scholarly journals The Effect of Tempering on the Microstructure and Mechanical Properties of a Novel 0.4C Press-Hardening Steel

2019 ◽  
Vol 9 (20) ◽  
pp. 4231
Author(s):  
Oskari Haiko ◽  
Antti Kaijalainen ◽  
Sakari Pallaspuro ◽  
Jaakko Hannula ◽  
David Porter ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Low Temperature ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Hot Strip Mill ◽  
Tempering Temperature ◽  
Press Hardening ◽  
Dislocation Densities ◽  
The Impact

In this paper, the effects of different tempering temperatures on a recently developed ultrahigh-strength steel with 0.4 wt.% carbon content were studied. The steel is designed to be used in press-hardening for different wear applications, which require high surface hardness (650 HV/58 HRC). Hot-rolled steel sheet from a hot strip mill was austenitized, water quenched and subjected to 2-h tempering at different temperatures ranging from 150 °C to 400 °C. Mechanical properties, microstructure, dislocation densities, and fracture surfaces of the steels were characterized. Tensile strength greater than 2200 MPa and hardness above 650 HV/58 HRC were measured for the as-quenched variant. Tempering decreased the tensile strength and hardness, but yield strength increased with low-temperature tempering (150 °C and 200 °C). Charpy-V impact toughness improved with low-temperature tempering, but tempered martensite embrittlement at 300 °C and 400 °C decreased the impact toughness at −40 °C. Dislocation densities as estimated using X-ray diffraction showed a linear decrease with increasing tempering temperature. Retained austenite was present in the water quenched and low-temperature tempered samples, but no retained austenite was found in samples subjected to tempering at 300 °C or higher. The substantial changes in the microstructure of the steels caused by the tempering are discussed.

scholarly journals Microstructure and Mechanical Properties of Tempered Ausrolled Nanobainite Steel

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 573
Author(s):  
Jing Zhao ◽  
Dezheng Liu ◽  
Yan Li ◽  
Yongsheng Yang ◽  
Tiansheng Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Bainitic Ferrite ◽  
Energy Yield ◽  
Partial Recovery ◽  
Fracture Appearance ◽  
The Impact

The microstructures and mechanical properties of ausrolled nanobainite steel, after being tempered at temperatures in the range of 200−400 °C, were investigated in this study. After being tempered, bainitic ferrite is coarsened and the volume fraction of retained austenite is reduced. The hardness and ultimate tensile strength decrease sharply. The impact energy, yield strength, and elongation increase with elevated tempered temperature at 200–300 °C but decrease with elevated tempered temperature when the samples are tempered at 350 °C and 400 °C. The fracture appearance of all the samples after impact tests is a brittle fracture. The variation of the mechanical properties may be due to partial recovery and recrystallization.

Effect of Re-Ti compound modification on the microstructure and mechanical properties of Cr12mov steel

2020 ◽  
pp. 002072091989756
Author(s):  
Sijing Fu ◽  
Binghua Jiang ◽  
Jing Wang ◽  
Hong Cheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Optical Microscope ◽  
Test Machine ◽  
Impact Tester ◽  
Near Net Shape ◽  
The Impact ◽  
Compound Modification ◽  
Ti Content

In this paper, near net shape casting technology was used to manufacture Cr12MoV steel die modified using RE-Ti. The samples with different RE(rare earth)-Ti content were fabricated by using the induction furnace. The microstructure of the samples was analyzed by using optical microscope and scanning electron microscope. Electronic universal tensile test machine, pendulum impact tester and rockwell apparatus were utilized to test the mechanical properties of the samples. The results show that after RE-Ti compound modification, the distribution and morphology of carbide are improved, and with the Ti increase, the impact toughness significantly increases, and tensile strength has a slight increase, but hardness is almost unchanged. When Ti content is 0.6%, the impact toughness and tensile strength are 14.9 J/cm2 and 634 MPa, respectively, reaching or approaching to the mechanical properties of the forged Cr12MoV steel.

