Effect of V Contents on Microstructure and Mechanical Properties in a Fe-Cr-Ni-Mo High-Strength Steel

The effect of V contents (0, 0.03, 0.08 and 0.14%) on microstructure and mechanical properties was investigated in a Fe-Cr-Ni-Mo high-strength steel. Optical microscope (OM), electron back scattered diffraction (EBSD), transmission electron microscopy (TEM) and electron probe micro-analyzer (EPMA) were used to observe the microstructure varying in this paper. The results show that the prior austenite grain was refined obviously as increasing V content. Simultaneously, the amount of acicular ferrite (AF) increased and the size of that decreased. In addition, the size of carbide gradually decreased with increasing V content, and there appeared M2C, M6C and MC types of carbide after addition of V in the steel, while it is mainly M23C6 in the 0V steel (M is any combination of Cr, Mo, V or Mn). The strength and elongation increased gradually as increasing V content, meanwhile the impact toughness decreased gradually. The excellent combination of mechanical properties can be obtained in the steel with about 0.03% V content.

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Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0024 ◽

2016 ◽

Vol 61 (1) ◽

pp. 127-132 ◽

Cited By ~ 4

Author(s):

M. St. Węglowski ◽

M. Zeman ◽

A. Grocholewski

Keyword(s):

Mechanical Properties ◽

Impact Toughness ◽

Heat Affected Zone ◽

High Strength Steel ◽

High Strength ◽

Parent Material ◽

Cooling Time ◽

Microstructure And Mechanical Properties ◽

Ultra High Strength Steel ◽

The Impact

In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.

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Influence of coiling temperature on microstructure and mechanical properties of a hot-rolled high-strength steel microalloyed with Ti, Mo and V

Journal of Iron and Steel Research International ◽

10.1007/s42243-021-00645-8 ◽

2021 ◽

Author(s):

Zhi-xiang Fu ◽

Geng-wei Yang ◽

Ru-yang Han ◽

Yao-wen Xu ◽

Xin-ping Mao ◽

...

Keyword(s):

Mechanical Properties ◽

High Strength Steel ◽

High Strength ◽

Coiling Temperature ◽

Microstructure And Mechanical Properties ◽

Hot Rolled

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Overview of HSS Steel Grades Development and Study of Reheating Condition Effects on Austenite Grain Size Changes

Materials ◽

10.3390/ma14081988 ◽

2021 ◽

Vol 14 (8) ◽

pp. 1988

Author(s):

Tibor Kvackaj ◽

Jana Bidulská ◽

Róbert Bidulský

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

High Strength Steel ◽

Single Phase ◽

Hsla Steel ◽

High Strength ◽

Strength Properties ◽

Austenite Grain Size ◽

Austenite Grain ◽

Steel Grades

This review paper concerns the development of the chemical compositions and controlled processes of rolling and cooling steels to increase their mechanical properties and reduce weight and production costs. The paper analyzes the basic differences among high-strength steel (HSS), advanced high-strength steel (AHSS) and ultra-high-strength steel (UHSS) depending on differences in their final microstructural components, chemical composition, alloying elements and strengthening contributions to determine strength and mechanical properties. HSS is characterized by a final single-phase structure with reduced perlite content, while AHSS has a final structure of two-phase to multiphase. UHSS is characterized by a single-phase or multiphase structure. The yield strength of the steels have the following value intervals: HSS, 180–550 MPa; AHSS, 260–900 MPa; UHSS, 600–960 MPa. In addition to strength properties, the ductility of these steel grades is also an important parameter. AHSS steel has the best ductility, followed by HSS and UHSS. Within the HSS steel group, high-strength low-alloy (HSLA) steel represents a special subgroup characterized by the use of microalloying elements for special strength and plastic properties. An important parameter determining the strength properties of these steels is the grain-size diameter of the final structure, which depends on the processing conditions of the previous austenitic structure. The influence of reheating temperatures (TReh) and the holding time at the reheating temperature (tReh) of C–Mn–Nb–V HSLA steel was investigated in detail. Mathematical equations describing changes in the diameter of austenite grain size (dγ), depending on reheating temperature and holding time, were derived by the authors. The coordinates of the point where normal grain growth turned abnormal was determined. These coordinates for testing steel are the reheating conditions TReh = 1060 °C, tReh = 1800 s at the diameter of austenite grain size dγ = 100 μm.

