Effects of TiCN Composite Die with Low Thermal Conductivity on Hot Forging Performances

Abstract

Titanium carbonitride based composite (TiCN-metallic binder) was developed as die material for replacement of cemented tungsten carbide. The effects of thermal conductivity characteristic of the TiCN composite on hot forging performances were investigated using a servo press with ram motion control. Three types of the die materials; (a) tool steel for hot working, (b) cemented tungsten carbide with high thermal conductivity and (c) TiCN composite with low thermal conductivity were compared. In hot upsetting of a chrome steel workpiece, the TiCN composite die was confirmed to reduce the forging load by approximately 20% at slow forging speed. This is because the die with low thermal conductivity could prevent the workpiece from rapid cooling induced by heat transfer at the die-workpiece interface. In addition, the material flow of the workpiece to a die cavity was improved. Furthermore, the wear depth/wear coefficient of the TiCN composite was lower than that of the tool steel and the cemented tungsten carbide in the numerical analysis of wear due to the combination of low thermal conductivity and high hardness.

Lubrication in Hot Forging with Pulsed Ram Motion

“…The shear friction factor along the hollow part of the upper die was varied in the range 0.1 ≤ m b1 ≤ 1.0, while the shear friction factors at the other parts of the upper and lower dies were assumed to be m b2 = m f = 0.4. The heat transfer coefficients for the die-workpiece interface and the free surface of the workpiece were determined from heating and cooling tests to be 6000 W•m -2 •K -1 and 100 W•m -2 •K -1 , respectively [13].…”

Strategic Selection of Refractory High-Entropy Alloy Coatings for Hot-Forging Dies by Applying Decision Science

“…Accordingly, conventional die steels, for example, H13, Finkl, 4340, and Uddeholm Dievar; specialty steels, including maraging steels; and superalloys like A286, 718, 720, Waspaloy, Hastelloy, and Stellite are common, depending on the application and the stringent requirements of the forging parts [3][4][5][6][7]. The performance requirements of hot-forging dies typically include good (a) hardenability, (b) toughness and ductility, (c) temper resistance, (d) hardness and strength at room and elevated temperatures, (e) wear resistance, (f) oxidation and corrosion resistance, (g) thermal conductivity, (h) thermal and mechanical fatigue, and some other requirements [3][4][5][6][7][8][9].…”