Estudo comparativo do desgaste de rolos de lingotamento contínuo SAE 4140 revestidos de aço inoxidável AISI 411

Abstract

The present research intends to investigate, by means of analysis of properties, the physical integrity of SAE 4140 industrial rolls coated by AISI 411 stainless steel, belonging to a twin continuous casting machine, considering the relation between wearness and loss of characteristics, essential parameter to preserve the service life of the machine components. 4 (four) samples, each one submitted by rework process, 3 (three) of them were been processed by company A, and 1 (one) by company B, that, after identified, were been analyzed considering mechanical properties, as well as chemical properties and physical metallurgy. Although the possibility to observe mechanical flaws in naked eye, it is stated to have the appearance of intergranular microcrackspropagating along the grainboundaries of the coating on the microstructure. Besides, it is deduced that, along the continuous solidification, there has been noticed thermal phenomena arising from the temperature on the rolls surface, perpetuatingby conduction along the material, indirectly causing a heat treatment called normalization on substract and,on the interface, thesubstract-coating. In conclusion, summarily, disconsidering further parameters of the machine (applied tension, solidification rate, etc),the rolls had been submitted to higher temperatures than stipulatedfor enough time to generate a succession of flaws, reducing, thus, the rolls service life.