Título

INFLUENCE OF PHYSICAL AND CHEMICAL INTERACTIONS BETWEEN STEEL AND THEIR PRETREATMENT AND MACHINING CONDITIONS IN THE FORMATION OF SOFT SPOTS IN THERMOCHEMICAL TREATMENTS

INFLUENCE OF PHYSICAL AND CHEMICAL INTERACTIONS BETWEEN STEEL AND THEIR PRETREATMENT AND MACHINING CONDITIONS IN THE FORMATION OF SOFT SPOTS IN THERMOCHEMICAL TREATMENTS

Autoria

Zambon, Antonio Carlos; Oliveira, Flávio Bonafé; Bidá, André Gonçalves

Zambon, Antonio Carlos

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Oliveira, Flávio Bonafé

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Bidá, André Gonçalves

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DOI

10.5151/2594-5327-23466

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Resumo

Soft spots or reduction of the hardened layer in localized areas on parts thermochemical treated (Carburizing, Carbonitriding and Nitriding) are relatively common and are typically derived from one inadequate cleaning before treatment. Improper cleaning allows the presence of surface contaminants from cutting fluids used in the machining processes, acting as a barrier to the penetration of Carbon and Nitrogen in the heat treatment processes. This paper presents the problem of formation of soft spots during thermochemical treatments of steel in a more complex way than normal, from the interaction of several parameters which contribute to the formation of a passivation barrier, reducing the penetration of C and N during treatment. These parameters were associated with the type of steel and its pretreatment before machining, and various parameters of machining operations as those fluids, tools, and cutting speed. Solutions to avoid this kind of problem are also presented.

Soft spots or reduction of the hardened layer in localized areas on parts thermochemical treated (Carburizing, Carbonitriding and Nitriding) are relatively common and are typically derived from one inadequate cleaning before treatment. Improper cleaning allows the presence of surface contaminants from cutting fluids used in the machining processes, acting as a barrier to the penetration of Carbon and Nitrogen in the heat treatment processes. This paper presents the problem of formation of soft spots during thermochemical treatments of steel in a more complex way than normal, from the interaction of several parameters which contribute to the formation of a passivation barrier, reducing the penetration of C and N during treatment. These parameters were associated with the type of steel and its pretreatment before machining, and various parameters of machining operations as those fluids, tools, and cutting speed. Solutions to avoid this kind of problem are also presented.

Palavras-chave

Soft spots; Thermochemical treatments; Passivation barrier.

Soft spots; Thermochemical treatments; Passivation barrier.