Heat-Affected Zone Toughness of a TMCP Steel Designed for Low-Temperature Applications

1997 ◽  
Vol 119 (2) ◽  
pp. 134-144 ◽  
Author(s):  
J. A. Gianetto ◽  
J. E. M. Braid ◽  
J. T. Bowker ◽  
W. R. Tyson
Keyword(s):  
Low Temperature ◽  
Heat Affected Zone ◽  
Nonmetallic Inclusions ◽  
High Strength ◽  
Opening Displacement ◽  
Initiation Mechanism ◽  
Energy Inputs ◽  
Detailed Evaluation ◽  
Haz Toughness ◽  
Temperature Applications

The objective of this investigation was to provide a detailed evaluation of the heat-affected zone (HAZ) toughness of a high-strength TMCP steel designed for low-temperature applications. The results from both Charpy-vee notch (CVN) and cracktip-opening displacement (CTOD) tests conducted on two straight-walled narrow groove welds, produced at energy inputs of 1.5 and 3.0 kJ/mm, show that significantly lower toughness was exhibited by the grain-coarsened HAZ (GCHAZ) compared with the intercritical HAZ (ICHAZ) region. This is explained based on the overall GCHAZ microstructure, and the initiation mechanism which caused failure. For the particular TMCP steel investigated in this study very good ICHAZ toughness properties were recorded using both HAZ Charpy and CTOD tests. In general, this was attributable to the low hardness, relatively fine ferrite microstructure, and the formation of secondary microphases that were not overly detrimental to the toughness. The lower-bound GCHAZ CTOD results obtained for both welds (KA W-L and KA W-H) did not meet the targeted requirement of δ = 0.07 mm at −50°C. It was found in both welds that low CTOD toughness was associated with the initiation of fracture from nonmetallic inclusions, which were complex oxides containing Ce, La, and S. The sites were located in the subcritical GCHAZ (SCGCHAZ) region in the case of the 1.5 kJ/mm weld and in the GCHAZ for the 3.0 kJ/mm weld. Some variation in CVN toughness was observed at different through-thickness locations. Toughness was lowest for the GCHAZ of the weld deposited at 3.0 kJ/mm and was related to the proportion of GCHAZ being sampled, which was ~55 percent for the bottom compared to 25–30 percent for that of the top location. Recommendations are proposed on the preferred practices and criteria that should be used in establishing guidelines and specifications for evaluating the HAZ toughness of candidate steels for construction of Arctic class ships.

Effects of Ti, C and N on Weld HAZ Toughness of High Strength Line Pipe

2008 ◽  
Author(s):  
Christopher Penniston ◽  
Laurie Collins ◽  
Fathi Hamad
Keyword(s):  
Low Temperature ◽  
Heat Affected Zone ◽  
Construction Projects ◽  
High Strength Steels ◽  
High Strength ◽  
Construction Costs ◽  
Line Pipe ◽  
C And N ◽  
Welding Processes ◽  
Haz Toughness

As pipeline construction projects seek to implement more efficient welding techniques in order to reduce construction costs, it is important to understand the factors that affect the tolerance of the steel to welding processes. This is particularly true in the case of welding high strength steels (X70 and greater) in which increased alloy content will promote the formation of low temperature phases with limited ductility in the heat affected zone (HAZ). In the present study, the effects of titanium (0.008 to 0.015 wt%), nitrogen (60 to 100 ppm) and carbon (0.035 versus 0.060 wt%) have been examined through welds produced by a robotic gas metal arc welder.

Experimental Study on Fracture Toughness of Q460C the High-Strength Construction Steel at Low Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 890-897 ◽  
Author(s):  
Yuan Qing Wang ◽  
Yun Lin ◽  
Yan Nian Zhang ◽  
Yong Jiu Shi
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Function Fitting ◽  
Ductile Brittle Transition Temperature ◽  
Boltzmann Function ◽  
Fracture Appearance ◽  
Crack Tip Opening

Three point bending tests were carried out on 14mm-thick Q460C the high-strength structural steel at low temperature, and scanning electronic microscope of the fracture appearance was analyzed. The results showed that the obvious feature of brittle mechanism was shown on the three point bending specimen fracture whose testing took place at -40°C. And the crack tip opening displacement value of Q460C steel, which was less than that of Q235 steel, Q345 steel and Q390 steel at low temperature, tended to decrease with respect to the temperature reduction. Moreover, a Boltzmann function fitting analysis was applied to the experimental data, and the ductile-brittle transition temperature and the changing regularity were obtained.

