You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    Volume 7, Issue 1 (November 2018)

    Optimization of Hot Workability and Control of Microstructure in 18Ni (M250 Grade) Maraging Steel Using Processing Maps

    (Received 27 May 2018; accepted 4 October 2018)

    Published Online: 27 November 2018

    CODEN: MPCACD

      Format Pages Price  
    PDF (2.49 MB) 15 $25   ADD TO CART

    Cite this document

    X Add email address send
    X
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word



    Abstract

    This article examines the hot working characteristics of M250 grade maraging steel by performing isothermal compression tests varying the temperatures and strain rates. A processing map has been developed, indicating microstructurally “stable” and “unstable” regions during hot working. At strain rates (ϵ, ˙, , , , , ) above 0.1 s−1 and temperatures (T) below 1,000°C, stress–strain curves show strain hardening behavior, whereas steady-state behavior is shown at strain rates below 0.01 s−1 and temperatures above 1,050°C. Above 1,150°C, flow softening is observed at 0.001 and 0.01 s−1. In the processing map, two distinct microstructurally stable domains are observed: one is at T = 1,150–1,200°C and ϵ, ˙, , , , ,  = 0.001–0.01 s−1, and another is at T = 1,000–1,150°C and ϵ, ˙, , , , ,  = 0.001–0.1 s−1. Based on microstructural observations, electron backscattered diffraction results, and the high efficiency of power dissipation, dynamic recrystallization is the softening mechanism. A constitutive relation useful in computer modeling is developed, using the generated flow stress data.

    Author Information:

    Chakravarthi, K. V. A.
    Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Trivandrum,

    Department of Mechanical Engineering, Koneru Lakshmaiah Education Foundation, K L Deemed to be University, Green Fields, Vaddeswaram, Guntur

    Koundinya, N. T. B. N.
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Madras, Chennai,

    Sarkar, Aditya
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai

    Narayana Murty, S. V. S.
    Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Trivandrum,

    Nageswara Rao, B.
    Department of Mechanical Engineering, Koneru Lakshmaiah Education Foundation, K L Deemed to be University, Green Fields, Vaddeswaram, Guntur


    Stock #: MPC20180082

    ISSN:2379-1365

    DOI: 10.1520/MPC20180082

    Author
    Title Optimization of Hot Workability and Control of Microstructure in 18Ni (M250 Grade) Maraging Steel Using Processing Maps
    Symposium ,
    Committee A01