An investigation of oxyacetylene welding and cutting blowpipes, with especial reference to their design, safety, and economy in operation by Johnston Robert Smith 1885-

Author:Johnston, Robert Smith, 1885-
Language: eng
Format: epub
Tags: Welding, Metal-cutting
Publisher: Washington, Govt. Print. Off.
Published: 1922-03-25T05:00:00+00:00

facturers for cutting particular thicknesses of metal were not suitable for the work intended. One of the main troubles seemed to be that the majority of the blowpipes were operated with preheating flames of too high intensity.

Throughout the entire series of cutting tests all blowpipes were operated similarly, that is, at least one of the gas control valves for the preheating flames was at full opening, the preheating flames were adjusted to neutral with the oxygen cutting valve at full opening, and all cutting operations were started with this latter open. Some criticism of this procedure developed from time to time, but throughout the entire series of tests it was found that at no time were any detrimental results produced, and that even on cuts as heavy as 16 inches no trouble was found in starting with the oxygen cutting valve open. This method was adopted to insure the maximum capacity of the blowpipe throughout the entire test period, and, further, to enable the maintenance of accurate pressures throughout the test and insure accurate data as to the maximum gas consumption during the cutting operation.

Test 9, cutting for maximum thickness, was originally conducted with the idea of submitting the blowpipe to a test for the maximum thickness specified by the manufacturer as permissible for his blowpipe. It was found during the course of the investigation that the great majority of the blowpipes would not successfully cut the so-called maximum thickness specified by the manufacturers. Experience during the investigation seemed to indicate that the probable maximum commercial limit for economic heavy cutting operations when the cut is made in one direction only with an ordinary stock blowpipe, lay in the neighborhood of 10 inches. It was therefore decided that all blowpipes should be submitted to the same maximum or heavy cut. A cut in material 10 inches in thickness, of 12 to 18 inches in length was therefore made as a supplementary heavy cut test for each blowpipe.

The tests for maximum thickness of cut were made by hand. On account of the possibility of damage to the gage-board equipment caused by heavy slag showers from pockets, etc., produced during cutting, this test was conducted out of doors. The original tests for maximum thickness were therefore made on different days with the temperature of the metal varying from 35 to 68° F. After the decision had been made to submit all blowpipes to cutting tests of identical thickness, it was decided to minimize the effects of varying temperature as much as possible on the heavy cut by making all cuts during the course of one or two days. By

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