Electric heating – Metal heating – By arc
Patent
1994-10-28
1996-08-27
Shaw, Clifford C.
Electric heating
Metal heating
By arc
B23K 900
Patent
active
055503470
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of reducing welding distortion in one side welding for joining plates. More particularly, the present invention provides a method of reducing welding distortion in one side welding for joining plates, by which welding distortion is reduced when welding is executed under optimal welding conditions in multi-electrode welding.
DESCRIPTION OF THE PRIOR ART
According to the prior art, the following one side welding methods for joining plates are provided. As shown in FIG. 2, steel plates 1, 1' to be welded are butted against each other, and a tack-welded bead, the height of which is the same as the wall thickness of the plates to be welded, is provided in a groove, especially in a groove of the end portion of welding. Alternatively, a tab, the thickness of which is the same as the wall thickness of the plates to be welded, is tack-welded at the end portion of welding so that the height of the bead can be the same as the wall thickness. In this way, the steel plates 1, 1' to be welded are sufficiently bound before the start of welding so as to reduce welding distortion. Alternatively, the following method is provided, in which the plates to be welded are heated by means of gas burners in the process of welding, so that the thermal history is controlled for reducing welding distortion. However, according to the conventional methods in which a high restraining force is applied to the steel plates to be welded using the tack-welded bead or tab, a heavy burden is imposed for preparation before the start of welding, and further it is necessary to repair the plates after the completion of welding, which causes a problem from the viewpoint of enhancing the efficiency of welding. Also, the method of controlling the thermal history using gas burners is disadvantageous in that the welding apparatus becomes large and it is difficult to enhance the welding efficiency.
According to the prior art for reducing welding distortion in one side welding for joining plates, it is a primary object to prevent the occurrence of end cracks which occur at the end of a welded bead in the process of welding. Ando et al. disclosed that these end cracks were caused by welding distortion in the process of welding (Magazine of Welding Society Vol. 30(1970), NO. 8, P792). After that, various investigations were made to investigate the distribution of stress caused in the process of welding (Sato et al.: Theses of Japanese Ship Building Society, Vol. 136 (1974), P441, and Fujita et al.: Theses of Japanese Ship Building Society, Vol. 133 (1973), P267). According to the results of these investigations, in order to prevent the occurrence of end cracks, it is necessary to reduce welding distortion in the process of welding. However, the method for accomplishing the object of reducing welding distortion is limited to the one in which the tack-welded bead or tab is used as described before.
On the other hand, the prior art of the method for preventing end cracks is summarized by Kamichika et al. (Magazine of Japanese Construction Association (JSSC), Vol. 10 (1974), No. 101, P35). According to the prior art summarized by Kamichika et al., the methods in which tack-welded bead and tabs were used were reported in order to prevent the occurrence of distortion, and further a method of restraining the end portion of welding by a hydraulic jack was reported. These conventional techniques aim at reducing welding distortion in the process of welding by strongly restraining steel plates to be welded. According to the method in which steel plates are heated by gas burners, it is impossible to reduce welding distortion to such an extent that the occurrence of end cracks can be prevented.
Japanese Unexamined Patent Publication No. 53-51153 discloses a method in which an amount of welding heat input is reduced at the end portion of plates to be welded and an amount of bead is supplied to make up for the lacking bead in the process of repairing work.
Recently, an investigation has been reported, in which
REFERENCES:
patent: 1512787 (1924-10-01), Morton
patent: 2106987 (1938-02-01), Powell
patent: 2449082 (1948-09-01), McCabe
patent: 4046988 (1977-09-01), Okuda et al.
patent: 5214265 (1993-05-01), Pollack
Magazine of Welding Society, vol. 39, No. 8, p. 792 (Aug. 1970); (No Translation).
Thesis of Japanese Ship Building Society, vol. 136, p.441 (Nov. 1974); (No Translation).
Thesis of Japanese Ship Building Society, vol. 133, p.267, (May 1973); (No Translation).
Magazine of Japanese Conctraction Association (JSSC), vol. 10, No. 101, p.35 (May 1974); (No Translation).
Thesis of Japanese Ship Building Society, vol. 171, p.395 (May 1992). (No Translation).
Horii Yukihiko
Kasuya Tadashi
Miyazaki Tateo
Shinada Koichi
Hitachi Zosen Corporation
Nippon Steel Corporation
Shaw Clifford C.
LandOfFree
Method of reducing welding distortion in one side welding for jo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of reducing welding distortion in one side welding for jo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of reducing welding distortion in one side welding for jo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1057563