Microstructure and Properties of Weld CGHAZ under Different Heat Input for X90 Pipeline Steel

2016 ◽  
Vol 850 ◽  
pp. 943-949
Author(s):  
Liu Qing Yang ◽  
Yong Li Sui ◽  
Pei Pei Xia ◽  
Hai Hong Zhao ◽  
Zhang Hua Yin
Keyword(s):  
Impact Toughness ◽  
Impact Energy ◽  
Heat Input ◽  
Pipeline Steel ◽  
Charpy Impact ◽  
Optical Microscope ◽  
Granular Bainite ◽  
Alloy Content ◽  
Low Temperature Impact Toughness ◽  
The Impact

Two kinds of industry trial X90 pipeline steels which have different chemical composition were chosen as test objects, and the grain coarsening, microstructural characteristics and the variation rules of low-temperature impact toughness in weld CGHAZ of this two steel under different welding heat input were studied by physical thermal simulation technology, SEM, optical microscope and Charpy impact tests. The results showed that the microstructure in weld CGHAZ of 1# steel was mainly bainite ferrite (BF) and most of the M/A constituents were blocky or short rod-like; the grains of 2# steel were coarse and there was much granular bainite (GB). Meanwhile M/A constituents became coarser and their morphology changed from block to long bar; alloy content of X90 pipeline steel under different weld heat input had great effect on the grain size of original austenite. When heat input was lower than 20KJ/cm, the impact toughness in CGHAZ of lower alloy content pipeline steel was good; as heat input increased, impact toughness in CGHAZ of 1# steel increased to the values between 260J and 300J when heat input was between 20KJ/cm and 25KJ/cm and the dispersion of impact energy was small. The impact toughness of 2# steel decreased gradually and the impact energy had the obvious dispersion.

Microstructure and Toughness of Weld CGHAZ Under Different Heat Input for X90 High Strength Pipeline Steel

2016 ◽  
Author(s):  
Liuqing Yang ◽  
Yongli Sui ◽  
PeiPei Xia ◽  
Die Yang ◽  
Yongqing Zhang
Keyword(s):  
Impact Toughness ◽  
Impact Energy ◽  
Heat Input ◽  
Pipeline Steel ◽  
Charpy Impact ◽  
Optical Microscope ◽  
Granular Bainite ◽  
Alloy Content ◽  
Welding Heat Input ◽  
The Impact

Two kinds of industry trial X90 pipeline steel which had different chemical composition were chosen as experimental materials, and the grain coarsening, microstructure evolution characteristics and the variation rules of low-temperature impact toughness in weld CGHAZ of this two steel under different welding heat input were studied by physical thermal simulation technology, SEM, optical microscope and Charpy impact test. The results show that microstructure in weld CGHAZ of 1# steel is mainly bainite ferrite (BF) and most of the M/A constituents are blocky or short rod-like; the grains of 2# steel are coarse and there is much granular bainite (GB), meanwhile M/A constituents become coarse and their morphology is changing from block to elongated laths; alloy content of X90 pipeline steel under different welding heat input has great effect on the grain size of original austenite, and when heat input is lower than 2.0KJ/mm, Charpy impact toughness in CGHAZ of lower alloy content pipeline steel is good; as heat input increases, impact toughness in CGHAZ of 1# steel is on the rise, and it is high (between 260J and 300J) when heat input is between 2.0KJ/mm and 2.5KJ/mm and the scatter of impact energy is small; impact toughness of 2# steel decreases gradually and the impact energy has obvious variability.

Effect of Trace Boron on Low Temperature Impact Toughness of Hot-Rolled Nb-Added HSLA H-Beams

2012 ◽  
Vol 174-177 ◽  
pp. 1030-1033 ◽  
Author(s):  
Guo Tao Cui ◽  
Zuo Cheng Wang ◽  
Tao Sun ◽  
Wei Min Guo ◽  
Jun Qing Gao
Keyword(s):  
Impact Toughness ◽  
Impact Energy ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Total Oxygen ◽  
Transmission Electron ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness ◽  
Hot Rolled ◽  
The Impact

In this research, trace boron (4ppm, 8ppm, 11ppm) was added into the Nb-added HSLA H-beams. The impact toughness of H-beams with/without boron was examined by Charpy impact test (V-notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results prove that the absorbed impact energy at -40°C for the 4ppm, 8ppm, 11ppm boron-added steels respectively reaches up to 80J, 126J, 85J from 15J and H-beams with boron have a lower FATT than that without boron. It is also found that the total oxygen content affects the absorbed impact energy to a certain extent. It is discovered by transmission electron microscope (TEM) that boron mainly exists in solid solution state, except that a little amount of Fe23(C, B)6is formed at the grain boundaries, and the distribution of Nb(C, N) is also influenced by boron addition.

