Influence of Scanning Speed on Plasma Beam Remeltsolidified Layers Microstructure and Performance of Nodular Cast Iron
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Key Words：Nodular cast Iron； Plasma beam； Remeltsolidified hardening； Wearability
Abstract：Microstructure and performance of plasma beam remeltsolidified layer of nodular cast iron surface under different scanning speeds have been analyzed. The results show that micromeltedsolidified hardening of the nodular cast iron surface can be obtained when the working current is 60 A and the welding voltage is 30 V, whereas the scanning speed increases from 10 mm/s to 50 mm/s. Along with the scanning speed increasing, the width and depth of remeltsolidified layer and hardened layer diminishes, and maximum hardness increases. In remeltsolidified region graphite vanished and the microstructure at room temperature is tiny modi fied ledeburite and remaining austenite. In transformation hardening region is acicular martensite, modified ledeburite and dou
ble shell structure consists of modified ledeburite and martensite, in the center of shell is nodular graphite. The microhardness of double shell structure is up to 917.8 HV0.1, Which is advantageous to enhance wear resistance.
