Low-field magnetic analysis for sigma phase embrittlement monitoring in thermally aged 22Cr duplex stainless steel

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:513

Article

Silva, David D. S.¹  Raimundo, Rafael A.^1,2  Torquato, Ramon A.³  Faria, Geraldo L.⁴  Morales, Marco A.²  Simoes, Thiago A.^3,5  Gomes, Rodinei M.¹ 

[1] Univ Fed Paraiba, Mech Engn Postgrad Program, BR-58051900 Joao Pessoa, Paraiba, Brazil

[2] Univ Fed Rio Grande do Norte, Dept Theoret & Expt Phys, BR-59078970 Natal, RN, Brazil

[3] Univ Fed Paraiba, Mat Sci & Engn Postgrad Program, BR-58051900 Joao Pessoa, Paraiba, Brazil

[4] Univ Fed Ouro Preto, Dept Mat & Met Engn, BR-35400000 Ouro Preto, MG, Brazil

[5] UFRB, Ctr Sci & Technol Energy & Sustainabil, BR-44042280 Feira De Santana, BA, Brazil

关键词: Duplex stainless steel (DSS);    Sigma phase;    Low-field magnetic analysis (LFMA);    Nondestructive testing (NDT);   

DOI  :  10.1016/j.jmmm.2020.167072

来源: Elsevier

【 摘 要 】

The aim of this study is to evaluate a new nondestructive method designated as Low-Field Magnetic Analysis (LFMA) based on the measurement of magnetic flux density for monitoring sigma (sigma) phase precipitation in duplex stainless steel (DSS). In addition, the effect of isothermal aging treatment at 800 degrees C on the metallurgical degradation of UNS 531803 DSS was investigated. It was found a change in the volume fraction of alpha-Fe/gamma-Fe phases due to alpha-Fe (ferromagnetic phase) eutectoid decomposition to precipitate sigma and secondary austenite (paramagnetic phases). A significant and gradual reduction of saturation magnetization was observed with the increase of thermal treatment time, indicating a decrease in the quantity of alpha-Fe phase. Two magnetic methods were used to verify the evolution of the a phase: M - H measurements at 300 K using a commercial magnetometer and LFMA testing. Both methods were sensitive to small percentages of a phase in the microstructure. Furthermore, our developed technique presents accurate results for low magnetic fields with high sensitivity and reliability.

【 授权许可】

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