Effect of Welding Processes with High Heat Input on the Microstructure and Toughness of Coarse-Grained Heat-Affected Zone of a High-Strength High-Toughness Steel

2018 ◽  
Vol 937 ◽  
pp. 61-67
Author(s):  
Yu Jie Li ◽  
Jin Wei Lei ◽  
Xuan Wei Lei ◽  
Oleksandr Hress ◽  
Kai Ming Wu
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Heat Input ◽  
High Strength ◽  
High Heat ◽  
Coarse Grained ◽  
Low Temperature Impact Toughness ◽  
The Impact ◽  
Welding Processes

Utilizing submerged arc welding under heat input 50 kJ/cm on 60 mm thick marine engineering structure plate F550, the effect of preheating and post welding heat treatment on the microstructure and impact toughness of coarse-grained heat-affected zone (CGHAZ) has been investigated. The original microstructure of the steel plate is tempered martensite. The yield and tensile strength is 610 and 660 MPa, respectively. The impact absorbed energy at low temperature (-60 °C) at transverse direction reaches about 230~270 J. Welding results show that the preheating at 100 °C did not have obvious influence on the microstructure and toughness; whereas the tempering at 600 °C for 2.5 h after welding could significantly reduce the amount of M-A components in the coarse-grained heat-affected zone and thus improved the low temperature impact toughness.

Impact Toughness Characteristics of SM570-TMC Steel Joint Using Welding Wire Containing 0.4% Nickel at Different Level of Heat Input

2020 ◽  
Vol 867 ◽  
pp. 117-124
Author(s):  
Herry Oktadinata ◽  
Winarto Winarto ◽  
Dedi Priadi ◽  
Eddy S. Siradj ◽  
Ario S. Baskoro
Keyword(s):  
Impact Toughness ◽  
Heat Input ◽  
High Heat ◽  
Optical Microscope ◽  
Butt Joint ◽  
Welding Wire ◽  
Steel Joint ◽  
Microstructure Observation ◽  
High Heat Input ◽  
The Impact

The study was conducted to evaluate the impact toughness of flux-cored arc welded of SM570-TMC steel joint under different heat inputs, 0.9 kJ/mm (low heat input) and 1.6 kJ/mm (high heat input). Welding wire containing 0.4%Ni was selected on this experiment. Multi-pass welds were performed on SM570-TMC steel plate of 16 mm in thickness with a single V-groove butt joint on flat position (1G). The evaluation consists of observations on microstructure using an optical microscope and SEM-EDS, and mechanical properties including tensile, microhardness Vickers and Charpy V-notch (CVN) impact test at temperatures of 25, 0 and-20 °C. Results showed that the impact toughness of the base metal (BM) was higher than the weld metal (WM) at all test temperatures. Hardness and impact toughness of WM at low heat input was observed higher than when applied a high heat input. The welded samples at low and high heat inputs had high of tensile strength, and the fracture seemly occurs on the BM. Microstructure observation showed that at a high heat input, larger grains and microsegregation were observed. It might affect on decreasing their impact property.

Effects of Zirconium on Impact Toughness for the Hull Structure Steel Plate

2014 ◽  
Vol 644-650 ◽  
pp. 4932-4935
Author(s):  
Tie Li Qi
Keyword(s):  
Impact Toughness ◽  
Impact Energy ◽  
Heat Input ◽  
Steel Plate ◽  
Sharp Decline ◽  
Large Size ◽  
Welding Heat Input ◽  
Hull Structure ◽  
Large Heat ◽  
The Impact

The Gleeble3500 combined with SEM, TEM and other experimental methods are employed in this paper to investigate the effects of zirconium content on impact toughness of heat affected zone (HAZ) of hull structure steel plate during the large heat input welding. The results showed when 0.01% zirconium were added in the steel, the impact energy reached 224 J at-60°C experienced 150 kJ/cm welding heat input. But the large-size rectangular inclusions are found in CGHAZ when 0.02% zirconium were added in the steel, the impact energy fell to 38 J at-60°C experienced 150 kJ/cm welding heat input, the large-size inclusions, especially rectangular inclusion, were the main cause for the sharp decline of low temperature toughness after welding.

EFFECT OF BORON ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HOT-ROLLED Nb-ADDED HSLA H-SECTION STEEL

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1885-1890 ◽  
Author(s):  
ZUOCHENG WANG ◽  
GUOTAO CUI ◽  
TAO SUN ◽  
WEIMIN GUO ◽  
XIULING ZHAO ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Charpy Impact ◽  
High Strength ◽  
Charpy Impact Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Boron Addition ◽  
Low Temperature Impact Toughness ◽  
The Impact

In our research, boron was added into the Nb -added high strength low alloy (HSLA) H -section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H -section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test ( V -notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

scholarly journals Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process

2017 ◽  
Vol 62 (2) ◽  
pp. 1341-1346 ◽  
Author(s):  
K.-A. Lee ◽  
Y.-K. Kim ◽  
J.-H. Yu ◽  
S.-H. Park ◽  
M.-C. Kim
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Selective Laser Melting ◽  
Impact Energy ◽  
Charpy Impact ◽  
Melting Process ◽  
Laser Melting ◽  
Average Impact ◽  
Before And After ◽  
The Impact

AbstractThis study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-βgrain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment,αandβphase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.

