scholarly journals The effect of flame straightening on the microstructure and mechanical properties of different strength steels

2021 ◽  
Author(s):  
László Gyura ◽  
Marcell Gáspár ◽  
András Balogh
Keyword(s):  
Mechanical Properties ◽  
High Sensitivity ◽  
High Strength ◽  
Water Cooling ◽  
Experimental Conditions ◽  
Physical Simulations ◽  
Lower Temperature Range ◽  
Lower Temperature ◽  
Subcritical Temperature ◽  
Supercritical Temperature

AbstractIn many cases, flame straightening is unavoidable after welding for the reduction of deformation. Due to the not very concentrated heat source, the process can cause significant changes in the microstructure, especially in high strength and wear-resistant steels. Due to their different physical properties, the effects vary depending on the flammable gases (acetylene, propane). The situation is complicated by the fact that the manual technology carries a risk of overheating, which can have detrimental effects on the mechanical properties. During our experiments, three steels are investigated (S355J2 + N, XAR400, S960QL). The thermal cycles for the physical simulations were determined by thermocouple measurement during real experimental conditions. Three peak temperatures (1000 °C, 800 °C and 675 °C) and two types of industrial cooling conditions (air and water cooling) were studied. The samples were examined by optical microscopy tests, hardness testing and Charpy V-notch impact tests. During straightening the XAR400 showed high sensitivity to softening even in the lower temperature range, while hardening occurred in the S960QL steel at a higher peak temperature values during water cooling. The inter- and supercritical temperature should be avoided in all steels; however, the subcritical temperature can be beneficial to the toughness properties of the S960QL and XAR400.

Study on Metallography Test of the Steel SPV490 for Atmospheric Storage Tank After Fire

2016 ◽  
Author(s):  
Zhou Fang ◽  
Weiwei Hu ◽  
Deyu Liu ◽  
Guanghai Li ◽  
Zhe Wang
Keyword(s):  
Mechanical Properties ◽  
Working Conditions ◽  
Storage Tank ◽  
High Strength ◽  
Air Cooling ◽  
Microscopic Structure ◽  
Water Cooling ◽  
Storage Tanks ◽  
Fire Temperature ◽  
Optical Microstructure

The fire process was simulated by the heat treatment to the Steel SPV490 of atmospheric storage tank, thereby obtaining the metal specimens in different fire temperature, holding time, and cooling modes. And as the temperature increases, the microscopic structure of Steel SPV490 changes under different working conditions, which could be shown in optical microstructure pictures after doing the interception, inlay, polishing, finishing to the specimens. The result shows that, the mechanical properties of the Steel SPV490 for storage tank changes as the temperature rising from the microscopic view. Nodulizing of the cementite in pearlite occurs, and the strength decreases when the high strength steel SPV490 of large atmospheric storage tanks under air cooling condition below 700 °C, however, it equivalents to the normalizing process, as the sorbite occurs in the steel, and the strength increases a bit when the temperature is above 900 °C. The water-cooling of steel SPV490 above 900 °C equivalents to the process of quenching. The occurrence of martensitic substantially increases the strength and the brittleness, and the elongation decreases rapidly.

A study on the mechanical properties of forged high chrome steel heat resistant materials

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040036
Author(s):  
Il Heon Jeong ◽  
Yeong Min Park ◽  
Jae Uk Yoo ◽  
Tae Gyu Kim
Keyword(s):  
Mechanical Properties ◽  
Acidic Solution ◽  
High Strength ◽  
Tempering Temperature ◽  
Chrome Steel ◽  
High Durability ◽  
Heat Treated ◽  
Engine Blade ◽  
Lower Temperature ◽  
Steel Heat

High chrome steel (12 Cr-steel) is the material found in engine blade which required high durability and long service life at high temperatures. Therefore, it is important to produce durable and high strength 12 Cr-steel. In this study, effect of different tempering temperature on microstructure of 12 Cr-steel specimens were investigated. First, the specimens were heat treated to 1070[Formula: see text]C and quenched in an acidic solution. Then they were tempered at different temperature at 470[Formula: see text]C and 690[Formula: see text]C. Analyses on mechanical properties such as hardness, yield strength, tensile stress were performed. It is found that specimen at lower temperature (470[Formula: see text]C) has improved mechanical properties.

