Study On The Machinability Of Non-quenched And Tempered Steels And Tiβ21s

This dissertation is composed of two parts,That is, the study of the machinability of the new developed non-quenched and tempered steels and the Ti beta 21s.Non-quenched and tempered steels can be directly used in engineering without quenching and tempering, compared with common alloy steels. These steels have found a wide application in industry. So it becomes important to study their machinability. The work of this dissertation had be done under the commission of BaoShan Steel Company.In this paper, the machinability contrast tests on the 9 kinds of steel samples were made in turning, milling, polishing and EDM (electro-discharge machining). The machinability of these steels was objectively valued and the favorable steels were selected to being used in the second stage. In the second stage, the parameters optimization tests on the selected steels were made, and the optimized cutting parameters of turning and milling were presented. At last, the cutting mechanism of these steels were studied by the cutting force, cutting temperature and metallograph. Theoretical supports and improvement suggestions to the enterprise were provided through the work.Beta 21s titanium alloy was developed by TIMET company in America in recent years. It has many excellent properties, but its machinability is poor. By the test of the tool ware and the measure of the milling force, the evaluation of machinability and the optimized milling parameters were given out to help production.