Influence of microstructural aspects on impact toughness of multi-pass submerged arc welded HSLA steel joints

Lan, Liangyun; Kong, Xiangwei; Qiu, Chunlin; Zhao, Dewen

doi:10.1016/j.matdes.2015.10.158

Cited by 120 publications

(46 citation statements)

References 29 publications

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“…As the microstructure determines the mechanical properties of the steel, it is important to minimize the negative effects the thermocycle has on the microstructure. The HAZ tends to have larger grain size due to the grain growth caused by elevated temperatures, which, along with carbides and other microstructural changes, is detrimental to the mechanical properties of the weld [7][8][9][10][11][12]. The HAZ comprises several subzones: the coarse-grained HAZ (CGHAZ), the fine-grained HAZ (FGHAZ), the intercritical HAZ (ICHAZ), the subcritical HAZ (SCHAZ) and, in the case of multipass welds, the intercritically reheated CGHAZ (ICCGHAZ) [7].…”

Section: Introductionmentioning

confidence: 99%

Effect of enhanced cooling on mechanical properties of a multipass welded martensitic steel

Laitila

Larkiola

2019

Weld World

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The effect of forced cooling using heat sinks on the mechanical properties and interpass waiting time of two-pass welds has been studied for a martensitic steel with a yield strength of 960 MPa when the interpass temperature was 100°C. Cross-weld tensile and − 40°C Charpy-V impact toughness properties were examined. The use of heat sinks is shown to result in a beneficial increase of the cross-weld yield strength but at the expense of the yield-to-tensile strength ratio. Due to its particularly detrimental effect on the heat-affected zone (HAZ) toughness of multipass welds, special attention was given in the Charpy-V toughness of the intercritically reheated coarse-grained HAZ (ICCGHAZ) by also testing simulated ICCGHAZs. It is shown that forced cooling has a beneficial effect in respect of the toughness of this simulated subzone and on the Charpy-V toughness of the HAZ of the actual welds. The interpass cooling time during the two-pass welding was reduced by 37%. The results indicate that, in the case of high-strength steels, it may be possible to simultaneously improve both welding productivity and mechanical properties by using forced cooling down to 100°C to reduce waiting time between weld passes.

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Section: Introductionmentioning

confidence: 99%

Effect of enhanced cooling on mechanical properties of a multipass welded martensitic steel

Laitila

Larkiola

2019

Weld World

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“…This demonstrates that increasing grain size accelerates both the initiation and propagation of cleavage cracks and consequently reduces the impact toughness. Additionally, the acicular ferrite can effectively improve the impact toughness of the weld metal, while the coarse granular bainite is inclined to induce the nucleation of cracks [14]. The interlocking nature of fine acicular ferrites can restrain the cleavage crack propagation in the low alloy steels.…”

Section: Charpy Impact Toughnessmentioning

confidence: 99%

Microstructure and mechanical property of 738 low alloy steel welded joint

Xie

Sun

2019

Heat Treatment and Surface Engineering

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This paper aims to investigate the microstructure, microhardness and impact toughness of the gas-tungsten arc welding (GTAW) 738 low alloy steel joint before and after post-weld heat treatment (PWHT). The microstructure of the weld metal of the as-welded (AW) joint consists of acicular ferrite, bainite and martensite-austenite (M-A) constituents. The fraction of each phase in the weld metal of AW joint and PWHT joint was quantitatively measured by Mössbauer spectroscopy. The grain size of the weld metal obviously increases and M-A constituents decompose after PWHT. The carbides precipitate along ferrite boundaries and inside ferrite grains. The microhardness of the weld metal and heat affected zone (HAZ) obviously decreases after PWHT. PWHT promotes the grain growth and the carbide precipitation, which results in a lower impact toughness for the PWHT joint compared with the AW joint.

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“…However, gas metal arc welding and other modern welding techniques require the use of a suitable filler material. Although it was shown that undermatching welding consumables can be sufficient for some welding processes and conditions [1][2][3], a new generation of welding consumables with a higher strength level is desirable, while keeping the toughness above 47 J at -20°C.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and mechanical properties of high-strength steel welding consumables with a minimum yield strength of 1100 MPa

et al. 2018

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Welded high-strength steel components have great potential for use in lightweight constructions or highly loaded structures. Welding of steels with a yield strength of more than 1100 MPa is particularly challenging because of the toughness requirements for the weld metal. Currently, a new generation of welding consumables with a minimum yield strength of 1100 MPa has been developed. Based on electron backscatter diffraction and atom probe tomography, a concept for toughening and strengthening of all-weld metal samples was deployed. Starting from a martensitic all-weld metal sample with an approximate yield strength of 1000 MPa, a reduction in manganese and silicon content resulted in a refined microstructure with a lower prior austenite grain size and effective grain size. Furthermore, a higher average grain boundary misorientation was measured, which influences the toughness positively. An addition of vanadium caused the formation of vanadium-rich clusters, which increased the strength of the all-weld metal significantly. With a combination of these two mechanisms, it was possible to produce an all-weld metal sample with the required yield strength of more than 1100 MPa and an acceptable toughness.

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Influence of microstructural aspects on impact toughness of multi-pass submerged arc welded HSLA steel joints

Cited by 120 publications

References 29 publications

Effect of enhanced cooling on mechanical properties of a multipass welded martensitic steel

Effect of enhanced cooling on mechanical properties of a multipass welded martensitic steel

Microstructure and mechanical property of 738 low alloy steel welded joint

Microstructure and mechanical properties of high-strength steel welding consumables with a minimum yield strength of 1100 MPa

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