Abstract:

When the copper-rotating band of bullet is clad by means of tungsten inert gas (TIG) welding, the infiltrated cracks are usually appeared. The pure iron (carbon content of less than 0.04%) was selected to produce rotating band as the cladding materials instead of copper. The cold-wire TIG welding, newly designed hot-wire TIG welding and vibration TIG welding were adopted to clad the pure iron to the 20# steel surface of bullet. The cladding speed of coldwire welding was 1.3m/min, while the hotwire welding was 1.8m/min, which is faster than cold-wire welding. The cladding speed of vibration welding was 1.6m/min. Besides, it can reduce the welding current by 10A. The interface and cladding layer of welding joints produced by different welding methods were analyzed. The hot-wire welding made the grains connecting the interface and the cladding layer grow up, while the vibration TIG welding made them more smaller. The vibration welding can reduce the average hardness of cladding layer to HV160, or by HV15 or so compared with the other two methods. Shearing experiments show that the value of intensity on the connecting interface is much higher than its original intensity of bullet's cladding layer. From the results of shooting experiments, it can be seen that pure iron is another kind of feasible alternatives for copper as the cladding material.

Key words: ordnance science and technology, pure iron, bullet's rotating band, hot'wire TIG welding, vibration TIG welding