Two-Phase Master Sintering Curve for 17-4 PH Stainless Steel
- PDF / 2,148,427 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 68 Downloads / 196 Views
INTRODUCTION
THE grade 17-4 PH stainless steel is a precipitation hardening martensite stainless steel with high strength and good corrosion resistance. Due to these advantages, 17-4 PH stainless steel has been widely used in medical, automotive, aircraft, and military applications. Exceptionally high tensile strength with moderate ductility is obtained by the combination of solid solution hardening, precipitation strengthening, and phase transformation from austenite to martensite during heat treatment. This alloy, however, has low machinability, and the conventional processing methods are only limited to simple shape components. Therefore, particulate material (PM) manufacturing methods have been actively studied and applied to this alloy. For example, powder injection molding, a near-net shape manufacturing technology, is known to easily fabricate 17-4 PH stainless steel to full density.[1–6] Sintering is a thermally activated process used to manufacture PM. Densification via sintering is associated with a volume change (shrinkage) governed by the conservation of mass. It is critical to the PM manufacturer to monitor and control the concomitant IM DOO JUNG, Postdoctoral Researcher, and SEONG JIN PARK, Professor, are with the Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyojadong, Nam-gu, Pohang 790-784, Republic of Korea. Contact e-mail: [email protected] SANGYUL HA, Principal Research Engineer, is with Samsung Electro-Mechanics, Mayoung-Ro 150, Suwon, Republic of Korea. DEBORAH C. BLAINE, Professor, is with the Department of Mechanical and Mechatronics Engineering, Stellenbosch University, Matieland 7602, South Africa. RAVI BOLLINA, Professor, is with the School of Engineering Sciences, Mahindra Ecole Centrale, Hyderabad, Telangana, India. RANDALL M. GERMAN, Professor, is with the Mechanical Engineering Department, San Diego State University, San Diego, CA 92182. Manuscript submitted June 10, 2015. METALLURGICAL AND MATERIALS TRANSACTIONS A
densification and shrinkage to produce quality materials within specified density and dimensional limits. To this end, various sintering models have been proposed over the past decades.[7–27] One of the simplest and most functional models is the master sintering curve (MSC), originally developed by Su and Johnson.[28] The MSC approach has served as the foundation for a number of studies aimed at modeling the sintering process for various PM material systems.[29–43] The MSC approach is used to predict sintering densification by considering one sintering mechanism to be dominant and persistent over the entire sintering cycle. For many of the PM systems that have been studied, this is an appropriate assumption.[36,37,41–43] However, 17-4 PH stainless steel exhibits different sintering behaviors at different temperatures, dependent on the phases that appear during sintering.[24,44–46] These phase changes have been confirmed by a study of the microstructural evolution during sintering of powder injection-molded 17-4 PH stainless steel.[47
Data Loading...
