This research has been conducted for the purpose of investigating the fundamental characteristics in the contraction and residual stresses occured in patch-weld. The following three cases were studied. (i) Circular groove bead weld by multilayer sequence. (ii) Circular patch-weld by multilayer sequence. (iii) Circular patch-weld by block sequence. The size of specimen and welding sequence are shown in Fig. 1 and Table 1. The measurement of radial contraction (by measuring machine, ) and reaction stress occured in the central part of specimen (by electric resistance wire strain gauges) were conducted after the welding of each layer. The results obtained so far are summarized as follows : - 1) Form of radial contraction Form of radial contraction is remarkably affected by welding procedures. In order to investigate the effect of welding procedures on the form of contraction, the radial contraction is classified into three components as uniform contraction, relative translation between-welded patch and outer ring, and contraction of higher order as shown in E_q . (1) and Fig. 7. The effect of welding procedures on contraction are analysed using two parameters such as “unfairness index of shrinkage” δ and “apparent shrinkage energy” U defined by E_q . (2) and (2) '. The magnitude of translational motion, the contraction of higher order and therefore the value of δ took the highest values in the specimen patch-welded by block sequence. But in this specimen the lowest values of uniform contraction and U were obtained. 2) Relation between radial contraction and weight of deposited metal. Relation between logarithm of weight of electrode consumed per unit weld length log w and mean contraction u_r is shown in Fig. 6. The linear relation between log w and u_r , . holds good in following cases : - (i) Groove bead weld …all stages of welding (ii) Patch-weld by multilayer sequence …after the completion of 1st layer (iii) Patch-weld by block sequence. …only for the increase of contraction in the welding of each block These facts show that the linear relation of this kind generally holds good when the multilayer welding is taken into consideration. 3) Change of reaction stress during welding Change of reaction stress during welding is shown in Fig. 10. The most ununiform distribution of strain was obtained in the specimen welded by block sequence. 4) Comparison between block and multilayer sequence The block sequence seems to be more suitable than multilayer sequence to reduce, , the residual stress ocured in patch-welding, mainly from the view point of reducing the total strain energy stored in the specimen. The residual stresses after the completion of welding were also measured. These data will be reported soon later.