Microstructural Evolution of SKD11 Tool Steel during Multi-Stage Thixoforming and Subsequent Heat Treatments

2019 ◽  
Vol 285 ◽  
pp. 45-50
Author(s):  
Yi Meng ◽  
Hui Min Zhou ◽  
Jia Lin Gan ◽  
Sumio Sugiyama

The application of semisolid forming (SSF) is inhibited significantly by the inhomogeneous distributions of microstructure and mechanical properties in the products manufactured by SSF. Beside of forming parameters including forming temperature, isothermal holding time, and forming speed, post heat treatments of SSF is one of the most important facts affecting the microstructure and mechanical properties of the SSF-manufactured products. In this study, heat treatments including annealing, quenching, and tempering different experimental conditions were conducted on the SKD11 tool steel samples manufactured by multi-stage thixoforming with different forming parameters. The microstructures in different regions of specimen processed by different experimental conditions were investigated by using a field-emission scanning electron microscopy (FE-SEM), an energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometer (XRD). Base on the results of microstructural analyses, the microstructural evolution of SKD11 tool steel during multi-stage thixoforming and subsequent heat treatments with varies experimental parameters were discussed and summarized. Meanwhile, the relationship between microstructure and mechanical properties of SKD11 tool steel processed by multi-stage thixoforming and subsequent heat treatment was also discussed.

1997 ◽  
Vol 3 (S2) ◽  
pp. 691-692
Author(s):  
K.C. Hsieh ◽  
E.A. Kenik

There has been increasing interest from industry to characterize the different precipitate distributions in ferrous materials to account for different mechanical properties that are observed. For this study, two different heat treatments were chosen for the experimental S5 tool steel, modified to have 0.24 wt% C. Alloy S5-1 received 1 hour of austenitizing at 970°C, was quenched at rate of 140°C/s and tempered for 1 hour at 200°C. Alloy S5-2 received 40 minutes of austenitizing at 940°C, was quenched at rate of 16°C/s and tempered for 1 hour at 200 °C. In this relatively low hardenability steel, both S5-1 and S5-2 show mixed microstructures of tempered martensite and bainite (Fig. 1, 2). Not surprisingly, the slower cooling rate for S5-2 created an alloy with inferior microstructure and mechanical properties. Even though these differences in precipitate distributions, could not directly account for differences in mechanical properties, it is of interest to study how the different heat treatments affected the precipitate distributions in S5-1 and S5-2.


2014 ◽  
Vol 217-218 ◽  
pp. 53-60 ◽  
Author(s):  
Yi Meng ◽  
Sumio Sugiyama ◽  
Jun Yanagimoto

Owing to the phase segregation occurred during semisolid process, the ferroalloys products manufactured by semisolid process always exhibit inhomogeneous microstructure and poor mechanical properties. In this study, the post heat treatments including quenching treatment and tempering treatment with various processing parameters were carried out to improve the quality of Cr-V-Mo steel (JIS SKD61, AISI H13, DIN 1.2344) which processed by RAP (recrystallization and partial melting) processed. The microstructural characteristics (phase transformation, morphology of carbides, and distribution of alloying elements) and mechanical properties (hardness, tensile strength, elongation, impact toughness, and resistance to high-temperature wear) of specimens processed by RAP and heat treatments under various experimental conditions were investigated experimentally. Being quenched from 1050 °C after isothermal holding for 480 s and then tempered twice at 560 °C for 2 h, the microstructural evolution took placed in both former solid-phase and liquid-phase regions of the RAP-processed Cr-V-Mo steel specimen. During this post heat treatment strategy, the weakening of phase segregation, the redistribution of carbides, and the release of residual stress occurred and resulted in the improvement of microstructure and a good combination of mechanical properties.


2016 ◽  
Vol 61 (2) ◽  
pp. 761-766 ◽  
Author(s):  
A. Zieliński ◽  
M. Sroka ◽  
A. Hernas ◽  
M. Kremzer

Abstract The HR3C is a new steel for pressure components used in the construction of boilers with supercritical working parameters. In the HR3C steel, due to adding Nb and N, the compounds such as MX, CrNbN and M23C6 precipitate during service at elevated temperature, resulting in changes in mechanical properties. This paper presents the results of microstructure investigations after ageing at 650, 700 and 750 °C for 5,000 h. The microstructure investigations were carried out using scanning and transmission electron microscopy. The qualitative and quantitative identification of the existing precipitates was carried out using X-ray analysis of phase composition. The effect elevated temperature on microstructure and mechanical properties of the examined steel was described.


2017 ◽  
Vol 898 ◽  
pp. 638-642 ◽  
Author(s):  
Dong Xu Qiao ◽  
Hui Jiang ◽  
Xiao Xue Chang ◽  
Yi Ping Lu ◽  
Ting Ju Li

A series of refractory high-entropy alloys VTaTiMoAlx with x=0,0.2,0.6,1.0 were designed and produced by vacuum arc melting. The effect of added Al elements on the microstructure and mechanical properties of refractory high-entropy alloys were investigated. The X-ray diffraction results showed that all the high-entropy alloys consist of simple BCC solid solution. SEM indicated that the microstructure of VTaTiMoAlx changes from equiaxial dendritic-like structure to typical dendrite structure with the addition of Al element. The composition of different regions in the alloys are obtained by energy dispersive spectroscopy and shows that Ta, Mo elements are enriched in the dendrite areas, and Al, Ti, V are enriched in inter-dendrite areas. The yield strength and compress strain reach maximum (σ0.2=1221MPa, ε=9.91%) at x=0, and decrease with the addition of Al element at room temperature. Vickers hardness of the alloys improves as the Al addition.


2012 ◽  
Vol 628 ◽  
pp. 482-485
Author(s):  
Yulia A. Lukina ◽  
Andrey V. Stepanov ◽  
Evgeny N. Bobrov

The paper deals with manufacturing technology for the forged rolls and sleeves from adamite steel at Electrostal Plant of Heavy Machinery (JSC «EZTM»). The influence of different heat treatments on microstructure and mechanical properties of the level of adamite steel is presented.


2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.


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