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.

Offshore Structural Steel Plates for Extreme Low Temperature Service With Excellent HAZ Toughness

2014 ◽  
Author(s):  
Katsuyuki Ichimiya ◽  
Kazukuni Hase ◽  
Shigeru Endo ◽  
Yusuke Terazawa ◽  
Takaki Fujiwara ◽  
...  
Keyword(s):  
Low Temperature ◽  
Main Property ◽  
Offshore Structures ◽  
Nucleation Site ◽  
Steel Plates ◽  
Crack Tip Opening Displacement ◽  
Offshore Structure ◽  
Opening Displacement ◽  
Low Temperature Toughness ◽  
Haz Toughness

The strength and the toughness required for steel plates used for offshore structures became higher as the installation areas move into arctic areas. The main property of offshore structure steel is the crack tip opening displacement (CTOD) property of weld joint, and CTOD testing is performed at the minimum design temperature of the structure. Thus, the demand for satisfying −40°C of CTOD test temperature specification has increased. For the improvement of HAZ toughness, coarse austenite grain is suppressed by TiN, and low-C, Ceq, Si, P, Nb design is adopted to decrease the formation of M-A constituents. Furthermore, by using Ca inclusion, which works as a pinning particle and a bainite nucleation site, very fine bainite microstructure are formed in HAZ and excellent low temperature toughness are achieved. The YP420 class plate with excellent low temperature toughness has been developed using these technology.

X100 Linepipe With Excellent HAZ Toughness and Deformability

2003 ◽  
Author(s):  
Yoshio Terada ◽  
Hiroshi Tamehiro ◽  
Hiroshi Morimoto ◽  
Takuya Hara ◽  
Eiji Tsuru ◽  
...  
Keyword(s):  
Low Temperature ◽  
Carbon Content ◽  
Heat Affected Zone ◽  
Uniform Elongation ◽  
Base Material ◽  
Controlled Rolling ◽  
Accelerated Cooling ◽  
Low Temperature Toughness ◽  
Sufficient Strength ◽  
Haz Toughness

Good low-temperature toughness of the base material (BM) and weld heat-affected zone (HAZ), and good deformability of the pipe body together with good field weldability are required for X100 linepipe to ensure the safety of pipelines and to facilitate field welding. It is, however, very difficult to attain these properties simultaneously because of the large addition of alloys. The technology of improving HAZ toughness by reducing carbon content through the reduction of M-A constituents harmful to low-temperature toughness was developed, and accelerated cooling after controlled rolling was applied to attain good low-temperature toughness of BM and high uniform elongation together with sufficient strength corresponding to X100. Two newly developed types of X100 linepipe, a “high HAZ toughness type” and a “high uniform elongation type”, exhibited excellent low-temperature toughness of the HAZ and high uniform elongation together with sufficient strength, respectively.

The Properties of Low Yield Ratio and High Heat Input Welding Construction Steel and the Microstructure of HAZ

2014 ◽  
Vol 490-491 ◽  
pp. 69-72
Author(s):  
Dong Ming Duan ◽  
Run Wu ◽  
Meng Xia Tang ◽  
Yong Bu ◽  
Xiao Chen
Keyword(s):  
Low Temperature ◽  
Heat Affected Zone ◽  
Heat Input ◽  
High Strength ◽  
High Heat ◽  
Yield Ratio ◽  
Construction Steel ◽  
High Heat Input ◽  
Electron Microscopes ◽  
Fine Pearlite

Steel with low yield ratio (YR0.75) and high heat input welding was made by combining Zr, Ti microalloying. Its microstructure investigated by optical and electron microscopes (SEM, TEM), consists of ferrite with the fine pearlite which not only ensures the high strength and toughness but also decreases the yield ratio. The steel was simulated in 100 kJ/cm heat input welding. The microstructures for heat affected zone (HAZ) of weldments mainly consisted of acicular ferrites which nucleate on fine Zr and Ti contained inclusions. The acicular ferrites decrease detrimental influence of grain coursing in the HAZ and make the steel good toughness in low temperature.

COPPER ALLOY No. 510

Alloy Digest ◽  
1971 ◽  
Vol 20 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Fatigue Properties ◽  
Temperature Performance ◽  
Tin Bronze

Abstract COPPER ALLOY No. 510 is a tin bronze containing about 0.25% phosphorus. It combines high strength and toughness with excellent fatigue properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-238. Producer or source: Brass mills.

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