The Effect of Cooling Rate and Overaging Time on the Mechanical Properties of a Ultra-Low Carbon Auto Steel

2014 ◽  
Vol 1004-1005 ◽  
pp. 179-182
Author(s):  
Fang Fang ◽  
Li Bo Pan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Cooling Rate ◽  
Aging Time ◽  
Low Carbon ◽  
Research Results ◽  
Dipping Process ◽  
Fast Cooling ◽  
Process Simulator

A series of annealing parameters including the cooling rate and overaging time, especially ultra high cooling rate of a ultra-low carbon auto steel were conducted on HDPS (hot dipping process simulator) in experiment. The research results show that, when samples were conducted under extra fast cooling rate higher than 30 °C/s, yield and tensile strength almost changed not when cooling rate increased from 30 to 50 °C/s, as cooling rate reached 90 °C/s, the strength and elongation changed more rapidly. When the overaging time changed from 130 to 300 s, the elongation was more sensitive, changed from 19.7 to 25.6 %. Yield and tensile strength were not sensitive when aging time was below 213 s, but with increasing aging as high as 300 s, the yield strength decreased 11 MPa, and tensile strength decreased 21 MPa.

Effect of the Cooling Rate on Crystallinity and Tensile Strength of Two PVDF Grades

2015 ◽  
Author(s):  
Caroline Slikta Velloso ◽  
Geovanio Lima de Oliveira ◽  
Christine Rabello Nascimento ◽  
Celio Albano da Costa Neto
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cooling Rate ◽  
Vinylidene Fluoride ◽  
Processing Technique ◽  
Processing Conditions ◽  
Poly Vinylidene Fluoride ◽  
Fast Cooling

The PVDF (poly(vinylidene fluoride)) is the recommended material for pressure barrier application when the temperature is above 90 C and below 130 C (API Specification 17J). Two grades of PVDFs used in flexible raisers were processed. The grades selected were those for extrusion, but they were compression molded instead. The processing conditions were the same for each grade, from slow to fast cooling rate. The results allowed the evaluation of their performance using a simpler processing technique and, also, to observe how the mechanical properties varied with the cooling rate applied.

Influences of Hot Rolling Conditions on the Microstructure and Mechanical Properties of Low-Alloy Steel

2011 ◽  
Vol 391-392 ◽  
pp. 214-218
Author(s):  
Hai Shen Sun ◽  
Guo Ping Li ◽  
Wen Chen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Cooling Rate ◽  
Second Phase ◽  
Elongation Ratio ◽  
Technological Parameters ◽  
Microstructure And Mechanical Properties ◽  
Test Steel ◽  
Hot Rolling Conditions

The thermomechanical control processing (TMCP) was conducted through the adjustment of the rolling technological parameters to the test steel. The influence of the finishing temperature, cooling rate and alloying elements to the microstructure and mechanical properties was investigated by comprehensive utilization of grain refining strengthening and second phase strengthening.The results show that the microstructure was mainly composed of bainite, ferrite and second phase TiC; at the finishing temperature of 870°C, the yield strength was 596.7 MPa, the tensile strength reached 748.5 MPa, the elongation ratio was 20.17%; at high cooling rate of 16°C/s, the yield strength achieved 616.7 MPa, the tensile strength reached 785.5 MPa, the tensile ratio reduced for 0.78, and the elongation ratio enhanced to 20.92%. And the quantity of bainite increased with the raise of finishing temperature from 800°C to 870°C, which improved the hardness and wear resistance of the steel.

Effect of Tempering Temperature on the Microstructure and Mechanical Properties of a 0.1C Steel with High Strength and Low Yield Ratio

2012 ◽  
Vol 535-537 ◽  
pp. 601-604
Author(s):  
Wen Hao Zhou ◽  
Hui Guo ◽  
Cheng Jia Shang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Major Change ◽  
Total Elongation ◽  
Yield Ratio ◽  
High Yield ◽  
Low Carbon ◽  
Tempering Temperature ◽  
Microstructure And Mechanical Properties

The influence of tempering temperature on the microstructure and mechanical properties of low carbon low alloy steel was investigated. The results show that tempering temperature has considerable influence on both yield strength and tensile strength. With the increase in tempering temperature, the yield strength increases first and then decreases after it reaches the highest point at 600°C with a strength of 843MPa, while the tensile strength decreases fastly from 550°C to 650°C and keeps stable after increasing drastically at 720°C. The yield ratio is about 0.60 except at 600°C and 650°C with a high yield ratio of 0.90, while the total elongation has little change. It is concluded that the major change of mechanical properties after tempering has a connection with the decomposition of M/A(martensite/austenite) islands, the recovery of dislocations and the precipitation of alloy elements.

