Structure and properties of the heat-affected zone of low-alloyed cold-resistant steel for arctic application

2019 ◽  
pp. 30-51 ◽  
Author(s):  
O. V. Sych ◽  
E. I. Khlusova ◽  
U. A. Pazilova ◽  
E. A. Yashina
Keyword(s):  
Yield Strength ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Heating Temperature ◽  
Resistant Steel ◽  
Structure And Properties ◽  
Before And After ◽  
Comprehensive Study

The paper presents the results of a comprehensive study of structural and properties changes in the most dangerous regions of the heat-affected zone of low-alloyed cold-resistant steel with a guaranteed yield strength of 355–390 MPa before and after the post-welding tempering, including when the heating temperature is subjected to tempering and deformation, comparing with the base metal. The simulation was performed on the dilatometer DIL 805 and the GLEEBLE 3800 complex. The results of the investigation of the structure and properties of real welded joints after welding with different linear energy (3.5 and 6 kJ/mm) are presented.

FE Simulation of Cold Cracking Susceptibility in X70 Structural Steel Welded Joints

2011 ◽  
Author(s):  
Vigdis Olden ◽  
Odd Magne Akselsen
Keyword(s):  
Hydrogen Embrittlement ◽  
Yield Strength ◽  
Structural Steel ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Fe Simulation ◽  
Coarse Grained ◽  
Best Fitting ◽  
Low Sensitivity

Fracture mechanics SENT testing and FE simulation to establish hydrogen influenced cohesive parameters for X70 structural steel welded joints have been performed. Base metal and weld simulated coarse grained heat affected zone have been included in the study. The base metal did not fail at net section stresses lower than 1.29 times the yield strength and reveals low sensitivity to hydrogen embrittlement. The weld simulated coarse grained heat affected zone was prone to fracture at stresses above 64% of the yield strength, which indicates hydrogen embrittlement susceptibility. The cohesive parameters best fitting the experiments are δc = 0.3 mm and σc = 1700 MPa (3.5·σy) for the base metal and δc = 0.3 mm and σc = 2100 MPa (2.6·σy) for the coarse grained heat affected zone.

Effect of Nd on Structure and Properties of Hypereutectic Al-Si Alloys

2012 ◽  
Vol 476-478 ◽  
pp. 105-108
Author(s):  
Bo Gao ◽  
Fei Jiang ◽  
Yi Hao ◽  
Gan Feng Tu ◽  
Lei Chen ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Wear Resistance ◽  
Yield Strength ◽  
Structure And Properties ◽  
Initial Sample ◽  
Primary Si ◽  
Before And After ◽  
Average Size

The influence of Nd on structure and properties of hypereutectic Al-Si alloys (Al-17.5%Si, Al-25%Si) was investigated in this paper. For Al-17.5%Si alloy, there is no obvious variation in morphology of primary Si before and after Nd modification, but the average size of primary Si is decreased from 34.73µm to 23.39µm after 0.3%Nd modification. Compared with initial sample, the tensile strength and yield strength of 0.3%Nd-modified sample are increased by 11.6% and 1.5%, and wear resistance of Al-17.5%Si alloy is enhanced to a factor of 2.1 after 0.3%Nd modification. However, for Al-25%Si alloy, the tensile strength and yield strength of 0.3%Nd-modified sample are respectively improved by 22.1% and 9.5% as compared to initial sample. Meanwhile, wear resistance of modified sample is improved to a factor of 3 relative to initial sample. The property improvement of two alloys can be attributed to the change in morphology and size of primary Si after Nd modification.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

Temper Embrittlement Analyses at HAZ in New Generation of 2-1/4Cr-1Mo Steels by CTOD Tests

Materials ◽  
2003 ◽  
Author(s):  
Petronio Zumpano ◽  
Itamar Ferreira
Keyword(s):  
Fracture Toughness ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Room Temperature ◽  
Microstructural Analysis ◽  
Temper Embrittlement ◽  
Fine Grain ◽  
Before And After ◽  
Electron Microscope Analysis ◽  
New Generation