Effect of Tempering Temperature on Mechanical Properties of High Strength Wear Resistant Cast Steel

2013 ◽  
Vol 791-793 ◽  
pp. 440-443
Author(s):  
Hong Bo Li ◽  
Jing Wang ◽  
Han Chi Cheng ◽  
Chun Jie Li ◽  
Xing Jun Su
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Cast Steel ◽  
High Strength ◽  
Fracture Morphology ◽  
Temperature Quenching ◽  
Tempering Temperature ◽  
Wear Resistant ◽  
Dimple Fracture ◽  
The Impact

This paper mainly studied the high temperature quenching oil quenching, tempering temperature on the influence of high strength steel mechanical properties of wear resistant. The results show that high strength and toughness wear-resistant cast steel with 880°C× 30min after oil quenching, the hardness of 38.6HRC steel, the impact toughness value reaches 40.18J/cm2. After 200°C, 400°C and 600°C tempering, with the increase of the tempering temperature, the hardness decreased linearly, as by 600°C tempering, the hardness has been reduced to 22.3HRC. Impact toughness with the tempering temperature, the overall upward trend, the impact toughness of some reduced at 400°C, the highest impact toughness value reaches 113.34J/cm2. From the fracture morphology can be seen, with the increase of tempering temperature, ductile fracture increased, by 600°C tempering is dimple fracture, obviously can not see the traces of brittle fracture.

Investigation of Heat Treatment on Mechanical Properties of SAE4320 and SAE8620 Alloys

2013 ◽  
Vol 834-836 ◽  
pp. 816-819 ◽  
Author(s):  
Li Jun Tan ◽  
Jun Qiao Wang ◽  
Qing Qun Wang ◽  
Xin Long Chen ◽  
Si Zhu Zhou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Deformation Property ◽  
New Product ◽  
Heat Treatments ◽  
Impact Properties ◽  
The Impact

The tensile and impact properties of SAE4320 and SAE8620 alloys were investigated. Various heat treatments were applied to these two alloys, including different pre-heat treatment. The results shown that after Carburizing and Quenching, both SAE4320 and SAE8620 alloys were highly sensitively to V-notches for their impact samples. In any case, SAE4320 alloy revealed higher tensile strength, better impact toughness and deformation property. Previous work shown that after Carburizing and Quenching, the impact toughness of SAE8620 alloy was too low, the products made of it was very dangerous. Based on the results, a new advanced product was made of SAE4320 alloy instead of SAE8620 alloy. And the new product exhibited good properties. The impact value of the new product far exceeded the older products.

scholarly journals Quantitative Relationships between Mechanical Properties and Microstructure of Ti17 Alloy after Thermomechanical Treatment

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 67
Author(s):  
Yan Han ◽  
Fei Zhao ◽  
Yuan Liu ◽  
Chaowen Huang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Tensile Properties ◽  
Aging Temperature ◽  
Correlation Coefficients ◽  
Opposite Trend ◽  
Coarsening Behavior ◽  
Reduction Of Area ◽  
The Impact

In this paper, the relationships between the thermomechanical treatments (TMT), the microstructural evolution the mechanical properties of Ti17 alloy were investigated. The results indicate the coarsening behavior of lamellar α was sensitive to the aging temperature during the process of TMT. The thickness of lamellar α changed from 0.19 to 0.38 μm with an increase in the aging temperature. Moreover, both tensile properties and impact toughness vary with the thickness of lamellar α. The tensile strength increases with the increase of the thickness of lamellar α the plasticity and impact toughness the opposite trend. The quantitative investigations found that there is a linear relationship between the tensile properties and the thickness of lamellar α the tensile properties could be adjusted in the range of 1191~1062 MPa and 1163~1039 MPa to obtain ultimate tensile strength and yield strength as well as 11~16% elongation and 23~33% reduction of area by varying the thickness of lamellar α. Meanwhile, the impact toughness could be adjusted in the range of 46 ~53 J/cm2. The high correlation coefficients imply that the linear equation is reliable to describe the relationships between the mechanical properties and the thickness of lamellar α for Ti17 alloy.