scholarly journals Effect of Heat Treatment on the Mechanical Properties of Two-Phase Titanium Alloy Ti6al7nb/ Wpływ Obróbki Cieplnej Na Własności Mechaniczne Dwufazowego Stopu Tytanu Ti6al7nb

2014 ◽  
Vol 59 (4) ◽  
pp. 1713-1716 ◽  
Author(s):  
R. Dąbrowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Yield Strength ◽  
Cooling Rate ◽  
Strength Properties ◽  
Two Phase ◽  
Impact Tests ◽  
Alloy Heat

Abstract Mechanical properties of the two-phase titanium alloy Ti6Al7Nb, after the heat treatment based on soaking this alloy in the α + β range, cooling in water or oil and ageing at two selected temperatures, were determined in the hereby paper. The alloy mechanical properties were determined in tensile and impact tests, supported by the fractographic analysis of fractures. In addition, its hardness was measured and the analysis of changes occurring in the microstructure was performed for all variants of the alloy heat treatment. Regardless of the applied cooling rate of the alloy, from a temperature of 970°C followed by ageing at 450 and 650°C, none essential changes were noticed in its microstructure. It was shown that applying less intensive cooling medium (oil) instead of water (before tempering) decreases strength properties indicators, i.e. tensile strength and yield strength as well as hardness (only slightly). The decrease of the above mentioned indicators is accompanied by an increase of an elongation and impacts strength. Fractures of tensile and impact tests are of a ductile character regardless of the applied heat treatment.

Microstructures and Mechanical Properties of High Strength Low Carbon Bainitic Steel

2015 ◽  
Vol 817 ◽  
pp. 257-262 ◽  
Author(s):  
Xiao Long Yang ◽  
Yun Bo Xu ◽  
Xiao Dong Tan ◽  
Yong Mei Yu ◽  
Di Wu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Impact Energy ◽  
Bainitic Steel ◽  
Cooling Temperature ◽  
Fast Cooling ◽  
Microstructures And Mechanical Properties ◽  
The Impact ◽  
Strength And Toughness

Based on TMCP and UFC technology, the microstructures and mechanical properties of 0.05% C bainitic steel were studied in this paper. The bainite morphology and precipitation within bainite lath were observed by SEM and TEM, and the mechanical properties of bainitic steel were measured by tensile and impact test. The results showed that the yield and tensile strengths of steel were 713 MPa and 891 MPa respectively, and the elongation was 15.8% with impact energy of 95J at the temperature of-20°C as the final cooling temperature in hot rolling of 550°C. For comparison, the steel obtained the yield strength of 725 MPa, tensile strength of 930 MPa and elongation of 18% as the final cooling temperature of 450°C. However, the impact energy of steel was 195J at the temperature of-20°C. While at the same final cooling temperature of 450°C, the fast cooling-holding temperature-fast cooling was applied to experimental steel with a faster cooling rate of 50°C/s, hence the steel acquired the yield strength of 845 MPa, tensile strength of 1037 MPa, and elongation of 15.5% with impact energy of 168J at the temperature of-20°C. The strength and toughness of 0.05%C bainitic steel is related to the bainite morphology and precipitation distribution. Hence, the strength and toughness can be improved by control the different cooling processes for adjusting the content of lath bainite, distribution of granular bainite and precipitation.

Thermo-Mechanically Controlled Processed Ultrahigh Strength Steels

2014 ◽  
Vol 783-786 ◽  
pp. 685-691
Author(s):  
Subrata Chatterjee ◽  
S.K. Ghosh ◽  
P.S. Bandyopadhyay
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
High Strength Steel ◽  
Bainitic Ferrite ◽  
High Strength ◽  
Bearing Steel ◽  
Pressure Vessels ◽  
Low Carbon ◽  
Ultra High Strength Steel

A low-carbon, titanium and niobium (Ti-Nb) bearing and a low-carbon titanium, niobium and copper (Ti-Nb-Cu) bearing ultra high strength steel have been thermo-mechanically processed on a laboratory scale unit. Evolution of microstructure and mechanical properties of the above air cooled steels have been studied at different finish rolling temperatures (FRTs). Microstructural characterization reveals largely a mixture of granular bainite and bainitic ferrite along with the precipitation of microalloying carbide/carbonitride particles and/or Cu-rich precipitates. (Ti-Nb) bearing steel yields higher yield strength (1114-1143 MPa) along with higher tensile strength (1591-1688 MPa) and moderate ductility (12-13%) as compared to (Ti-Nb-Cu) bearing steel having yield strength (934-996 MPa) combined with tensile strength (1434-1464 MPa) and similar ductility (13%) for the selected range of 850-750°C FRT. Due to higher strength-ductility combinations, these present investigated steels can be regarded as the replacement material for ballistic applications as well as other sectors like defense, pipeline, cars, pressure vessels, ships, offshore platforms, aircraft undercarriages and rocket motor casings etc. Key words: Thermo-mechanical controlled processing, ultra high strength steel, microstructure, mechanical properties.

