Impact of Forging Conditions on Plasma Nitrided Hot-forging Dies and Punches

Abstract

<p>In this work an effort has been made to study the effect on the performance of the plasma nitrided AISI H13 hot-forging dies and punches in two different forging service conditions –namely, fully-automatic and semi-automatic processes. The plasma nitriding is performed to increase the surface properties like –wear resistance and surface hardness of these components. After plasma nitriding the surface hardness of these materials has increased typically from ~500 HV_0.01to ~1200 HV_0.01. In the plasma nitriding process high-voltage electrical energy is used to form plasma through which nitrogen ions are accelerated to impinge on the workpiece. The ion bombardment heats the workpiece, cleans the surface, and provides active nitrogen to make iron-nitride compounds. The iron-nitride compounds then diffuse to the workspace to harden the surface. In these two service conditions the plasma nitrided hot-forging dies and punches have shown typically 2.5 to 4 times increment during the performance. It is observed that the increment in the performance of the dies and punches depends on the forging service conditions, i.e., temperature of the dies and punches, shot repetition time and effective cooling of dies and punches in service conditions. Four times increment in the performance of dies and punches is found in the semi-automatic process, whereas two and half times increment in performance of dies and punches is observed in the fully-automatic process.</p

Failure analysis of forging die insert protected with diffusion layer and PVD coating

“…Changes in dimensions of hot forging dies due to wear or plastic deformation, deterioration of the surface finish, breakdown of lubrication, and cracking of surface layer, were all previously investigated by many researchers [5][6][7][8][9][10]. It was established that the thermal softening effect is the most common cause for die surface hardness decrease, which accelerates the die failure [11].…”

High-temperature tribological studies of plasma-nitrided tool steels

“…Dimensional stability at elevated temperatures is also equally required. The properties of these components should be improved [7][8][9].…”

Effects of Annealing Temperature on Raman Scattering and Electrical Properties of Te-Doped Nanostructured Black Silicon

“…Due to high absorptance (>90%) (Crouch et al, 2004) and wide absorption spectrum ranging from ultraviolet (UV) to near infrared (NIR) (Younkin et al, 2003;Das et al, 2012;Sheehy et al, 2005), nanostructured black silicon is an ideal material to fabricate sensitive photodetectors, solar cell (Yuan et al, 2009;Koynov et al, 2006), biochemical sensor (Noval et al, 2011), display devices (Treado et al, 1994;Tezcan et al, 2003;Fixe et al, 2004), gas sensor (Trakhtenberg et al, 2012). Nanostructure of the black silicon has been the focus of intense interest in recent years due to their extensive device application (Li et al, 2011;Li et al, 2008;Kumar et al, 2012). There are mainly four ways to fabricate black silicon-femtosecond laser (Wu et al, 2001;Kabashin et al, 2010;Othonos et al, 2009), deep reactive ion etch (DRIE) (Fischer et al, 2009), metal assisted wet etching (Branz et al, 2009), and electrochemical etching (Ma et al, 2006).…”