Effect of Hot Isostatic Pressing on Microstructures and Mechanical Properties of IN738LC Superalloy

2017 ◽  
Vol 898 ◽  
pp. 401-406
Author(s):  
Qun Gong He ◽  
Jun Liu ◽  
Lin Xu Li ◽  
Zhen Huan Gao ◽  
Xiao Yan Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Rupture Life ◽  
Hot Isostatic Pressing ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Isostatic Pressing ◽  
Microstructures And Mechanical Properties ◽  
The Impact

The microstructures and mechanical properties of IN738LC superalloy made by investment castings followed by Hot Isostatic Pressing (HIP) treatment have been investigated. The results revealed that after HIP treatment, the microporosities have been almost removed and the density rose by 0.21%. The eutectic size became smaller and the fraction decreased. The γ' phase was more regular and also increased in size, while a large number of secondary γ' phase appeared. With HIP treatment, the impact toughness increased from 5.0J ~ 7.0J to 8J ~ 9J and tensile strength at 200°C ~ 800°C was improved by approximately 3.2%~19.7%. In addition, the ductility and the stress rupture life have also been greatly improved as well.

scholarly journals Influence of Charge Quality on Physical, Mechanical and Operational Properties of Low-Alloy Steel 30KHGSA

2020 ◽  
Vol 24 (2) ◽  
pp. 17-36
Author(s):  
N. N. Sergeev ◽  
A. N. Sergeev ◽  
S. N. Kutepov ◽  
I. V. Tikhonova ◽  
A. E. Gvozdev ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Alloy Steel ◽  
Relative Elongation ◽  
Temper Brittleness ◽  
Low Alloy Steel ◽  
Cross Sectional ◽  
Tempering Temperature ◽  
Working Length ◽  
The Impact

Purpose of reseach is to study the influence of the quality of the original charge on the complex of physical, mechanical and operational properties of structural low-alloy steel 30HGSA.Methods. As an object of research, a typical representative of low-alloy structural steels has been chosen - steel 30HGSA, smelted using metallized sponge iron pellets, ordinary scrap metal and billets obtained by the method of a boiling slag layer. In accordance with the set objectives of the study, steel 30HGSA of various melts, obtained with different charge, had the same conditions for melting, evacuation, deoxidation, casting and crystallization. The casting temperature was 1600...1620 оC and the post-vacuum treatment temperature was 1530...1560 °C. Duration of evacuation - 5 minutes. Casting of melts was carried out into cast iron molds with a siphon for 4 ... 5 minutes. Deoxidation was carried out in a ladle with aluminum in the amount of 4 ... 4.5 kg / melt. After solidification, the ingots were cooled in special wells. The ingots were cut into 3 parts: head, middle and bottom (600 × 600 mm). The middle part was then hot forged and rolled to a Ø30 mm bar. The length of the rod was 2 ... 3.4 m. After hot deformation, the rods were cooled in air.Results. Mechanical tests have been carried out. Statistical processing of experimental results has been performed. Regularities of changes in the characteristics of mechanical properties have been revealed: tensile strength, creep strength, relative narrowing of the cross-sectional area of the sample, relative elongation of the initial working length, impact strength (σВ, σ0.2, ψ, δ, aН).Conclusion. It has been found that with an increase in temperature, the mechanical properties of steel 30HGSA, smelted on various charges, decrease. It has been established that the cold brittleness threshold of 30HGSA steel is lower for purer melts on spongy iron and intermediate product KShS, the value of impact toughness at low temperatures is higher than in melting on a conventional metallized charge. Noticeable softening begins at a tempering temperature of 300 °C The temperature of the maximum tempering brittleness for steel 30HGSA, melted on a conventional metallized charge, is 550 °C It is shown that steel 30HGSA smelted with a pure original charge (spongy iron) has a lower tendency to temper brittleness than steel smelted with a conventional charge. The value of the impact toughness of the steel of this melt is higher than that of the steel of conventional melting over the entire tempering temperature range.

scholarly journals Effects of Austenitizing Temperature on Tensile and Impact Properties of a Martensitic Stainless Steel Containing Metastable Retained Austenite

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1000
Author(s):  
Biao Deng ◽  
Dapeng Yang ◽  
Guodong Wang ◽  
Ziyong Hou ◽  
Hongliang Yi
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Chromium Content ◽  
Total Elongation ◽  
X Ray Diffraction ◽  
Austenitizing Temperature ◽  
Austenite Grain Size ◽  
The Impact ◽  
M23c6 Carbides

