Stern shaft sleeve lengthening process

Abstract

The invention discloses a stern shaft sleeve lengthening process. The stern shaft sleeve lengthening process includes the following steps that (1), a groove is prepared, specifically, a V-shaped groove is adopted; (2), assembly is carried out, specifically, a stern shaft sleeve is clamped by a ring clamp; (3), preheating is carried out; (4), positioning welding is carried out, specifically, two welders symmetrically perform positioning welding in the 6 o'clock position and the 12 o'clock position of a circumferential seam, and the 3 o'clock position and the 9 o'clock position of the circumferential seam respectively, and the length of each tack weld is not less than 200mm; (5), filling welding is carried out, specifically, the two welders start welding at the same time, one performs welding from the 6 o'clock position to the 9 o'clock position to the 12 o'clock position, and the other performs welding from the 6 o'clock position to the 3 o'clock position to the 12 o'clock position, thecircumferential seam is hammered in the 6 o'clock position immediately after the welding of the first three layers, and multi-pass welding is started from the fourth layer; (6), post heating is carried out; and (7), after the completion of the post heating of the circumferential seam, a next pipe section is hoisted to a jig frame, steps (2) to (6) are repeated, and then lengthening into a whole pipe is carried out. The stern shaft sleeve lengthening process is convenient for assembly. The weld seam has no defects and the internal stress is small. The concentricity of the stern shaft sleeve after lengthening can meet the design requirements.

Description

technical field [0001] The invention relates to the field of welding, in particular to a process for lengthening a stern shaft casing. Background technique [0002] A stern shaft bushing with a total length of 10190mm is composed of 5 parts, including the stern bearing seat, the rear shaft bushing, the middle bearing seat, the front shaft bushing, and the bow bearing seat. These 5 parts are sequentially connected into a whole stern shaft Shaft sleeve. The bearing seat is a chrome-molybdenum alloy forged steel with a carbon equivalent of 0.7, which is a difficult-to-weld material. The shaft sleeve is a carbon-manganese steel pipe with a carbon equivalent of 0.45. The outer diameter of the bearing seat is 610mm, the thickest section is 138.5mm, and the thinnest section is 105mm. The outer diameter of the shaft sleeve is 610mm, and the wall thickness is 31.8mm. After the extension is completed, the allowable deviation of concentricity within the range of 10190mm in the total ...

AI Technical Summary

Problems solved by technology

[0003] (1) The pipe diameter is large, the pipe wall is thick, and the pipe is long, so it is difficult to assemble and align;

[0004] (2) It is difficult to weld chrome-molybdenum alloy forgings and carbon-manganese steel, and welding cracks are easily generated;

[0005] (3) The near root of the weld is easily deformed during welding, and the concentricity of the stern shaft casing is difficult to guarantee

[0006] (4) Welding will produce a large welding stress. The chrome-molybdenum alloy forging steel itself has a huge compressive stress. These stresses are concentrated in the welded joints, which affect the stable bearing capacity of the welded joints. to tear

[0007] At present, the main method of welding this kind of pipe fittings is butt joints, using argon arc welding or manual arc welding, and tempering treatment at 550 ° C for many hours after welding, but the above problems cannot be avoided

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