Precipitation Behavior of Carbides in H13 Hot Work Die Steel and Its Strengthening during Tempering

Ning, Angang; Mao, Wenwen; Chen, Xichun; Guo, Hanjie; Guo, Jing

doi:10.3390/met7030070

Cited by 74 publications

(43 citation statements)

References 11 publications

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“…The single phase can be divided into two types, one is rich in Ti and V and the other is rich in only V. The one, rich in Ti and V, is more dominant in inclusions in 3# H13 steel. The gray and white dots in Figure are secondary carbides reprecipitated during the annealing process of forging materials . As the Ce content reached 0.03 wt%, the oxides in 3# H13 steel were transferred into Ce–O and Ce–O–S, as shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

Effect of Cerium on the Behavior of Inclusions in H13 Steel

Huang

Cheng

et al. 2018

steel research int.

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The modification mechanism of cerium (Ce) on oxides and multilayer carbontrides in H13 steel is investigated by industrial trials and thermodynamic calculations. The morphology, composition, and size of inclusions are analyzed by scanning electron microscopy and energy dispersive spectroscopy. The main inclusions in H13 steel without Ce content in the molten steel are MgAl2O4 spinel inclusions and multilayer carbonitrides. The carbonitrides have a multilayer structure in which MgAl2O4 acts as the nucleation core and the second layer is (Ti, V)(C, N). As the cerium content in molten steel increases from 0 to 0.03 wt%, the MgAl2O4 is effectively modified into cerium oxide (Ce–O) and cerium oxy‐sulfide (Ce–O–S), and the evolutionary process is as follows: MgAl2O4 → CeAlO3 → Ce–O and Ce–O–S. Likewise, the structure of multilayer carbonitrides in the H13 steel also changed. The MgAl2O4 and CeAlO3 act as heterogeneous nucleation cores of multilayer carbonitrides. However, Ce–O and Ce–O–S can effectively inhibit the heterogeneous nucleation of carbonitrides. The number density of large‐size carbontrides is remarkably reduced with increasing Ce content. A prediction model of optimum Ce content in molten steel is built, which has remarkable agreement with the experimental observations.

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Section: Resultsmentioning

confidence: 99%

Effect of Cerium on the Behavior of Inclusions in H13 Steel

Huang

Cheng

et al. 2018

steel research int.

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“…The SAED patterns of elongated precipitates were indexed, and the results are the same as that of region 4, which is shown in Figure 13. The elongated precipitates are M3C carbides, where M are mainly Fe [15,16]. However, the M3C carbides of region 6 are distributed mainly in lath martensite, and only a few of them are located at the martensitic lath boundaries.…”

Section: Transmission Electron Microscope Analysismentioning

confidence: 99%

Brittle Fracture Behaviors of Large Die Holders Used in Hot Die Forging

Zhang

Wang

Zhang

et al. 2017

Metals

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Brittle fracture of large forging equipment usually leads to catastrophic consequences. To avoid this kind of accident, the brittle fracture behaviors of a large die holder were studied by simulating the practical application. The die holder is used on the large die forging press, and it is made of 55NiCrMoV7 hot-work tool steel. Detailed investigations including mechanical properties analysis, metallographic observation, fractography, transmission electron microscope (TEM) analysis and selected area electron diffraction (SAED) were conducted. The results reveal that the material generated a large quantity of large size polyhedral M 23 C 6 (M: Fe and Cr mainly) and elongated M 3 C (M: Fe mainly) carbides along the martensitic lath boundaries when the die holder was recurrently tempered and water-cooled at 250 • C during the service. The large size carbides lead to the material embrittlement and impact toughness degradation, and further resulted in the brittle fracture of the die holder. Therefore, the operation specification must be emphasized to avoid the die holder being cooled by using water, which is aimed at accelerating the cooling.

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“…In the present trials, 15 large fields of view (5000×) and 15 small fields of view (10,000×) of the SEM micrographs were randomly selected in order to analyze the average diameter, the distribution, and quantity of the annealed carbides of the test steels with different additions of RE. Similarly, 15 large fields of view (100×) and 15 small fields of view (200×) of the optical microscopys (OM) were randomly selected in order to analyze the secondary dendrite arm spacing of the as-casted specimens and these statistics are based on reference [26]. In addition, the types of the annealed carbides were extensively analyzed by SEM equipped with energy dispersive X-ray spectroscopy (EDX).…”

Section: Methodsmentioning

confidence: 99%

Carbides Evolution and Tensile Property of 4Cr5MoSiV1 Die Steel with Rare Earth Addition

Liu

et al. 2017

Metals

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Studies of 4Cr5MoSiV1 die steel suggest that under appropriate conditions, additions of rare earth (RE) can enhance tensile property. This improvement is apparently due to the more uniform distribution of carbides and the enhancement of precipitation strengthening after RE additions. In this present work, the effect of the RE addition on the carbides evolution and tensile property of 4Cr5MoSiV1 steel with various RE contents (0, 0.018, 0.048 and 0.15 wt %) were systematically investigated. The two-dimensional detection techniques such as optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to investigate the carbides evolution of as-cast, annealed and tempered with RE addition. The results indicated that the carbides in 4Cr5MoSiV1 steels were modified by adding the suitable amount of RE. The eutectic structure and coarse eutectic carbides were all refining and the morphology of the annealed carbides initiated change from strip shape to ellipsoidal shape compared with the unmodified test steel (0RE). In addition, the amount of the tempered M 8 C 7 carbides increased initially and then decreased with the alteration of RE addition from 0.018 to 0.15 wt %. Notably, the tensile test indicated that the average value of ultimate tensile strength (UTS) and elongation rate of 0.048RE steel increased slightly to 1474 MPa and 15%, higher than the 1452 MPa and 12% for the unmodified test steel (0RE), respectively. Such an addition of RE (0.048 wt %) would have a significant effect on the carbides evolution of as-cast, annealed and tempered and resulting in the tensile property of 4Cr5MoSiV1 die steel.

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Precipitation Behavior of Carbides in H13 Hot Work Die Steel and Its Strengthening during Tempering

Cited by 74 publications

References 11 publications

Effect of Cerium on the Behavior of Inclusions in H13 Steel

Effect of Cerium on the Behavior of Inclusions in H13 Steel

Brittle Fracture Behaviors of Large Die Holders Used in Hot Die Forging

Carbides Evolution and Tensile Property of 4Cr5MoSiV1 Die Steel with Rare Earth Addition

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