Technology for repairing surfacing of piston rod of super large marine diesel engine

Abstract

The invention discloses a technology for repairing surfacing of a piston rod of a super large marine diesel engine, and the technology can carry out the deep repair of the surface of the piston rod. The adopted surfacing process is as follows: flaw detection and straightening are carried out on the piston rod, turning machining is carried out on the surface of the piston rod to remove a defect layer, and individual deeper cracks are manually removed by grinding; fire whirl is used for heating the piston rod twice, the first heating is carried out till 200 DEG C-250 DEG C, the heating is stopped, the race rotation is carried out for 30 minutes, the second heating is further carried out after the temperature difference between the interior and the exterior is reduced, and a surfacing machine tool is rotated after reaching 250 DEG C-300 DEG C; submerged arc welding is used for rotating dual heads of the surfacing machine tool and a 2Cr13 flux-cored welding wire for carrying out the simultaneous surfacing, and asbestos cloth is used for wrapping and keeping the temperature during the welding process; the piston rod wrapped by the asbestos cloth for slow cooling after the surfacing achieves the size requirement, when the temperature is decreased to be lower than 100 DEG C, the piston rod wrapped by the asbestos cloth is vertically placed till the temperature is decreased to the room temperature, and then the temperature-keeping cloth is removed. The surface of the piston rod after the repair by employing the method has no weld defects, the piston rod fully meets the performance requirements, and the cost is only about one fifth of the cost for fabricating a new piston rod.

Description

technical field [0001] The invention relates to a surfacing welding method, in particular to a surfacing welding repair technology for a piston rod of an ultra-large ship diesel engine. It can restore the function of the worn piston rod. Background technique [0002] As an important part of marine diesel engine, the piston rod has complicated production process and great processing difficulty, and its quality is directly related to the quality of the whole machine. NSD company's RTA84T low-speed high-power diesel engine has a power of 20813kw~37464kw (27900 horsepower~50220 horsepower). During the use of the piston rod, its surface is worn out, accompanied by defects such as bruises, pits, pits, and cracks. The direction of its axis may be bent. If a new piston rod is replaced, the cost ranges from hundreds of thousands to hundreds of thousands of yuan, and the cost of repairing a piston rod is only 1 / 5 to 1 / 3 of the cost of a new one. Therefore, for low-speed and high-pow...

AI Technical Summary

Problems solved by technology

Since the chrome plating and iron plating layers are relatively thin, this method is only suitable for the repair of defects such as shallow bruises and cracks on the piston rod. It cannot deal with deeper defects on the piston rod, and the surface roughness and cleanliness of the workpiece before plating Higher requirements, increased repair costs

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