Article Periodicals » Materials Evaluation » Article
Discontinuity Characterization in Standard Nodular Iron using Nondestructive Techniques

Nodular irons have been used with increasing frequency because of their relevant mechanical properties compared to its cost. However, they have defects sometimes associated with solidification, which decreases their mechanical properties. This study analyzed the types of defects in a new nodular iron alloy 100-70-03, which are typically used in the automotive industry. The techniques used in the analysis were microstructural characterization and nondestructive tests such as ultrasound, penetrating liquids, and hardness tests. The results of the microstructural characterization identified nodular iron with a pearlitic matrix. The nondestructive testing revealed defects consisting of voids, microshrinkage, porosity, and microporosity. The dye tests showed porosity on the surfaces, while hardness testing revealed that the material is within the specification. At the end of the characterization, it was found that the new alloy has the proper microstructure and hardness.

References
  • AFS, “Casting Quality Test Methods,” About AFS and Metalcasting, American Foundry Society, last revision 7 July 2015, www.afsinc.org/about/content.cfm?itemnumber=6955.
  • AMIA, Figures for January 2015, Mexican Association of Automotive Industry, Mexico City, Mexico, January 2015.
  • ASM, ASM Handbook Vol. 1: Properties and Selections: Irons, Steels, and High-performance Alloys, 10th ed., ASM International, Materials Park, Ohio, 1990.
  • ASTM, ASTM A 536-84, Standard Specification for Ductile Iron Castings, ASTM International, West Conshohocken, Pennsylvania, 2009.
  • ASTM, ASTM E 10-12, Standard Test Method for Brinell Hardness of Metallic Materials, ASTM International, West Conshohocken, Pennsylvania, 2012a.
  • ASTM, ASTM E 164-13, Standard Practice for Contact Ultrasonic Testing of Weldments, ASTM International, West Conshohocken, Pennsylvania, 2013.
  • ASTM, ASTM E 165/E 165M-12, Standard Practice for Liquid Penetrant Examination for General Industry, ASTM International, West Conshohocken, Pennsylvania, 2012b.
  • ASTM, ASTM E 3-11, Standard Guide for Preparation of Metallographic Specimens, ASTM International, West Conshohocken, Pennsylvania, 2011.
  • ASTM, ASTM E 446-14, Standard Reference Radiographs for Steel Castings Up to 2 in. (51 mm) in Thickness, ASTM International, West Conshohocken, Pennsylvania, 2014.
  • ASTM, ASTM E 8/E 8M-15a, Standard Test Methods for Tension Testing of Metallic Materials, ASTM International, West Conshohocken, Pennsylvania, 2015.
  • Avner, S.H., Introduction to Physical Metallurgy, second edition, Spanish translation, McGraw-Hill, Mexico City, Mexico, 1991, pp. 420–426.
  • Carazo, F.D., S.M. Giusti, A.D. Boccardo, and L.A. Godoy, “Effective Properties of Nodular Cast-iron: A Multi-scale Computational Approach,” Computational Materials Science, Vol. 82, No. 1, 2014, pp. 378–390.
  • Cho, G.S., K.H. Choe, K.W. Lee, and A. Ikenaga, “Effects of Alloying Elements on the Microstructures and Mechanical Properties of Heavy Section Ductile Cast Iron,” Journal of Materials Science & Technology, Vol. 23, No. 1, 2007, pp. 97–101.
  • Dwivedi, S.N., and A. Sharan, “Development of Knowledgebased Engineering Module for Diagnosis of Defects in Casting and Interpretation of Defects by Nondestructive Testing,” Journal of Materials Processing Technology, Vol. 141, No. 2, 2003 pp. 155–162.
  • Ecob, C.M., “A Review of Common Metallurgical Defects in Ductile Cast Iron,” Elkem Foundry Products, 2010.
  • Lapoint Morales, R., “Evaluación Cualitativa y Cuantitativa de los Defectos mas Comunes en las Fundiciones Grises y Nodulares,” graduate thesis, Universidad Simon Bolivar, Sartenejas, Venezuela, 2010, p. 149.
  • Li, X., X. Li, W. Liang, and L. Chen, “ℓ0-norm Regularized Minimum Entropy Deconvolution for Ultrasonic NDT & E,” NDT&E International, Vol. 47, 2012, pp. 80–87.
  • Olea, O.M., “Estudio del Efecto de la Densidad de Nódulos Sobre las Propiedades Mecanicas del Hierro Dúctil,” graduate thesis, Instituto Politecnico Nacional, Mexico City, Mexico, 2010, p. 106.
  • Rizzo, N., “Defectos Espontáneos de Solidificaciónen Hierro Nodular Hipereutéctico,” Fifth Latin American Congress on Casting, Buenos Aires, Argentina, 15–17 November 2012, pp. 1–17.
  • Sillén, R., “Finding the True Eutectic Point—An Essential Task for Efficient Process,” Keith Millis Symposium on Ductile Cast Iron, American Foundry Society/Ductile Iron Society, Strongsville, Ohio, 2008, pp. 100–103.
Metrics
Usage Shares
Total Views
177 Page Views
Total Shares
0 Tweets
177
0 PDF Downloads
0
0 Facebook Shares
Total Usage
177