Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/tmm.2012.026
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

ANÁLISE NUMÉRICA E EXPERIMENTAL DAS TENSÕES RESIDUAIS GERADAS NA TÊMPERA DE UM CILINDRO DE AÇO AISI 4140

NUMERICAL AND EXPERIMENTAL ANALYSIS OF RESIDUAL STRESSES GENERATED DURING HARDENING OFAISI 4140 BAR

Echeverri, Edwan Anderson A.; Tschiptschin, André Paulo

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Resumo

O objetivo deste trabalho é analisar a distribuição das tensões residuais que resultam da combinação das variações volumétricas resultantes dos gradientes térmicos e das transformações de fase que ocorrem durante a têmpera de um cilindro de aço AISI/SAE 4140. O modelo matemático usado para este objetivo utiliza o software AC3 de modelagem de tratamentos térmicos (curvas de transformação, curvas de resfriamento e a microestrutura do material), para alimentar um modelo de elementos finitos, considerando acoplamento termomecânico e comportamento não linear elasto-plástico, para previsão de tensões residuais em cilindros de aço 4140 temperados. São apresentados, também, os resultados de observações metalográficas que confirmam, quantitativa e qualitativamente, as previsões do software AC3. A verificação do modelo numérico é efetuada por meio da medida das tensões residuais pela técnica de difração de raios X. A simulação numérica, por elementos finitos, evidencia a existência de tensões residuais de compressão, da ordem de 350 MPa, na região superficial após têmpera e indica de que as tensões mais significativas são as tangenciais.

Palavras-chave

Modelagem, Método de elementos finitos, Têmpera, Tensão residual

Abstract

The aim of this work is to analyze the distribution of residual stresses resulting from the combination of volumetric changes due to heat gradients and phase changes occurring during the quenching process of an AISI/SAE 4140 steel cylinder. The mathematical model used for this objective is the AC3 modeling software of thermal treatments (transformation curves, cooling curves and microstructure), whose results were input in an finite element model, considering thermal-mechanical coupling and non-linear elastic-plastic behavior, aiming the assessment of residual stresses in quenched 4140 steel cylinders. The observed microstructure confirms quantitatively and qualitatively the previsions of the AC3 Software. The results of the modeling are compared with the residual stresses measurements made using X-Ray diffraction techniques. The finite element numerical simulation shows the existence of 350 MPa compressive residual stresses in the surface region and indicates that the most significant stresses are tangential.

Keywords

Modeling, Finite element method, Quenching, Residual stress

Referências

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