Characterization of the multi-pass weld metal and the impact of retained austenite obtained through intercritical heat treatment on low temperature toughness

2016 ◽  
Vol 649 ◽  
pp. 282-292 ◽  
Author(s):  
X.L. Wang ◽  
X.M. Wang ◽  
C.J. Shang ◽  
R.D.K. Misra
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Weld Metal ◽  
Retained Austenite ◽  
Intercritical Heat Treatment ◽  
Low Temperature Toughness ◽  
The Impact

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%.

Characterization of silicate sensors on Low Temperature Cofire Ceramic (LTCC) substrates using DSC and XRD techniques

2012 ◽  
Vol 2012 (1) ◽  
pp. 000598-000603
Author(s):  
Mary Ruales ◽  
Kinzy Jones
Keyword(s):  
Low Temperature ◽  
Phase Diagrams ◽  
Cost Effective ◽  
Microelectronics Packaging ◽  
Design Structure ◽  
Recovery Times ◽  
Response And Recovery ◽  
Xrd Techniques ◽  
The Impact

Characterization of Silicate sensors using Differential Scanning Calorimeter (DSC), X-ray Diffraction (XRD) and Scanning Electron microscopy (SEM) is presented. These silicate sensors are based on three primary materials: Li2SiO3, K2SiO3, and CaSiO3. Silicate powders were transform into adequate inks that were added to a Low Temperature Cofire Ceramic (LTCC) substrates with thick film technology using screen printing which continues to offer innovative and cost effective solutions to the increasing demands for higher circuit densities. These silicate sensors are low power-high temperature heated ceramic sensors to detect halogen gases. Every sensor responded to the gas showing stability and reproducibility. Phase diagrams for these silicates were used to produce different combinations. The use of the eutectoid point in the phase diagrams was critical to reduce the operating temperature. Testing and characterization of these silicate sensors is presented. The impact of various parameters (e.g. materials design, structure, properties, performance and processing) for the sensors including their relationships for electronic packaging was reviewed and it was found critical to determine the microelectronics packaging reliability and integrity. The fundamentals of the sensor behavior including the sensitivity as well as response and recovery times were also determined.

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.

The role of addition of Ni on the microstructure and mechanical behaviour of C-Mn weld metals

Exacta ◽  
2008 ◽  
Vol 5 (1) ◽  
Author(s):  
Vicente Braz da Trindade ◽  
João Da Cruz Payão ◽  
Luís Felile Guimarães Souza ◽  
Ronaldo Da Rocha Paranhos
Keyword(s):  
Heat Treatment ◽  
Weld Metal ◽  
Nickel Content ◽  
Stress Relief ◽  
Impact Testing ◽  
Microstructural Refinement ◽  
Weld Metals ◽  
The Impact ◽  
Submerged Arc

The aim in this work is to study the influence of nickel content (as-welded state and after stress relief heat treatment) on the microstructure and toughness of CMn weld metals obtained with submerged arc welding. The nickel content vary between 0.50 wt.% and 3.11 wt.%. The microstructures were observed using optical microscopy (OM) and scanning electron microscopy (SEM). The toughness was evaluated by Charpy-V impact testing in samples cut transversally to the weld bead. The impact energy showed that nickel content up to 1 wt.% improves the toughness due to the increase of the acicular ferrite (AF) content and microstructural refinement. On the other hand, higher nickel contents have a deleterious effect on the toughness due to the presence of the microconstituent martensite-austenite (M-A) in the weld metal. The stress relief heat treatment did not improve too much the weld metal toughness, even the M-A suffering decomposition (ferrite+carbide). This may be explained by the precipitation of carbides along the boundaries of the ferrite.

Effect of Heat Treatment Technique on the Low Temperature Impact Toughness of Steel EQ70 for Offshore Structure

2017 ◽  
Vol 36 (8) ◽  
pp. 825-830 ◽  
Author(s):  
Su-Fen Tao ◽  
Yun-Jin Xia ◽  
Fu-Ming Wang ◽  
Jie Li ◽  
Ding-Dong Fan
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Impact Toughness ◽  
Treatment Technique ◽  
Offshore Structure ◽  
Treatment Techniques ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness ◽  
The Impact ◽  
Quenching And Tempering

AbstractCircle quenching and tempering (CQ&T), intercritical quenching and tempering (IQ&T) and regular quenching and tempering (Q&T) were used to study the influence of heat treatment techniques on the low temperature impact toughness of steel EQ70 for offshore structure. The steels with 2.10 wt. % Ni (steel A) and 1.47 wt. % Ni (steel B) were chosen to analyze the effect of Ni content on the low temperature impact toughness of steel EQ70 for offshore structure. The fracture morphologies were examined by using a scanning electron microscope (SEM, JSM-6480LV), and microstructures etched by 4 vol. % nitric acid were observed on a type 9XB-PC optical microscope. The results show that the impact toughness of steel A is higher than that of steel B at the same test temperature and heat treatment technique. For steel B, the energy absorbed is, in descending order, CQ&T, Q&T and IQ&T, while for steel A, that is CQ&T, IQ&T and Q&T. The effects of heat treatment on the low temperature impact toughness are different for steels A and B, the absorbed energy changes more obviously for steel A. The results can be significant references for actual heat treatment techniques in steel plant.