The Structure and Mechanical Properties of Al-7%SiMg Alloy Treated with a Homogeneous Modifier

2010 ◽  
Vol 163 ◽  
pp. 183-186 ◽  
Author(s):  
Tomasz Lipiński
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Abrasive Wear ◽  
Cooling Rate ◽  
Brinell Hardness ◽  
Physical And Mechanical Properties ◽  
Percentage Elongation ◽  
Fast Cooling

Results of studies on the modification of Al-7%SiMg alloy with a homogeneous modifier obtained by fast cooling of homogeneous modifiers at V=200 K/s are presented in the paper. Homogeneous modifiers are additions designed for modification of the alloys from which they were obtained at 0, 7, 12 and 20% Si. The components were put into a crucible containing liquid Al-Si alloy and kept there for one minute. The effects of cooling rate and w/w concentration of the modifier in the melt on structure and tensile strength, percentage elongation, Brinell hardness, abrasive wear are illustrated graphically. The analysis of the process of hypo-eutectic Al-Si alloy modification with a homogeneous modifier obtained from treated alloy by fast cooling shows that this modifying addition affected structural,physical and mechanical properties of Al-7%SiMg alloy.

Investigation on the Microstructure and Mechanical Properties of T23 Steel during High Temperature Aging

2020 ◽  
Vol 993 ◽  
pp. 575-584
Author(s):  
Bao Liang Shi ◽  
Chao Zhang ◽  
Yao Wen Tang ◽  
Guo Jie Wei ◽  
Yan Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Aging Time ◽  
Size Increase ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
High Temperature Aging ◽  
Temperature Aging

The changes of the microstructure and mechanical properties of T23 steel were investigated during high temperature aging at 625 °C up to 3000 h. The results showed that the bainitic lath microstructure first decreased and then totally disappeared with the increase of aging time, the size of the carbides gradually increased and the recovery occurred after aging for 1000 h. The contents of W, Mo elements in the matrix after aging for 3000 h were remarkably decreased by 27.6% and 45% compared with the as-received state. However, no M6C carbides formed in spite of the obvious desolution transformation of W, Mo. Both the yield strength and the tensile strength at room and high temperature were decreased with the increase of aging time at 625 °C, and the tensile strength at high temperature after aging for 3000 h exhibited the largest of decline compared with the as-received state. The main reasons for the decrease of the mechanical properties related to the microstructure variations, such as the size increase of the M23C6 carbides, the dissolution of the bainite lath microstructure and the occurrence of the recovery. Meanwhile, the desolution of W, Mo elements plays an important role in the decrease of the mechanical properties.

Effect of laser inclination angle on mechanical properties of Hastelloy X processed by selective laser melting

2021 ◽  
Vol 63 (1) ◽  
pp. 10-16
Author(s):  
Zong Xuewen ◽  
Zhang Jian ◽  
Fu Hanguang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Temperature Field ◽  
Yield Strength ◽  
Cooling Rate ◽  
Selective Laser Melting ◽  
Inclination Angle ◽  
Laser Melting ◽  
Cooling Rates ◽  
Hastelloy X

Abstract Selective laser melting at various laser inclination angles was used to prepare Hastelloy X alloy specimens. The morphology, fracture, tensile strength, stress, and strain of Hastelloy X alloy specimens were studied using optical microscopy, scanning electron microscopy, and a tensile tester. The temperature field of the manufacturing process was analyzed based on finite element analysis, and the internal relationship between the temperature field and the process was constructed in terms of cooling speed. The results show that the temperature field is a dynamic process with a high cooling rate; the average cooling rate reaches 3.23 × 106 °C × s−1. The greater the inclination angle, the greater the thermal gradient, resulting in higher cooling rates. Due to the cross-influence of grain refinement at high cooling rates and residual stress, the tensile strength and yield strength of Hastelloy X alloy showed first increasing and then decreasing trends with respect to inclination angle. However, at an inclination angle of 30°, the voids and crack defects of Hastelloy X alloy fractures were reduced, and the tensile strength and yield strength reached 881.38 and 701.60 MPa, respectively. At this angle, the mechanical properties were excellent and met the requirements of the aviation industry.

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