Jianguo Zhao

The Study on Microstructure and Wear Resistance of In-situ Synthesis of TiAl(CN)/Fe Cermet Composite Coating

With Ti powder, Al powder and graphite powder as the coating material, and with industrial N2 as the shielding gas and reactive gas, the TiAl(CN)/Fe Cermet Composite Coating were prepared on the surface of Q235 steel base on Reactive Nitrogen Arc cladding by the TXII500 argon arc welding machine. The microstructure, phases and micro-hardness were investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and MH-6 micro-hardness instrument. The wear loss of TiAl(CN)/Fe coating and 65Mn steel were analyzed and compared by HSR-2M friction and wear testing machine under room temperature dry sliding wear. The experiments show that the coating and the substrate forms metallurgical bond without stomata andcrack; the coating are composed of TiAl(C0.51N0.12) phase, AlFe3 phase,FeC phase; the micro-hardness of TiAl(CN)/Fecoating is 1110HV0.5 high, about 4 times of base metal; comparing with the 65Mn,the wear weight loss of TiAl(CN)/Fe coating is about 1/2 times, the wear resistance of TiAl(CN)/Fe coating is excellent. KeywordsIn-Situ Synthesis; Reactive Nitrogen Arc Cladding; Tial(CN) Cermet; Microstructure; Wear Resistance

Design and Implementation of Welding with Electromagnetic Trailing Peening Control Circuit

In order to eliminate welding stress and improve the quality of welding.The technology of constant frequency pulse width modulation (PWM) is applied in the design of control circuit of welding with trailing peening.AT89C52 is the core of the circuit.This systemby the BCD dial provide reference voltage to the single-chip,by controlling the device of trailing peening to achieve the controlling of peening force. By changing the input voltage of V/F voltage frequency converter LM331 to achieve adjusting of peening frequency.The experiment has proved that circuit is reliable, and easy to achieve self-governed adjusting of peening force and peening frequency in welding.

TiN/Al 2 O 3 -reinforced composite coating prepared by reactive nitrogen-arc cladding process

A TiN/Al2O3-reinforced composite coating was fabricated on 45# steel substrate by reactive nitrogen-arc cladding process with Ti-Al2O3-Fe-Ni60A powder blends as cladding materials and pure nitrogen as reactive and protective gas. The microstructure, microhardness, and wear behavior of the composite coating were investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), microhardness tester, and the friction abrasion testing machine. The formation mechanism of the phases in the composite coating was discussed. Results show that the composite coating consists of primary TiN/Al2O3 as the reinforcing phase. The ceramic composite coating is metallurgically bonded to the 45# steel substrate. The ceramic composite coating has high hardness and excellent wear resistance.

Study on the Corrosion Resistance of TiCcoating Bytungsten Argon Arc Surfacing Welding

Corrosion is not just among the most important reasons for material loss and energy consumption, it also one of the main causes for the failure of mechanical parts [1-2].Using excellent surface strengthening technology and, performing anti-corrosion coating on metallic material surfaces can not only improve the reliability and service life of products, it can also reduce product repair and replacement. In addition, surface-strengthening technology can also save material and energy, which contributes to the protection of the environment and aligns with a sustainable development strategy. This paper utilizes tungsten argon arc surface welding technology to study the corrosion resistance of titanium carbide(TiC) coating. Graphite powder, titanium(TiC) powder, and iron(Fe) powder as pre-applied powders were put on 45 steel surfaces to prepare TiC/Fe matrix composite coating using in-situ synthesis technology. The microstructure and properties of the coating were investigated by measuring the open circuit potential, polarization curve in 3.5% sodium chloride (NaCl) solution, 5% sulfuric acid (H2O4)solution. The conclusions were verified using weight loss method. The results of the experiment show that in 3.5% sodium chloride solution, the stable corrosion potential of TiC coating is higher than 45 steel. Other effects include a decrease in the thermodynamic trend of corrosion reaction and a reduction in the possibility of corrosion. However it did not change obviously in 5% sulfuric acid solution. Thus the corrosion rate of TiC coating is higher than 45 steel in 3.5% sodium chloride solution and 5% sulfuric acid solution. KeywordsTungsten ArgonArc Surfacing Welding; Composite Coating; TiC; Corrosion Resistance