Temper embrittlement susceptibility was analyzed at HAZ of welded joints at room temperature in new generation of 2-1/4Cr-1Mo steels. Assessment was made by fracture toughness parameter CTODm in welded joints at coarse-grain heat affected zone (CGHAZ) and fine-grain heat affected zone (FGHAZ). Microstructural analysis was made before and after CTODm tests to place correctly fatigue pre crack at CGHAZ or at FGHAZ. Temper embrittlement simulation was made by “Step Cooling” treatment. Hardness results and microstructural analysis proved the use of stress associated with “Step Cooling” made the efficacy of this treatment better. The control of impurities content in the steel avoids development of temper embrittlement. This was confirmed by fracture toughness experiments at room temperature. No significant variation on CTODm results of three different situations of treatment and between CGHAZ and FGHAZ were observed. Scanning Electron Microscope analysis indicated fracture mechanism after embrittlement simulation was microvoids coalescence.

Evaluation of Creep Strength Reduction Factors for Welded Joints of Grade 122 Steel

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Yukio Takahashi ◽  
Masaaki Tabuchi
Keyword(s):  
Base Metal ◽  
Creep Strength ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Thermal Power ◽  
Strength Reduction ◽  
Creep Rupture ◽  
Piping System ◽  
Type Iv ◽  
Rupture Data

HCM12A (ASME Grade 122) is used for boiler components in thermal power plants because of its high creep strength. However, a type IV creep damage formed in the heat-affected zone can cause a considerable decrease in the creep strength of the weldment and a failure of large diameter piping due to this damage took place recently in a thermal power plant. In order to update the design method and develop life estimation method for this kind of piping system with axial weld, the creep rupture data of base metal and welded joints have been collected and analyzed by the Strength of High-Chromium Steel Committee in Japan. In the present paper, the creep rupture data of over 400 points for welded joint specimens of HCM12A offered from six Japanese organizations are analyzed. These data clearly indicate that the long-term creep strength of the welded joints becomes weaker than that of the base metal at above 600°C due to the type IV fracture in the fine grain heat-affected zone. After the discussions on the effects of product form, welding procedure, specimen sampling procedure, etc., on the creep strength, the master creep life equation for the welded joints is developed. The so-called region decomposition technique was adopted to fit the data in both high and low stress regimes with a reasonable accuracy. The creep strength reduction factor obtained from 100,000 h creep strength of the welded joints and the base metal is given as a function of temperature.

scholarly journals Study on impact properties of creep-resistant steel thermally simulated heat affected zone

2012 ◽  
Vol 16 (2) ◽  
pp. 513-525 ◽  
Author(s):  
Radivoje Mitrovic ◽  
Dejan Momcilovic ◽  
Olivera Eric ◽  
Ivana Atanasovska ◽  
Nenad Hut
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Power Plants ◽  
Operating Temperature ◽  
Resistant Steel ◽  
Pipe Line ◽  
Coal Power Plants ◽  
Steam Pipe ◽  
Critical Zones

The steam pipe line (SPL) and steam line material, along with its welded joints, subject to damage that accumulates during operation in coal power plants. As a result of thermal fatigue, dilatation of SPL at an operating temperature may lead to cracks initiation at the critical zones within heat affected zone (HAZ) of steam pipe line welded joints. By registration of thermal cycle during welding and subsequent HAZ simulation is possible to obtain target microstructure. For the simulation is chosen heat resisting steel, 12H1MF (designation 13CrMo44 according to DIN standard). From the viewpoint of mechanical properties, special attention is on impact toughness mostly because very small number of available references. After simulation of single run and multi run welding test on instrumented Charpy pendulum. Metallographic and fractographic analysis is also performed, on simulated 12H1MF steel from service and new, unused steel. The results and correlation between microstructure and impact toughness is discussed, too.

Optimization of the structure and properties of the heat-affected zone of welded joints in high-strength pipe steels

2015 ◽  
Vol 29 (9) ◽  
pp. 712-717 ◽  
Author(s):  
A.A. Velichko ◽  
V.V. Orlov ◽  
U.A. Pazilova ◽  
R.V. Sulyaguin ◽  
E.I. Khlusova
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
High Strength ◽  
Structure And Properties ◽  
Pipe Steels
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