and charpy impact value decrease very rapidly in the range from 0.3 C. E., but remain nearly unchanged for C. E. higher than 0.6. (5) Heat treatment of the base metals before welding has very little influence on the mechanical properties of welds. On the other hand, normalizing of the welds improves the bend angle and charpy impact value, but its effect becomes almost negligible, when the carbon equivalents are higher than 0.6.
알루미늄 의 常溫壓接 에 關한 硏究 I
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 10~15
Roughness of the surface to be welded is one of the important factors affecting the weldabilities on the pressure welding. The purpose of this study is to investigate the influences of the surface roughness upon the welding process and the weldability of pressure welds, using Aluminium AA1050 plates treated by various surface polishing The results obtained are as following. 1. The optimum welding deformation is about 38(%)-42(%) in cold pressure weld. 2. The grinding work on the weld surface is superior to milling and paper polishing. 3. Weld pressure must be beyond
in order that the bond may be achieved.
Cr - Mo鋼 熔接 後熱處理材 의 勞破壞 에 關한 硏究
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 16~26
Post weld heat treatment(PWHT), at more than 600.deg. C, is essential to remove residual stress and hydrogen in weld HAZ and improve fatigue characteristics. However, residual stress during PWHT is responsible for PWHT embitterment and it promotes precipitation of impurities to grain boundary. In this paper, the effect of stress simulated residual stress on fatigue failure was evaluated by fatigue test, microhardness test and fractograph. The obtained results are summarized as follows; (1) The fatigue crack growth rate(da/dN) of parent and heat treated parent was affected by microstructure due to heat treatment and it depended on stress intensity factor (.DELTA.k). (2) The fatigue strength of weld HAZ was dependent on applied stress during PWHT and da/dN after PWHT was slower than as-weld. (3) Softening amount of weld HAZ was bigger than any other due to PWHT. Hardness value of weld HAZ was affected by heat treatment under the applied stress of 10
, but beyond 20
it was increased by the applied stress rather than heat treatment. (4) Beyond the applied stress of 20
during PWHT, intergranular fracture surface was observed and its amount was increased with applied stress during PWHT. (5) Effect of applied stress during PWHT on aspect of fracture surface was larger rather than that on fatigue crack growth behavior.
Study on the cold pressure welding by upsetting
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 27~34
The mechanical properties and bonding mechanism of aluminum, copper and mild steel have been determined in cold pressure welding. The brittle cover layer to be established by scratch-brushing plays an important role in bond strength and has an influence on the threshold of deformation. The cold pressure welding was achieved at 54% of height reduction in A1-A1, 75% in Cu-Cu, 56% in Al-Cu, and 74% in Cu-steel. The height reduction at which the bond strength of weld interface was the same as the tensile strength of base metal should be over 76% in Al-Al, 82% in Cu-Cu, and 78% in Al-Cu.
A Study on Hot Straining Embrittlement of Subcritical HAZ in Steel Weldments
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 35~41
The fracture toughness of subcritical HAZ in the hot strained weldments of two structural steels(SB 41 and SA 537) has been investigated by COD test method and metallurgical study. The obtained results are summarized as follows; 1. The hot straining embitterment of subcritical HAZ depends on the hot straining amounts of notch tip, and the transition temperature(
) increases with the accumulated hot straining amounts(.SIGMA. vertical bar .delta.
vertical bar). 2. The fracture toughness of subcritical HAZ depends on materials and microstructure. The transition temperature(
) of subcritical HAZ in SB 41 is almost same as that of parent material, however in SA 537 the temperature is higher than that of parent and lower than that of transformed HAZ. 3. The subcritical HAZ in SA 537 shows a higher toughness at small amounts of hot straining (.SIGMA. vertical bar .delta.
The dynamic fracture toughness of aluminum alloy weld zone by instrumented charpy test
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 42~51
The dynamic fracture toughness, fracture characteristics, impact tension and tensile properties of Al-Mg-Si T5 alloy and Al-Zn-Mg T6 alloy respectively welded with filler metal of Alcan 4043 were investigated. The dynamic fracture toughness values were obtained rapidly and simply for the specimen of small size by using instrumented Chirpy impact testing machine. the testing temperatures of the specimen were a range of room temperature and-196.deg. C. The results obtained in this experiment are summarized as follows. With decreasing the testing temperatures, dynamic tensile stress and fracture load were increased, on the other hand the deflection and impact value showed decreasing tendency in order of base metal>HAZ>weld. Changes of total absorbed energy were more influenced by the crack propagation energy than the crack initiation energy. At the low temperatures, the unstable rapid fracture representing the crack propagation appeared for the specimens of Charpy press side notched in Al-Zn-Mg alloy, but it was difficult to obtain the unstable rapid fracture in Al-Mg-Si alloy. Because of the development of plastic zone at the notch root, it was difficult to obtain thevalid
value in Al-Mg-Si alloy. Therefore the fatigue cracked specimens were effective in both Al-Mg-Si and Al-Zn-Mg alloys. With decreasing the impact testing temperatures, specimens underwent a transition from dimple-type transgranular fracture to lamella surface-type intergranular fracture because of the precipitate at the grain boundaries, impurities and crystal structure of the precipitates.s.
Fracture mechanics approach to bending fatigue behavior of cruciform fillet welded joint
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 52~63
Fillet welded joints, specially in ship structure, are well known the critical part where stress concentrate or crack initiates and grows. This paper is concerned with the study of the behavior of fatigue crack growth t the root and toe of load carrying cruciform fillet welded joints under three points bending by the determination of stress intensity factor from the J-Integral, using the Finite Element Method. The stress intensity factor was investigated in accordance to the variation of the weld size (H/Tp). weld penetration (a/W) and plate thickness (2a'/Tp). As mixed mode is occurred on account of shearing force under the three points bending, Stern's reciprocal theory is applied to confirm which mode is the major one. The main results may be summarized as follows 1) The calculation formula of the stress intensity factor at the both of root and toe of the joint was obtained to estimate the stress intensity factor in the arbitrary case. 2) The change of stress field around crack tip gives much influence on each other at the roof and toe as H/Tp decreases. 3) Mode I is a major mode under the three points bending.
용접잔류응력과 그 제어
Journal of Welding and Joining, volume 3, issue 2, 1985, Pages 64~73