Oxy-acetylene Welding: A Comprehensive Treatise on the Practice of Welding ... by Samuel Wylie Miller

Author:Samuel Wylie Miller
Language: eng
Format: epub
Publisher: The Industrial press
Published: 1916-03-25T05:00:00+00:00

It is very difficult to describe, but once seen it is easy to understand. The author knows of nothing that it resembles so much as a helical spring crushed down sideways, as shown in Fig. 2, the torch tip following the path of the spring wire, advancing a little, as from coil to coil, at each revolution. The speed of rotation and advance have to be made to suit the work. Of course, in heavy welds this cannot be done, as metal is added. In this case, the wire should be used as a sort of a center around which the torch is oscillated, the path being somewhat more than a half circle. In this case, the wire should never be removed from the pool of melted steel, as the tendency is then to bum it. The flame should not be turned directly against the welding-wire, but kept far enough away from it so that while the wire is melted, the flame does not touch it; and the flame should not be kept on the metal any longer than is absolutely necessary.

■d^yCoogle

Steel does not form a comparatively large melted pool, as in the case of cast iron, and for this reason, and because of its rapid solidification, it is necessary to be careful about welding the edges of the pool. As soon as the metal is brought to the meltii^ point, if the torch is raised suddenly, the metal which has been blown into a shallow cup shape by the force of the blast will at once become level and solidify. Hence, a good steel welder keeps his torch constantly in motion, using the rotary movement and quick elevation.

Size of Torch Tip. — From what has been said of the dai^er of burning steel, it is evident that it is important to use the t^ht size of tip, neither too large nor too small, and also to provide sufficient sizes of wire to prevent the burning to which it is liable. The author finds that three sizes are sufficient for the majority of the work of an ordinary welding shop — ^, }, and -A inch.

Importance of Neutral Flame. — It is evident that, on account of the affinity of iron for oxygen at a high temperature, the flame should be neutral, and not only this, but there should be no oxygen escaping from the torch where it can combine with the melted metal. This is particularly important in the case of steel. The author knows of instances where it was impossible with a certain type of torch to produce satisfactory welds, while another, which used less oxygen, gave entirely satisfactory results. This emphasizes the importance of good apparatus.

Heat-treatment of Welded Steel. — It should be rem^n-bered that the weld is only a casting, and that it has received no forging or other treatment to refine the grain and to make the metal of better quality. In a few cases an extra amount of metal can be added to the

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.