Austenitizing temperature is one decisive factor for the mechanical properties of medium carbon martensitic stainless steels (MCMSSs). In the present work, the effects of austenitizing temperature (1000, 1020, 1040 and 1060 °C) on the microstructure and mechanical properties of MCMSSs containing metastable retained austenite (RA) were investigated by means of electron microscopy, X-ray diffraction (XRD), as well as tensile and impact toughness tests. Results suggest that the microstructure including an area fraction of undissolved M23C6, carbon and chromium content in matrix, prior austenite grain size (PAGS), fraction and composition of RA in studied MCMSSs varies with employed austenitizing temperature. By optimizing austenitizing temperature (1060 °C for 40 min) and tempering (250 °C for 30 min) heat treatments, the MCMSS demonstrates excellent mechanical properties with the ultimate tensile strength of 1740 ± 8 MPa, a yield strength of 1237 ± 19 MPa, total elongation (ductility) of 10.3 ± 0.7% and impact toughness of 94.6 ± 8.0 Jcm−2 at room temperature. The increased ductility of alloys is mainly attributed to the RA with a suitable stability via a transformation-induced plasticity (TRIP) effect, and a matrix containing reduced carbon and chromium content. However, the impact toughness of MCMSSs largely depends on M23C6 carbides.

scholarly journals Effect of Isothermal Transformation Times below Ms and Tempering on Strength and Toughness of Low-Temperature Bainite in 0.53 C Bainitic Steel

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2418
Author(s):  
Enzuo Liu ◽  
Qiangguo Li ◽  
Sufyan Naseem ◽  
Xuefei Huang ◽  
Weigang Huang
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Isothermal Transformation ◽  
Electron Back Scatter Diffraction ◽  
Bainitic Steel ◽  
Transmission Electron ◽  
The Impact ◽  
Tempering Process

This study aims to investigate the microstructures, strength, and impact toughness of low-temperature bainite obtained by isothermal transformation at temperature below Ms (Martensite Starting temperature) for different times and tempering process in 0.53 C wt% bainitic steel. By using the optical microscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), electron back scatter diffraction (EBSD), and mechanical property test, it was found that the microstructures after heat treatment consist of small amounts of martensite, fine bainite, and film retained austenite. After tempered at 250 °C for 2 h, the volume fraction of retained austenite (10.9%) in the sample treated by isothermal transformation at 220 °C for three hours is almost the same as that of the sample without tempering. In addition, the retained austenite fraction decreases with the increase of holding times and is reduced to 6.8% after holding for 15 h. The ultimate tensile strength (1827 MPa), yield strength (1496 MPa), total elongations (16.1%), and impact toughness (up to 58 J/cm2) were obtained by isothermal transformation at 220 °C for three hours and tempered at 250 °C. Whereas, the impact toughness of sample without tempering is 28 J/cm2. After holding for 15 h, the impact toughness raises to 56 J/cm2, while the ductility and strength decreases. These results indicate that the tempering process is helpful to improve the impact toughness of low-temperature bainite.

Retained Austenite Control and Extra-Cryogenic Impact Toughness of Fe-3.0%Mn Low Carbon Steel

2020 ◽  
Vol 993 ◽  
pp. 520-525
Author(s):  
Xiang Tao Deng ◽  
Xiao Lin Li ◽  
Long Huang ◽  
Zhao Dong Wang
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Low Temperature ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Uniform Elongation ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Low Temperature Impact Toughness ◽  
The Impact

The control of the retained austenite in Fe-3.0%Mn Low carbon steel by a three-step intercritical heat treatment and the low-temperature impact toughness evolution during the process were analyzed in the present study. The results indicated that the microstructure consisted intercritical ferrite, martensite/bainite and retained austenite. The distribution of carbon and manganese could improve the stability of the austenite located at the grain boundaries of prior austenite and lath boundaries of martensite. For the TRIP effect of the austenite, the excellent plasticity and low temperature toughness was obtained. The impact toughness could reach 200 J (impact energy) at －80 °C during the three-step heat treatment, and the uniform elongation could exceed at 16%.

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