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Physical Simulation of Weldability of Weldox 1300 Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.762.551 ◽

2013 ◽

Vol 762 ◽

pp. 551-555 ◽

Cited By ~ 3

Author(s):

Marek Stanislaw Węglowski ◽

Marian Zeman ◽

Miroslaw Lomozik

Keyword(s):

Mechanical Properties ◽

Impact Toughness ◽

Physical Simulation ◽

High Strength ◽

Parent Material ◽

Cooling Time ◽

Electron Microscopies ◽

Transmission Electron ◽

Transformation Diagrams ◽

The Impact

In the present study, the investigation of weldability of new ultra-high strength - Weldox 1300 steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on the microstructure and mechanical properties of the heat affected zone (HAZ). In the frame of these investigation the microstructure was studied by the light (LM) and transmission electron microscopies (TEM). It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite, and inside the laths the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. Mechanical properties of parent material were analysed by the tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 - 300 s. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The results show that the impact toughness and hardness decrease with the increase of t8/5 under the condition of a single thermal cycle in simulated HAZ. The continuous cooling transformation diagrams (CCT-W for welding conditions) of Weldox 1300 steel for welding purposes was also elaborated. The steel Weldox 1300 for cooling time in the range of 2,5 - 4 s showed martensite microstructure, for time from 4 s to 60 s mixture of martensite and bainite, and for longer cooling time mixture of ferrite, bainite and martensite. The results indicated that the weldability of Weldox 1300 steel is limited and to avoid the cold cracking the preheating procedure or medium net linear heat input should be used.

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Microstructure and mechanical properties of 15-5 PH stainless steel under different aging temperature

Metallurgical Research & Technology ◽

10.1051/metal/2021078 ◽

2021 ◽

Vol 118 (6) ◽

pp. 601

Author(s):

Chunhui Jin ◽

Honglin Zhou ◽

Yuan Lai ◽

Bei Li ◽

Kewei Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Aging Temperature ◽

Electron Backscatter Diffraction ◽

Lath Martensite ◽

Optical Microscope ◽

Second Phase ◽

Strengthening Mechanisms ◽

Microstructure And Mechanical Properties ◽

Transmission Electron

The influence of aging temperature on microstructure and mechanical properties of Cr15Ni5 precipitation hardening stainless steel (15-5 PH stainless steel) were investigated at aging temperature range of 440–610 °C. The tensile properties at ambient temperature of the 15-5 PH stainless steel processed by different aging temperatures were tested, and the microstructural features were further analyzed utilizing optical microscope (OM), transmission electron microscope (TEM), electron backscatter diffraction (EBSD) as well as X-ray diffraction (XRD), respectively. Results indicated the strength of the 15-5 PH stainless steel was firstly decreased with increment of aging temperature from 440 to 540 °C, and then increased with the increment of aging temperature from 540 to 610 °C. The strength and ductility were well matched at aging temperature 470 °C, and the yield strength, tensile strength as well as elongation were determined to be 1170 MPa, 1240 MPa and 24%, respectively. The microstructures concerning to different aging temperatures were overall confirmed to be lath martensite. The strengthening mechanisms induced by dislocation density and the second phase precipitation of Cu-enriched metallic compound under different aging temperatures were determined to be the predominant strengthening mechanisms controlling the variation trend of mechanical properties corresponding to different aging temperatures with respect to 15-5 PH stainless steel.

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