Effects of Tempering Temperature on the Microstructure and Mechanical Properties of Low Alloy Ultra-High Strength 45CrNiSiMnMoVA Steel

2021 ◽  
Vol 1036 ◽  
pp. 11-19
Author(s):  
Hong Xia Bi ◽  
Ming Hua Tang ◽  
Zhi Lan Ren ◽  
Yong Zhou
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Microstructure Evolution ◽  
Coupling Effect ◽  
Lath Martensite ◽  
High Strength ◽  
Lower Bainite ◽  
Tempering Temperature ◽  
Complex Phase ◽  
Precipitated Phases

The effects of different tempering temperatures on the microstructure evolution and mechanical properties of the new low-alloy ultra-high-strength 45CrNiSiMnMoVA steel after quenching were investigated by mechanical property tests, SEM and TEM. The results show that a complex phase organization consisting of martensite/ lower bainite of the tested steel after treated at 920°C×1h+(320~380)°C×4h was obtained, and the partition interface of the lath martensite bundle became blurred from clear with the increase of tempering temperature; In the proposed tempering temperature range, the toughness of the alloy has become better while maintain the strength without decreasing basically, and when the tempering temperature is 350°C, the alloy has the optimal comprehensive mechanical properties of strength, plasticity and toughness together. The analysis concluded that the strong toughening of the tested steel was mainly attributed to the coupling effect of the alloying elements in the steel and the composite toughening of the nano-precipitated phases, among other aspects.

Effect of Microstructural Evolution on Mechanical Properties of 55NiCrMoV7 Steel

2011 ◽  
Vol 287-290 ◽  
pp. 848-852
Author(s):  
Meng Ting Fan ◽  
Ming Yue Sun ◽  
Dian Zhong Li
Keyword(s):  
Mechanical Properties ◽  
Treatment Process ◽  
High Strength ◽  
Lower Bainite ◽  
Tempered Martensite ◽  
Tempering Temperature ◽  
Cooling Rates ◽  
Upper Bainite ◽  
Evolution Of Microstructure ◽  
Better Than

55NiCrMoV7 steel is extensively used as mould steel. However, how to obtain a product combined with both high strength and good toughness is still a problem in the heat treatment process. In current study, a series of 55NiCrMoV7 steel specimens were quenched with different cooling rates to obtain martensite, lower bainite and upper bainite, then tempered at 600°C, 620°C and 650°C, respectively. The micrographs show the evolution of microstructure with the variation of cooling rates and tempering temperature. Mechanical properties test has revealed that, 1) at the same tempering temperature, the tempered martensite has the highest strength and hardness, while the tempered lower bainite has the best impact toughness; 2) at the same ratio of yield strength to tensile strength (YS/TS), the ductility and toughness of martensite are better than that of bainite. Furthermore, fractographs of impact specimens show the ductile and brittle fracture behavior for martensite and upper bainite respectively.

Microstructure Evolution and Mechanical Properties of 67GPa•% Grade Medium Manganese Steel

2021 ◽  
Vol 1035 ◽  
pp. 404-409
Author(s):  
Zhe Rui Zhang ◽  
Ren Bo Song ◽  
Nai Peng Zhou ◽  
Wei Feng Huo
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Annealing Temperature ◽  
High Strength ◽  
Total Elongation ◽  
Manganese Steel ◽  
Experimental Steel ◽  
Medium Manganese Steel ◽  
Hot Rolled ◽  
Hot Rolled Steel

In this study, a new Fe-6Mn-4Al-0.4C high strength medium manganese hot rolled steel sheet was designed. The influence mechanism of the intercritical annealing (IA) temperature on microstructure evolution and mechanical properties of experimental steel were studied by SEM and XRD. The experimental steel was held for 30 minutes at 640°C, 680°C, 720°C, 760°C, 800°C, respectively. When the annealing temperature was 640°C, cementite particles precipitated between the austenite and ferrite phase boundary. As the annealing temperature increased, the cementite gradually dissolved and disappeared, the fraction of lamellar austenite increased significantly. When the annealing temperature is 800°C, the coarse equiaxed austenite and ferrite appeared. The yield strength (YS) decreased, the product of strength and elongation (PSE) and total elongation (TE) both increased first and then decreased, while the ultimate tensile strength (UTS) showed the opposite trend. The experimental steel exhibited excellent comprehensive mechanical properties after held at 760°C for 30 min. The UTS was 870 MPa, the YS was 703 MPa, and the TE was 77 %, the PSE was 67 GPa·%.

Microstructure and Mechanical Properties of High Strength Alloyed Steel for Aerospace Application

2018 ◽  
Vol 284 ◽  
pp. 351-356 ◽  
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength ◽  
Single Stage ◽  
The Novel ◽  
Tempering Temperature ◽  
Quenching And Partitioning ◽  
Aerospace Application ◽  
Cooling Conditions ◽  
Quenching And Tempering

The high strength aerospace steel alloyed with Cr, Mn, Si, Ni, W and Mo was studied. The austenite transformations under continuous cooling conditions were investigated using the dilatometer analysis at the cooling rates 0.1...30 °C/s. The mechanical properties of the studied steel were determined after the conventional quenching and tempering heat treatment. The dependences of the mechanical properties on the tempering temperature were obtained. The novel quenching and partitioning heat treatment was applied to the steel under consideration. The microstructure and the mechanical properties were studied after three different modes of the quenching and partitioning (QP) treatment: single-stage QP, two-stage QP and single-stage QP with subsequent tempering (QPT).

