ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Enhancing the surface characteristics of Nitronic-50 through pack boronizing

Ramakrishnan Hariharan, R. Balasundaram, K. Lenin, and D. Jafrey Daniel James

Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Tiruchirappalli, India

E-mail: ramakrishnanhmech@krce.ac.in

Received: 3 July 2024  Accepted: 8 April 2025

Abstract:

This investigation proposes to enhance the surface characteristics of a distinct grade austenitic stainless steel material named Nitronic-50 (UNSS20910). The primary applications of Nitronic-50 are in manufacturing valve components. The specimens of 10 mm diameter with 30 mm length were boronized by powder pack method in an electric furnace using 325-mesh boronizing medium. The input process parameters used are time, gas pressure, and temperature, and the output process parameters are hardness, specific wear rate, boronizing thickness. The total experimental runs for three levels with three process parameters are 27 (3 × 3x3). To reduce the 27 experimental runs to 9 runs, the analysis of variance (ANOVA) design is proposed. Optical microscope, Vickers microhardness tester, and wear tester were used to examine the prepared specimens. The surface morphology and creation of an iron carbide layer on the surface can be evidenced and measured by the SEM and optical microscope. Among the experiments, the sample with 975 °C and 4-h process shows better surface characteristics. For the same, the maximum boronizing thickness (65.688 µm), maximum surface hardness (1874.7 HV), and lower specific wear rate (0.000843 m³/Nm) were observed. The model inferred from ANOVA is significant, and the most influencing parameter for all the responses is time, followed with temperature. Thus, it is evidenced that the boronized UNSS20910 has very high surface hardness and wear resistance which reduces the service failures of the industrial components.

Keywords: Boron Nitride; Materials Characterization Technique; Surface Chemistry; Surface Spectroscopy; Tribology; Materials Engineering; Nitronic-50; Scanning electron microscope; X-ray diffraction; Boronizing; Wear

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04057-w

Chemical Papers 79 (7) 4303–4316 (2025)