Test Method for Cold Bonding Strength of Refractory Mortar

Three kinds of surfacing layers of the austenitic steel, niobium alloyed steel and hypereutectic high chromium alloyed cast iron were prepared on 1045 steel substrate by arc surfacing process with self-shielding flux-cored wires. The bonding strength between surfacing layers and the substrate was tested by pull-lift test method. The experimental results show that the bonding strength between austenitic steel surfacing layer and the substrate is the highest up to 549.1 MPa, and the fracture location is near the fusion line with quasi-cleavage fracture characteristic. The bonding strength between the surfacing layer of niobium alloyed steel and the substrate is 314.4 MPa and the fracture mainly occurred at the bottom of the surfacing layer, which also presents quasi-cleavage characteristic. While the bonding strength between hypereutectic high chromium alloyed cast iron surfacing layer and the substrate is as low as 170.7 MPa and the specimen ruptures along the fusion line with brittle fracture characteristic. The bonding properties between surfacing layers and the substrate are directly related to the compositions and microstructures near the fusion line.

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Effect on Reverse Transferred Arc Treating on Bonding Strength in Low Pressure Plasma Spraying

Thermal Spray 1996: Proceedings from the National Thermal Spray Conference ◽

10.31399/asm.cp.itsc1996p0405 ◽

1996 ◽

Author(s):

K. Honda ◽

I. Chida ◽

T. Fuse ◽

T. Murakami ◽

K.F. Kobayashi

Keyword(s):

Plasma Spraying ◽

Bonding Strength ◽

Low Pressure ◽

Test Method ◽

Pressure Plasma ◽

Low Pressure Plasma ◽

Transferred Arc ◽

Sprayed Coating ◽

Plasma Sprayed ◽

Low Pressure Plasma Spraying

Abstract Both bonding strength of coating to substrate in low pressure plasma spraying and the effect of reverse transferred arc treating before spraying are studied in this paper. It is difficult to obtain the bonding strength precisely in low pressure plasma spraying by standard testing methods, such as, ASTM Standard C633-79 and JIS H8666-80. Therefore, for the bonding strength test rather than using a conventional adhesive, we believe a vacuum brazing process using Ag-Cu-In-Ti active filler metal at 1023 K should be used. We have also confirmed the practicality of this step. By the above test method, it has been proven that the bonding strength of low pressure plasma sprayed coating is over 100 MPa. Also, that reverse transferred arc treating after blasting enhances the bonding strength of low pressure plasma sprayed coating. It is also believed that the projections formed on the substrate surface by reverse transferred arc treating are buried into the coating and perform the pile effect.

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