Influence of high temperature deformation and double tempering on the microstructure of a H21 tool steel

Nurbanasari, Meilinda; Tsakiropoulos, P.; Palmiere, E.J.

doi:10.1016/j.msea.2013.01.067

Cited by 16 publications

(19 citation statements)

References 30 publications

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“…Tempering curves of hardness as a function of tempering temperature for austenising temperatures of 1 100 and 1 250°C are shown in Fig. 16, 25) which shows that the hardness after double tempering increased with increasing austenising temperature and decreased with increasing double tempering temperature. The highest double tempered hardness was 505 HV and was obtained after austenising at 1 250°C and double tempering at 650°C.…”

Section: The Effect Of Double Tempering On Hardnessmentioning

confidence: 95%

A Study of Carbide Precipitation in a H21 Tool Steel

2014

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Carbide precipitation in a H21 tool steel during conventional heat treatment was studied. The aim of this work was to study the exact microstructure and for better understanding of carbide formation during double tempering process of the H21 tool steel. The steel was austenised either at 1 100°C or 1 250°C for 1 hour, and water quenched. Double tempering was performed at 650, 750 and 800°C for 1 hour with air cooling in the first and second temper for each austenising temperature. The results showed that the double tempered microstructure consisted of tempered martensite, lower bainite and carbides. The current study confirmed previous findings and contributed to existing knowledge that depending on the tempering temperature, the types of carbide formed during double tempering were M2C, Fe3C, M6C and M23C6 carbides. The present study findings add substantially to our understanding of the carbide formation sequence in the H21 tool steel during double tempering. No secondary peak hardening was observed, and the highest hardness (505 HV) was obtained after austenising at 1 250°C and double tempering at 650°C, which implies that the double tempering of the H21 tool steel should be carried out below 650°C.

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Section: The Effect Of Double Tempering On Hardnessmentioning

confidence: 95%

A Study of Carbide Precipitation in a H21 Tool Steel

2014

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“…By XRD on AISI H21 (the diffraction patterns shown in fig. 19) one observed that the carbides were predominantly of M 6 C type, tungsten rich with a face centered cubic structure, and the presence of several MC type carbides [19] could also be inferred. After 100 cycles a peak appeared at 84° which could be associated with the M 23 C 6 carbide.…”

Section: Resultsmentioning

confidence: 95%

“…Nurbansari et al [19] suggested following carbide evolution: Matrix →Fe 3 C→M 6 C and an in situ transformation which occurs simultaneously Matrix → Fe 3 C →M 23 C 6 . Also, a platelet δ phase was observed at grain boundary at higher magnifications, similar aspects being presented by Kuo et al [18].…”

Section: Resultsmentioning

confidence: 99%

A Comparative Microstructure Evolution of AISI H21 and Inconel 718 in Cyclic Heating

Gheorghe¹,

Schwartz²,

Ciucă³

et al. 2018

Mat.Plast.

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The AISI H21 steel used for dies in copper hot extrusion softened only after several runs. To improve production parameters a new material was necessary for the die, and, as a first choice, Inconel 718 was preferred. Prior to adopting this material for new extrusion dies an experimental program with temperature exposure cycles was performed so as to study microstructure evolution within AISI H21 and Inconel 718. The samples were studied by optic and scanning electron microscopy (SEM) and were also submitted to X-ray diffraction (XRD) and microhardness tests. The results showed carbide coalescence, which led to softening, followed by a re-precipitation in the steel, while, in Inconel 718, the precipitation (in small amounts) of delta (ä) phase was observed.Using these results and combining them with practical experience with steel, we could predict that the Inconel 718 die performance is such that at least a double quantity of copper could be extruded per die.

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“…It is due to the high rate of nucleation of fine carbides compared to the other cryosoaking duration. The enhancement in hardness for cryotreated specimens may be due to the increased transformation of retained austenite to martensite 1,18,[29][30][31] . But due to the slightly decreased carbide density, coarsening of carbides and increased average inter-particle distance beyond 24 h cryosoaking time, the hardness slightly reduced.…”

Section: Hardnessmentioning

confidence: 99%

“…The mean size of the primary Fe 3 W 3 C carbides of as-cast H21 hot work dies steel were noted ≈ 0.3±0.1 µm. Nurbanasari et al 18 observed that after hardening at 1100 ºC followed by hot deformation at 1000 ºC for H21 hot work die steel the most dispersed and finest of Fe 3 W 3 C carbides with the average size of 0.2 µm.…”

Section: Introductionmentioning

confidence: 99%

Influence of Cryogenic Treatment on the Tribological Behaviour of AISI H21 Tool Steel

Korade

Ramana

Jagtap³

2018

Mat. Res.

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The aim of the present work was to find out the optimum cryosoaking duration of deep cryogenic treatment to reduce the wear rate. The AISI H21 hot work tool steel specimens were hardened at 1195 ºC, cryotreated at-185 ºC for 6 to 30 h, double tempered at 540 ºC and soft tempered at 100 ºC. The hardness, impact toughness, wear rate and microstructural characteristics of the cryotreated specimens were studied. Wear test parameters were optimized by using Taguchi technique. Analysis of variance and signal to noise ratio were carried out in order to find significant parameters affecting the dependent parameter. The results show that load is the most influencing parameter followed by sliding velocity and cryosoaking duration. The linear mathematical model has been developed for wear rate using a regression analysis technique which will be useful for predicting results for new experiments.

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Influence of high temperature deformation and double tempering on the microstructure of a H21 tool steel

Cited by 16 publications

References 30 publications

A Study of Carbide Precipitation in a H21 Tool Steel

A Study of Carbide Precipitation in a H21 Tool Steel

A Comparative Microstructure Evolution of AISI H21 and Inconel 718 in Cyclic Heating

Influence of Cryogenic Treatment on the Tribological Behaviour of AISI H21 Tool Steel

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