Impact Toughness of 0.3 Mass% Carbon Tempered Martensitic Steels Evaluated by Instrumented Charpy Test

2014 ◽  
Vol 783-786 ◽  
pp. 1033-1038
Author(s):  
Shigeto Takebayashi ◽  
Kohsaku Ushioda ◽  
Naoki Yoshinaga ◽  
Shigenobu Ogata
Keyword(s):  
Impact Toughness ◽  
Temperature Dependence ◽  
Impact Energy ◽  
Charpy Impact ◽  
Waveform Analysis ◽  
Charpy Impact Energy ◽  
Martensitic Steels ◽  
Tempering Temperature ◽  
Wide Range ◽  
The Impact

The effect of tempering temperature on the impact toughness of 0.3 mass% carbon martensitic steels with prior austenite grain (PAG) size of about 6 μm and 30 μm were investigated. Instrumented Charpy impact test (ICIT) method was used to evaluate the impact toughness. The tempering temperature of 723K gives the largest difference in the Charpy impact energy at room temperature (RT) between the specimens with two different PAG sizes. Investigation of the test temperature dependence of Charpy impact energy in the 723K tempered steels shows a steep transition at around 200 K for the 6 μm PAG specimen, while it shows a continuous slow transition in a wide range of temperature for the 60 μm PAG specimen. ICIT waveform analysis shows that the fracture propagation energy in stead of the fracture initiation energy mainly controls the temperature dependence of the impact energy. The carbide size distribution in these two specimens was investigated by SEM and TEM. The 60 μm PAG specimen shows the distribution of coarser carbides than does the 6 μm PAG specimen, which seems to be the main reason for the observed difference between them in the Charpy impact energy and the other properties of impact fracture.

Bending and Tempering Process of L415M Hot Induction Bend Used in Low Temperatures Areas

2016 ◽  
Vol 850 ◽  
pp. 910-915
Author(s):  
Li Jun Yan ◽  
Yu Zhuo Li ◽  
Peng Zhu ◽  
Jia Shi ◽  
Jin Sheng Liu ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Process Parameters ◽  
Impact Energy ◽  
Water Quenching ◽  
Granular Bainite ◽  
Temper Brittleness ◽  
Column Structure ◽  
Tempering Treatment ◽  
The Impact ◽  
Tempering Process

Test bends of L415M hot induction bend of 508 mm OD×14.3 mm WT used in –45°C areas were conducted. The bending and tempering process parameters were designed, the influences of bending and tempering process parameters on impact toughness at –45°C and microstructure of tangent weld and bend weld were investigated. Hot induction bend was produced by the process of local induction heating+fast water quenching. After tempering treatment, the weld contained martensite-austenite (M-A) islands, carbide precipitations, welded column crystal structure and little pearlite (P), and the brittle fracture surface contained S segregation, the temper brittleness of the weld occurred, which lead to impact energy of bend weld to be lower than 40 J at –45°C. Without post-bending tempering treatment, the microstructures of bend weld was a composite of polygonal ferrite (PF) and granular bainite (GB) with small size and uniform distribution, the coarse column structure and acicular ferrite (AF) disappeared in the weld, so the impact energy of bend weld was higher than 70 J at –45°C, but the impact energy of tangent weld was very poor. It suggests that the process of overall induction of heating + fast water quenching + no tempering treatment is more reasonable, the process ensures that the impact toughness at –45°C, strength and other properties of bend meet the requirements of CDP-S-OGP-PL-016-2011-2.

Effect of Heat Input on Impact Toughness of Coarse-Grained Heat-Affected Zone of a Nb-Ti Microalloyed Pipeline Steel

2012 ◽  
Vol 538-541 ◽  
pp. 2026-2031 ◽  
Author(s):  
Zhou Gao ◽  
Ran Wei ◽  
Kai Ming Wu
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Pipeline Steel ◽  
High Heat ◽  
Coarse Grained ◽  
Bainitic Microstructure ◽  
Homogenous Distribution ◽  
High Heat Input ◽  
The Impact

The effect of varying heat inputs (20, 100, 200 kJ/cm) on the microstructures and toughness of the simulated coarse-grained heat-affected zone of a Nb-Ti microalloyed pipeline steel were investigated utilizing optical and electron microscope. Results showed that the impact toughness of the coarse-grained heat-affected zone maintained a higher level at the heat input of 20 and 100 kJ/cm, whereas it dropped to a much lower level at the heat input of 200 kJ/cm. The good toughness was attributed to the grain refinement and the homogenous distribution of fine and elongated martensite/austenite constituents. The deterioration of toughness for high heat input simulated welding was mainly caused by the coarse bainitic microstructure and massive martensite/austenite constituents.

Sign in / Sign up

Export Citation Format

Share Document