scholarly journals Microstructure features and formation mechanism in a newly developed electroslag welding

2021 ◽  
Author(s):  
Tomonori Kakizaki ◽  
Shodai Koga ◽  
Hajime Yamamoto ◽  
Yoshiki Mikami ◽  
Kazuhiro Ito ◽  
...  
Keyword(s):  
Low Temperature ◽  
Weld Metal ◽  
Heat Input ◽  
Acicular Ferrite ◽  
Charpy Impact ◽  
Electroslag Welding ◽  
Weld Metals ◽  
Columnar Grains ◽  
Cooling Speed ◽  
Low Temperature Toughness

AbstractElectroslag welding (ESW) is known to show higher heat input than electrogas welding (EGW), resulting in poor low-temperature toughness. However, a newly developed ESW (dev. ESW) method using low-resistivity slag bath exhibited excellent low-temperature toughness as a result of lower effective heat input than conventional EGW, as demonstrated by the faster cooling rates measured in weld metals and estimated using finite element method analyses. This led to much shallower molten pool in the dev. ESW, resulting in much finer columnar grains and thinner centerline axial grains. High cooling speed in the dev. ESW method appeared to contribute to increased acicular ferrite proportion. The uniform microstructure with large acicular ferrite proportion and small number of inclusions in the weld metal permitted the dev. ESW weld metal to possess little variation in Charpy impact energy across the center of weld metal.

scholarly journals EFFECTS OF Q&P PROCESS PARAMETERS ON PROPERTIES OF 42SiCr STEEL

2018 ◽  
Vol 24 (2) ◽  
pp. 126
Author(s):  
Kateřina Rubešová ◽  
Ivan Vorel ◽  
Hana Jirková ◽  
Štěpán Jeníček
Keyword(s):  
Heat Treatment ◽  
Ultimate Strength ◽  
Retained Austenite ◽  
High Strength ◽  
Carbon Diffusion ◽  
Salt Bath ◽  
Treatment Techniques ◽  
Microstructure Effects ◽  
The Impact ◽  
Quenching And Tempering

<p class="AMSmaintext"><span lang="EN-GB">The requirement for high strength and good ductility poses problems in today’s advanced steels. This problem can be tackled by appropriate heat treatment which produces suitable microstructures. By this means, ultimate strengths of about 2000 MPa and elongations of more than 10% can be obtained. One of such advanced heat treatment techniques is the Q&amp;P (Quenching and Partitioning) process. It produces a mixture of martensite and retained austenite, where the latter is an important agent in raising the ductility of steel. </span></p><p class="AMSmaintext"><span lang="EN-GB">In this experiment, a low-alloy steel with 0.41% carbon and manganese, silicon and chromium was used. An air furnace and a salt bath were employed for heat treatment and quenching, respectively. In order to obtain the best ultimate strength and elongation levels, partitioning temperatures of 250°C and 300°C were applied. Partitioning involves carbon diffusion from super-saturated martensite into retained austenite, and tempering of hardening microstructure. Effects of the quenching temperatures of 200°C and 150°C were studied as well. To map the impact of the Q&amp;P process on mechanical properties, an additional schedule with conventional quenching and tempering was carried out. Upon optimization of the parameters, the process produced martensite with a small amount of bainite and retained austenite. The ultimate strength was between 1930 and 2080 MPa and the elongation levels were from 9 to 16%.</span></p><p class="AMSmaintext"><span lang="EN-GB"> </span></p>

Improvement in Toughness of Transportation and Storage Cask Steel for Spent Nuclear Fuel

2007 ◽  
Author(s):  
Hee Kyung Kwon ◽  
Byoung Koo Kim ◽  
Kuk Cheol Kim ◽  
Keun Ho Song ◽  
Jeong Tae Kim
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Radioactive Material ◽  
Low Alloy Steels ◽  
Tempering Temperature ◽  
Impact Properties ◽  
Temperature Impact ◽  
The Impact

Nuclear power plants have been operated for fifty years. Currently the managements of spent fuel are on progress vigorously. Casks for transportation and/or storage of spent nuclear fuel are usually made of SA350 low alloy steels. The wall thickness of the casks are greater than 300mm. But because leakage of nuclear fuel or radioactive material from unexpected brittle fracture is not acceptable, Nil-ductility transition temperatures of colder than −150°F are needed. The effects of chemical composition and heat treatment on low temperature impact properties of SA350 are investigated in this study. The microstructure of SA350 steel is composed of ferrite and pearlite. The variations of microstructure, low temperature impact properties and strength at room temperature with carbon, vanadium and manganese content are analyzed. To improve the low temperature impact properties, heat treatment at an temperature between quenching and tempering temperature is introduced. With the optimum combination of alloying elements and heat treatment, the impact properties can be improved down to the level of nil-ductility transition temperature −150°F.

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