H. Doostmohammadi - Assistant Professor of Department of Materials Engineering and Metallurgy, Faculty of Engineering, Shahid Bahonar University, Kerman, Iran
H Esmaeilipour - Shahid Bahonar Copper Industries Co, Kerman, Iran

The admiralty brass tubes (ABTs) usually contain copper, zinc and small amounts of tin. These tubes usually inhibit dezincification in corrosive environments. Application of the ABTs in different industries highly depends on the quality of these tubes. More specifically, presence of even very small cracks along the tube highly reduces the demand for these tubes in industries. Therefore, process control of the production of the ABTs is of great importance. The most applied method for production of the ABTs is hot extrusion. One of the major factors affecting creation of cracks is extrusion rate. In this study, creation of cracks along the admiralty brass tubes using several extrusion rates was investigated. It was found that increment of extrusion rate correlates directly with crack creation. Also, the inhomogenity of grain size between the inner and outer surfaces of the tube was observed to be more in cracked tubes. Furthermore, the optimum rate of extrusion for a group of ABTs (80×10×9000 mm) with respect to zero crack level was determined.

Admiralty brass tube, crack, extrusion rate, grain size