Manufacture Technique and Mechanical Properties of Kevlar/PET Composite Fabrics

2014 ◽  
Vol 910 ◽  
pp. 206-209 ◽  
Author(s):  
Jia Horng Lin ◽  
Mei Chen Lin ◽  
An Pang Chen ◽  
Ching Wen Lou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
Melting Point ◽  
High Strength ◽  
Nonwoven Fabric ◽  
Air Permeability ◽  
Kevlar Fiber ◽  
Composite Nonwoven ◽  
Composite Fabrics

With the advancement of industry, the utilization of cushion package to apply on the products of civilian, sports, electric, precise equipment increases extensively, which are brittle and vulnerable that need to be protected. In the research, the Recycled High Strength PET fiber, Recycled Kevlar fiber and low melting PET fiber are selected as materials, which the content of Recycled Kevlar fiber is stationary. The composite nonwoven fabric was manufactured by non-woven processing and subsequently estimated its stab-resistant strength and air permeability. The composite nonwoven fabric was being heat treatment which can make low melting point PET fiber bonding with other fibers in order to enhance the mechanical property of composite nonwoven fabric.

Investigation of Microstructure and Mechanical Properties of Ultra High Strength Bainitic Steel

2013 ◽  
Vol 313-314 ◽  
pp. 77-81
Author(s):  
M.H. Sheikh Ansari ◽  
M. Aghaie-Khafri
Keyword(s):  
Mechanical Properties ◽  
Alloy Steel ◽  
High Strength ◽  
Lower Bainite ◽  
Good Combination ◽  
Bainitic Steel ◽  
Low Alloy Steel ◽  
Tempered Martensite ◽  
Medium Carbon ◽  
Bainitic Steels

In this study, medium carbon low alloy steel was used to obtain bainitic structures. The lower bainite and tempered martensite-lower bainite structures were achieved by isothermal austempering and up quenching treatment, respectively. Based on the results obtained these structures showed a very good combination of strength and toughness. Furthermore, it has been shown that austenitization time and temperature, as well as austempering time and temperature play a major role in achieving ultra-high strength bainitic steels.

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.

Effect of Different Heat Treatments on Microstructure and Mechanical Properties of the Martensitic Gx12CrMoVNbN9-1 Cast Steel / Wpływ Parametrów Obróbki Cieplnej Na Mikrostrukture I Własciwosci Mechaniczne Martenzytycznego Staliwa Gx12CrMoVNbn9-1

2013 ◽  
Vol 58 (1) ◽  
pp. 25-30 ◽  
Author(s):  
G. Golanski ◽  
J. Słania
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Cast Steel ◽  
Lath Martensite ◽  
High Strength ◽  
Strength Properties ◽  
Microstructure And Mechanical Properties ◽  
Quenching And Tempering ◽  
Very High

The paper presents a research on the influence of multistage heat treatment with the assumed parameters of temperature and time on the microstructure and mechanical properties of high-chromium martensitic GX12CrMoVNbN9-1 (GP91) cast steel. In the as-cast state GP91 cast steel was characterized by a microstructure of lath martensite with numerous precipitations of carbides of the M23C6, M3C and NbC type, with its properties higher than the required minimum. Hardening of the examined cast steel contributes to obtaining a microstructure of partly auto-tempered martensite of very high strength properties and impact strength KV on the level of 9-15 J. Quenching and tempering with subsequent stress relief annealing of GP91 cast steel contributed to obtaining the microstructure of high-tempered lath martensite with numerous precipitations of the M23C6 and MX type of diverse size. The microstructure of GP91 cast steel received after heat treatment was characterized by strength properties (yield strength, tensile strength) higher than the required minimum and a very high impact energy KV. It has been proved that GP91 cast steel subject to heat treatment No. 2 as a result of two-time heating above the Ac3 temperature is characterized by the highest impact energy.

Microstructural Evolution of Medium Carbon Steels during the Quenching and Partitioning Process

2010 ◽  
Vol 654-656 ◽  
pp. 86-89 ◽  
Author(s):  
Hong Yan Li ◽  
Xue Jun Jin
Keyword(s):  
Lath Martensite ◽  
High Strength Steels ◽  
High Strength ◽  
Lower Bainite ◽  
Carbon Steels ◽  
Medium Carbon ◽  
Quenching And Partitioning ◽  
Multiphase Microstructure ◽  
Advanced High Strength Steels ◽  
Medium Carbon Steels

The “Quenching and Partitioning” (Q&P) process is a novel heat treatment designed for processing new generation advanced high strength steels (AHSS) with substantial ductility. In this study, evolution of complex microstructure for medium carbon steels during the Q&P process has been discussed in detail. Such steels have shown a complex multiphase microstructure consisted of fresh lath-martensite, fresh plate-martensite, transition carbide and/or cementite, isothermal martensite/lower bainite, and second twin-martensite after the one-step Q&P process (with the identical quenching and partitioning temperature). The morphology for the microstructure at room temperature after the two-step Q&P process (with different quenching and partitioning temperatures) demonstrated a little different. The formation of different microstructure for these two processes and their correlation with the mechanical properties are discussed.

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