Effect of Ti Content on the Behavior of Primary Carbides in H13 Ingots

Abstract

The Ti element plays a role in pinning grain boundaries but also has a good binding ability to C and N, forming large primary carbides. Therefore, the effect of Ti content on primary carbides’ behavior in H13 ingots was comprehensively studied. A non-aqueous electrolysis method was used to determine the three-dimensional (3D) characteristics of primary carbides. We found a great difference between the two-dimensional (2D) and the three-dimensional characteristics of primary carbides. When performing 2D analyses, the density of the primary carbides appeared high, while their size was small. The actual characteristics of primary carbides can be obtained only by 3D observation. The primary carbide showed a typical dendritic structure, whose center consisted of Ti–V-rich carbide wrapped by V-rich carbide. As the Ti content increased, the size of the primary carbide increased from 24.9 μm to 41.3 μm, and the number density increases from 25.6 per/mm2 to 43.9 per/mm2. The Ti4C2S2 phase precipitated first, then changed into Ti–V-rich carbide, and finally further partly transformed into V-rich carbide. The addition of elemental Ti promoted the precipitation and transformation of primary carbides, resulting in an increase of the number density and size.

Effects of Ti and N Contents on the Characteristic Evolution and Thermal Stability of MC Carbonitrides Holding at 1250 °C in H13 Die Steel

“…Extensive research has been conducted, showing that alloying elements such as Ti [2], Nb [3], and Mg [4], and rare-earth metals [5][6][7], could affect the precipitation and characteristics of carbonitrides in H13, in addition to the cooling rate and axial static magnetic field during the solidification process [8,9]. There are mainly two kinds of MC precipitates in H13, including V-rich and Ti-containing carbonitrides [2,10,11]. The precipitation temperature of Ti-containing MC precipitates can be significantly enhanced by increasing the concentration of Ti in H13.…”

“…The precipitation temperature of Ti-containing MC precipitates can be significantly enhanced by increasing the concentration of Ti in H13. Those precipitates can also act as the heterogeneous core of V-rich MC carbonitrides and influence the characteristics of MC carbonitrides in commercial H13 [2,10]. The quantities and sizes of precipitates increase as the Ti content increases from 0.011 wt% to 0.036 wt% in lab-scale H13 steel [10].…”

“…As a main type of primary carbonitrides in H13 steel, the large Ti-containing MC carbonitride with sharp corners and high hardness is much more stable than the V-rich MC carbonitride at a high temperature [5,21,22]. The MC primary carbonitrides are considered to be controlled by Ti contents [2,10,11] and the cooling process during solidification [9]. Nevertheless, prohibiting the precipitation of carbonitrides may be quite difficult concerning the industrial practices involving H13 steel.…”

“…Recently, researchers have been interested in the influences of different Ti contents on the characteristics of carbonitrides in H13 [2,10,11]. Some studies have been carried out on the evolution of MC precipitates [14,15,19] in H13 at high temperature.…”

Enhancement of Wear Resistance on H13 Tool and Die Steels by Trace Nanoparticles

“…Tool and die steels should not only ensure wear resistance, but also need good impact toughness, which can guarantee that they have a long service life under wear conditions [1][2][3][4][5]. For example, the shield machine rolling tools generally made of tool and die steels with high Cr content [6][7][8][9][10][11] have good mechanical properties represented by impact toughness, as well as high wear resistance [12][13][14]. The main reason is that when the rolling tool is used for rock rolling, it bears the abrasive wear condition under high stress, and a large amount of heat is generated by instantaneous friction, which makes the tool surface temperature rise rapidly [15][16][17].…”