From the practice of ship repair of ship boilers

The most time-consuming and responsible work in the repair of steam ship boilers is the repair of fire parts, such as; fire pipes, walls of fire chambers, rear pipe grilles. The repair of the rear pipe grilles is mainly reduced to their partial or complete replacement or re-installation of glasses. The pipe gratings are changed completely when defects such as warping, cracks, and changes in the structure of the metal over the entire area of the pipe grating are detected. Partial replacement of the pipe grating with the installation of individual diamond patches is performed when these defects are detected only in any part of it.

Simplification of work on the complete or partial replacement of pipe gratings is provided by the use of electric welding instead of riveting, but almost all steam boilers on working ship installations of the People's Commissariat of Marine Fleet are made of riveted construction, and not all-welded, so we have to reckon with possible disorders of riveted seams.

The illustrations show the usual execution of changing the rear pipe grid of steam boilers using electric welding. The old pipe grate was cut out by autogen. The disadvantage of this method is that large zigzag docking lines complicate their careful fitting. Large stretches of electric welds cause large shrinkage deformations in the metal, as well as a violation of the strength and density of adjacent rivet seams.

To facilitate the work on replacing the pipe grid, the fitting area of the pipe grid and shrinkage stresses should be minimized, electric welding when welding the rear pipe grid should not violate the density of rivet joints.

The method of repairing the rear pipe grate of a steam boiler, used at the Narkommorflot ship repair plant in the conditions of the Patriotic War, is shown in the documentation for the article. Its main advantage is the minimum length of the electric weld between the points of the pipe grid. Compared to the previous repair method, the length of the weld between the glasses is 5 times less. Shrinkage stresses due to the small length of the seam are introduced to a minimum. The shortening of the seam simplified the fitting of the pipe grate in place, too, by about 5 times. The repair technology by this method was adopted as follows: the rear pipe grate was cut out of a boiler with dimensions 10 mm smaller on the side around the perimeter for subsequent edge stripping and fitting of a new pipe grate.

To prepare for the installation and preparation of the patch, the edges of the cutout of the pipe grate on the water side were cut into a V-shaped seam (see section according to "SS"). According to the cutout in the grid, templates were made that provide gaps in the upper part and in the sides between the new patch and the remaining contour within 3-3.5 mm. The gaps in the lower parts of the grid were left in 1 mm. No gaps were left at the junction of the patches with each other.

According to the manufactured templates, the patch was prepared and cut with the necessary processing and flexible flanging according to the template in place. Flanging was performed after heating according to a template from a heat pipe. Wenn du dein TikTok-Konto vergrößern möchtest, gibt es keinen besseren Ort als TikTokFollowerKaufen.DE