FANSTEEL 291 METAL

Alloy Digest ◽  
1973 ◽  
Vol 22 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Base Alloy ◽  
Weight Ratio ◽  
High Strength ◽  
Heat Treating ◽  
Temperature Range ◽  
Temperature Performance ◽  
Lower Temperature Range ◽  
Lower Temperature

Abstract FANSTEEL 291 METAL is a columbium-base alloy that can be readily fabricated, machined and welded. It is used in the high-temperature range 2800-3500 F where excellent strength-to-weight ratio can be used to advantage. It is also used in the lower temperature range 2000-2700 F because of its availability and fabricability which may be of more importance than high strength alone. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as heat treating, machining, and joining. Filing Code: Cb-20. Producer or source: Fansteel Metallurgical Corporation.

The Effects of Thermomechanical Processing on the Microstructure and Mechanical Properties of Ultra-High Strength Dual Phase Steel

2013 ◽  
Vol 631-632 ◽  
pp. 666-669
Author(s):  
Zhuang Li ◽  
Di Wu ◽  
Wei Lv ◽  
Shao Pu Kang ◽  
Zhen Zheng
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
Thermomechanical Processing ◽  
High Strength ◽  
Transformation Products ◽  
Dual Phase ◽  
Laminar Cooling ◽  
Controlled Cooling ◽  
Hot Rolling Mill ◽  
Lower Temperature

In this paper, ultra-high strength dual phase steel was investigated. Thermomechanical processing was conducted by using a laboratory hot rolling mill. The results have shown that the main transformation products at three different kinds of thermomechanical processing were ferrite, bainite, and small amounts of martensite. Laminar cooling led to ferrite grain refinement. The mechanical properties of specimen 1 which was controlled cooling after a relative lower temperature rolling are much higher than that of specimen 2. The presence of martensite islands and precipitates contributed to the enhancement of strength of the present steel. And the presence of retained austenite resulted in higher toughness. As a result, these specimens exhibited satisfactory mechanical properties.

scholarly journals Mechanical Properties and Fractographic Analysis of High Manganese Steels After Dynamic Deformation Tests

2014 ◽  
Vol 59 (3) ◽  
pp. 1193-1197 ◽  
Author(s):  
M.B. Jabłońska
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Test ◽  
High Sensitivity ◽  
High Strength ◽  
Dynamic Mechanical Properties ◽  
High Manganese ◽  
High Manganese Steels ◽  
Conducting Research ◽  
Manganese Steels

Abstract Since few years many research centres conducting research on the development of high-manganese steels for manufacturing of parts for automotive and railway industry. Some of these steels belong to the group of AHS possessing together with high strength a great plastic elongation, and an ideal uniform work hardening behavior. The article presents the dynamic mechanical properties of two types of high manganese austenitic steel with using a flywheel machine at room temperature with strain rates between 5×102÷3.5×103s?–1. It was found that the both studied steels exhibit a high sensitivity Rm to the strain rate. With increasing the strain rate from 5×102 to 3.5×103s?–1 the hardening dominates the process. The fracture analysis indicate that after dynamic test both steel is characterized by ductile fracture surfaces which indicate good plasticity of investigated steels.

Passive Laser Assisted Bending of Ultra-High Strength Steels

2011 ◽  
Vol 418-420 ◽  
pp. 1542-1547 ◽  
Author(s):  
Antti Järvenpää ◽  
Pentti Karjalainen ◽  
Kari Mäntyjärvi
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Laser Heat ◽  
Heat Treated ◽  
Significant Strength ◽  
Steel Grades ◽  
Lower Temperature Range ◽  
Ultra High Strength Steels ◽  
Lower Temperature ◽  
Heating Up

