Product Code: ICA13_1602

Microstructure and Corrosion Resistance of Laser Alloying Coating In-Situ Synthesized on Ductile Iron
Authors:
Qiwen Wu, Tsinghua Uniersity; Beijing Peoples Republic of China
Mingxing Ma, Tsinghua University; Beijing Peoples Republic of China
Weiming Zhang, Tsinghua University; Beijing
Wenjin Liu, Tsinghua University; Beijing
Cunyuan Peng, Tsinghua University; Beijing
Presented at ICALEO 2013

As a ferrite ductile iron, QT450-10 is often used in the valve manufacturing industry, due to its good corrosion resistance. Laser produced composite coatings reinforced by in-situ particles have been proved to have a lot of benefits for industrial application, owing to their high wear resistance, corrosion resistance, high temperature characteristics, etc. Thus, fabricate particle reinforced coatings on ductile iron by laser alloying could be a good way to increase the valve’s service life, and would be a promising application in the manufacturing industry.

In the present study, large-area composite coatings reinforced by in-situ particles with high nickel content were produced on QT450-10 by laser alloying, using the alloying powder with C-Si-B system developed by Tsinghua Laser Processing Research Center. The results reveal that the coatings have high cracking tendency, due to the high carbon content of the molten pool produced by laser beam. Vary the content of graphite and rare earth oxide in the alloying powders, and investigate the effect on the coatings’ cracking tendency. Meanwhile, change the laser processing method by conducting laser-melting treatment on the substrate firstly, aiming to melting the spheroidal graphite prior to the laser alloying treatment. Thus, reduce the crack density of the alloying coatings. Besides, the influence of different alloying powder composition and laser processing method on the coatings’ microstructure, microhardness and corrosion resistance, which is revealed by electrochemistry experiments, is also investigated.