The Effect of Material Heterogeneity and Temperature on Impact Toughness and Fracture Resistance of SA-387 Gr. 91 Welded Joints

Jovanović, Milivoje; Čamagić, Ivica; Sedmak, Simon; Sedmak, Aleksandar; Burzić, Zijah

doi:10.3390/ma15051854

Cited by 7 publications

(6 citation statements)

References 13 publications

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“…Titanium alloys exhibit excellent mechanical properties and corrosion resistance, making them a desirable construction material across various industries. The electron beam welding (EBW) process represents one of the methods employed for welding titanium alloys [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Electron Beam Welding Process for Ti6Al-4V Titanium Alloy

Wencel¹,

Wiewiórowska

Wieczorek

et al. 2023

Materials

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The electron beam welding process of titanium alloys induces a series of physicochemical changes in the material that remain a relevant and necessary area of investigation. A necessary step performed after the electron beam welding process of titanium alloys in the Ti6Al-4V grade to mitigate the resulting thermal stresses is the post-weld heat-treatment process conducted through stress relieving. This study presents the comparative analysis results of the mechanical properties and structure of the Ti6Al-4V titanium alloy after electron beam welding and subsequent stress-relieving heat treatment at a temperature of 590 °C for 2 h. The analysis focused on the levels of mechanical properties such as microhardness in the heat-affected zone and weld, tensile strength, and microstructure analysis in the heat-affected zone and weld. The aim of the research was to answer the questions regarding whether the post-weld heat treatment through stress relieving after electron beam welding of the Ti6Al-4V titanium alloy would significantly affect the changes in mechanical properties and microstructure of the alloy and whether the applied welding speed in the study would cause a significant depletion of alloying elements in the material. During the course of the study, it was found that conducting the electron beam welding process at a speed of 8 mm/s resulted in a depletion of one of the alloying elements (aluminum) in the face area. However, the decrease in aluminum content was not significant and did not exceed the critical value of 6% specified in the material standards, which determined the material’s application based on its strength properties.

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Section: Introductionmentioning

confidence: 99%

Electron Beam Welding Process for Ti6Al-4V Titanium Alloy

Wencel¹,

Wiewiórowska

Wieczorek

et al. 2023

Materials

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“…As already mentioned, welded joints are of special interest when toughness is analysed because both the energies for crack initiation and propagation vary significantly in the case of heterogeneous material consisting of base metal (BM), welded metal (WM), and a heat-affected zone (HAZ), including its subzones (coarse grain (CG) and fine grain (FG)) [ 7 , 8 , 9 ]. The ductile–brittle transition is another important aspect of welded joints due to their heterogeneity, as shown by 3D transient analyses of Charpy impact specimens [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…The ductile–brittle transition is another important aspect of welded joints due to their heterogeneity, as shown by 3D transient analyses of Charpy impact specimens [ 10 ]. In the case of two high-temperature steels investigated in [ 8 , 11 , 12 ], detrimental effects of complex welded joint microstructures have been shown. Two steels have been tested—A 387 Gr.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Temperature on S32750 Duplex Steel Welded Joint Impact Toughness

et al. 2023

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The search for alternative materials that can be used for parts of aircraft hydraulic systems has led to the idea of applying S32750 duplex steel for this purpose. This steel is mainly used in the oil and gas, chemical, and food industries. The reasons for this lie in this material’s exceptional welding, mechanical, and corrosion resistance properties. In order to verify this material’s suitability for aircraft engineering applications, it is necessary to investigate its behaviour at various temperatures since aircrafts operate at a wide range of temperatures. For this reason, the effect of temperatures in the range from +20 °C to −80 °C on impact toughness was investigated in the case of S32750 duplex steel and its welded joints. Testing was performed using an instrumented pendulum to obtain force–time and energy–time diagrams, which allowed for more detailed assessment of the effect of testing temperature on total impact energy and its components of crack initiation energy and crack propagation energy. Testing was performed on standard Charpy specimens extracted from base metal (BM), welded metal (WM), and the heat-affected zone (HAZ). The results of these tests indicated high values of both crack initiation and propagation energies at room temperature for all the zones (BM, WM, and HAZ) and sufficient levels of crack propagation and total impact energies above −50 °C. In addition, fractography was conducted through optical microscopy (OM) and scanning electron microscopy (SEM), indicating ductile vs. cleavage fracture surface areas, which corresponded well with the impact toughness values. The results of this research confirm that the use of S32750 duplex steel in the manufacturing of aircraft hydraulic systems has considerable potential, and future work should confirm this.

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“…In general, dissimilar metal-welded joints (DMWJs) in engineering structures are used to connect different metals. Due to strong heterogeneity of the microstructure and mechanical properties at the interface between two metal materials, this part is a weak link of the welded joint, which seriously affects the safety of engineering structures [ 1 , 2 , 3 ] and service life evaluation [ 4 , 5 ]. Therefore, it is of great significance to accurately design the integrity and evaluate the crack at the interface of bi-materials.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Influence of Ultimate-Strength Heterogeneity on Crack Propagation and Fracture Toughness in Welded Joints

Bi¹,

Yuan

Hao³

et al. 2022

Materials

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The mechanical properties of dissimilar metal-welded joint materials are heterogeneous, which is an obstacle to the safety evaluation of key welded structures. The variation of stress–strain conditions at the crack tip caused by mismatch of material mechanical properties in dissimilar metal-welded joints is an important factor affecting crack propagation behavior. To understand the influence of uneven distribution of ultimate strength of the base metal and the welded metal on the crack propagation path, fracture toughness, as well as the mechanical field at the crack tip in the small-scale yield range, the user-defined field variable subroutine method is used to express continuous variation characteristics of welded joint ultimate strength in finite element software. In addition, the J-integral during crack propagation is calculated, and the effect of the ultimate strength on the J-integral and the stress field at the crack tip are analyzed. The results show that as the crack propagation direction is perpendicular to the direction of ultimate strength, the gradient of ultimate strength increases from |Gy|= 50 to |Gy|= 100 MPa/mm, the crack deflection angle increases by 0.018%, and the crack length increases by 1.46%. The fracture toughness of the material decreased slightly during crack propagation. Under the condition that the crack propagation direction is the same as the direction of ultimate strength, the crack propagation path is a straight line. As the gradient of ultimate strength increases from Gx = 50 to Gx = 100 MPa/mm, the crack propagation length decreases by 5.17%, and the slope of fracture toughness curve increases by 51.63%. On the contrary, as the crack propagates to the low ultimate strength side, the crack propagation resistance decreases, the ultimate strength gradient increases from Gx = −100 to Gx = −50 MPa/mm, and the slope of the fracture toughness curve decreases by 51.01%. It is suggested to consider the relationship between crack growth behavior and ultimate strength when designing and evaluating the structural integrity of cracks at the material interface of dissimilar metal-welded joints.

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The Effect of Material Heterogeneity and Temperature on Impact Toughness and Fracture Resistance of SA-387 Gr. 91 Welded Joints

Cited by 7 publications

References 13 publications

Electron Beam Welding Process for Ti6Al-4V Titanium Alloy

Electron Beam Welding Process for Ti6Al-4V Titanium Alloy

Effect of Temperature on S32750 Duplex Steel Welded Joint Impact Toughness

Numerical Investigation of the Influence of Ultimate-Strength Heterogeneity on Crack Propagation and Fracture Toughness in Welded Joints

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