Formability of ultra-high strength steels is poor causing problems in bending and stretch forming. The target of this work was to improve the formability of ultra-high strength steel sheets by controlled local laser heat treatments. Three steel grades, a bainitic-martensitic 4 mm DQ960 and two martensitic WR500 with 6 mm and 10 mm thicknesses were heated by controlled thermal cycles using a 4 kW Yb:Yag –laser, followed by self-cooling. Sheets with the thicknesses of 4 and 6 mm were treated on one side only by heating up to the austenitizing temperature. The 10 mm thick WR500 sheet was heat treated separately on the both surfaces by heating to a lower temperature range to produce a shallow tempered layers. The tensile and bendability tests as well as hardness measurements indicated that laser heat treatment can be used to highly improve the bendability locally without significant strength losses.

scholarly journals The Influence of Nanohydroxyapatite on the Thermal, Mechanical, and Tribological Properties of Polyoxymethylene Nanocomposites

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Kinga Pielichowska ◽  
Dariusz Bieliński ◽  
Michał Dworak ◽  
Ewelina Kilian ◽  
Beata Macherzyńska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Glass Transition ◽  
Indentation Test ◽  
Degree Of Crystallinity ◽  
Test Results ◽  
Mechanical And Tribological Properties ◽  
Ultrasonic Methods ◽  
Lower Temperature Range ◽  
Lower Temperature

The influence of nanohydroxyapatite on the glass transition region and its activation energy, as well as on the tribological and mechanical properties of polyoxymethylene nanocomposites, was investigated using DMA, TOPEM DSC, nanoindentation, and nondestructive ultrasonic methods. It was found that the glass transition for unmodified POM was in the lower temperature range than in POM/HAp nanocomposites. Moreover,ΔCpand activation energy were larger for POM/HAp nanocomposites. Friction coefficient was higher for POM/HAp nanocomposites in comparison to both POM homopolymer and POM copolymer. Simultaneously, the indentation test results show that microhardness is also higher for POM/HAp nanocomposites than for POM. From ultrasonic investigations it was found that the highest values of both longitudinal and transverse propagation waves and Young’s and shear modulus for POM homopolymer (DH) and POM copolymer T2H and their nanocomposites can be attributed to their higher degree of crystallinity in comparison to UH copolymer. Moreover, for POM/HAp nanocomposites with 5% of HAp, ultrasonic longitudinal wave velocity was almost constant even after 1000000 mechanical loading cycles, evidencing an enhancement of mechanical properties by HAp nanoparticles.

scholarly journals Effect of Pre-Stretch on the Precipitation Behavior and the Mechanical Properties of 2219 Al Alloy

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2101
Author(s):  
Guo-Ai Li ◽  
Zheng Ma ◽  
Jian-Tang Jiang ◽  
Wen-Zhu Shao ◽  
Wei Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
High Strength ◽  
Age Hardening ◽  
Al Alloy ◽  
Precipitation Behavior ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Lower Temperature ◽  
Age Strengthening

The influence of pre-stretch on the mechanical properties of 2219 Al alloys sheets were systematically investigated, with the aim of examining the age-strengthening in parts draw-formed from as-quenched sheets. The precipitation was characterized based on differential scanning calorimetry (DSC) analysis and transmission electron microscope (TEM) observation of specimens of as-quenched and quenched-stretched condition to address the influence of pre-stretching. A tensile test was performed to evaluate the effect on mechanical properties. The introduction of pre-stretching endues increased yield strength (YS) and thus can be helpful to exert the potential of the alloy. Peak YS of 387.5 and 376.8 MPa are obtained when specimens pre-stretched for 10% are aged at 150 and 170 °C, respectively, much higher than that obtained in the non-stretched specimens (319.2 MPa). The precipitation of Guinier-Preston zone (G.P. zones) and the transition to θ″ shifts to a lower temperature when pre-stretched is performed. The high density of dislocations developed during the stretching contributes to the acceleration in precipitation. Quench-stretched specimens present a much quicker age-hardening response at the beginning stage, which endue higher peaked yield strength. The yield strength, however, decrease much more quickly due to the recovery that occurs during the aging processes. The study suggested the feasibility of aging draw-formed components of 2219 Al alloy to obtain high strength.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

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