Comparison of two types of low-transformation-temperature weld metals based on solidification mode

Feng, Zhongyuan; Di, Xinjie; Wu, Shipin; Zhang, Zhi; Liu, Xiaoqian; Wang, Dongpo

doi:10.1080/13621718.2017.1376792

Cited by 16 publications

(9 citation statements)

References 27 publications

(29 reference statements)

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“…In particular, the proof that compressive residual stresses are formed [3,4], the investigation of the mechanisms of stress formation [5,6], and the effect on the fatigue strength [7,8] have been the subject of many research projects. Recent publications also deal with extended topics such as microstructure and the associated mechanical properties [9][10][11][12][13], the behaviour during multilayer welding [14][15][16][17][18], and the application of LTT in beam welding [19].…”

Section: Ltt Filler Metalsmentioning

confidence: 99%

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

et al. 2020

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The subject of this study is how, and to what extent, Varestraint/Transvarestraint test results are influenced by both testing parameters and characteristics of evaluation methods. Several different high-alloyed martensitic LTT (low transformation temperature) filler materials, CrNi and CrMn type, were selected for examination due to their rather distinctive solidification cracking behaviour, which aroused interest after previous studies. First, the effects of different process parameter sets on the solidification cracking response were measured using standard approaches. Subsequently, microfocus X-ray computer tomography (μCT) scans were performed on the specimens. The results consistently show sub-surface cracking to significant yet varying extents. Different primary solidification types were found using wavelength dispersive X-ray (WDX) analysis conducted on filler metals with varying Cr/Ni equivalent ratios. This aspect is regarded as the main difference between the CrNiand CrMn-type materials in matters of cracking characteristics. Results show that when it comes to testing of modern highperformance alloys, one set of standard Varestraint testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account.

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Section: Ltt Filler Metalsmentioning

confidence: 99%

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

et al. 2020

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“…It is well-known that tensile welding residual stress is detrimental to the fatigue strength of welded joint [28,29]. To minimize the unfavorable tensile stress, the low transformation temperature (LTT) alloys, which take advantage of martensitic transformation, have been developed during the past two decades [30][31][32]. Furthermore, it has been investigated that an elongated weld method overlaying LTT weld metal on the corner boxing fillet-welded joints can greatly enhance fatigue lives to at least 4 times [33].…”

Section: Thermal Cycles In Elongated Weld With Low Transformation Temmentioning

confidence: 99%

Efficient analysis of welding thermal conduction using the Newton–Raphson method, implicit method, and their combination

Feng

et al. 2020

Int J Adv Manuf Technol

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Finite element analysis is commonly used to investigate the thermal-mechanical phenomena during welding. To improve the computing efficiency of finite element analysis for welding thermal conduction, a novel Newton-Raphson method (NRM) without the computation of inverse matrix and a hybrid method combing the NRM and conventional implicit method (IMP) were developed. Comparison of computing time between the hybrid method implemented in an in-house software JWRIAN and the IMP used in a commercial software ABAQUS indicated that the computing speed of the former was about 4.5 times faster than that of the latter. Additionally, compared to the conventional IMP, the NRM exhibited higher computing efficiency in the analysis of transient thermal conduction during the welding heating process. Meanwhile, a combined hybrid method of the NRM and IMP was verified to be more efficient in analyzing the welding thermal conduction throughout the heating and cooling processes. Moreover, the thermal cycles computed by the hybrid method were consistent with those from experimental measurement, indicating the high accuracy of the hybrid method. Furthermore, the hybrid method was used to predict the temperature field of the corner boxing fillet joint welded by a low transformation temperature weld metal for generation of compressive residual stress.

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“…Secondly, the volume fraction of RA is 7.80% of the LN, while it is 3.26% of the HN. Many researchers [47,48] have reported that the presence of RA is a significant role in improving toughness. During deformation, soft austenite can release internal stress and inhibit crack initiation.…”

Section: Toughness Of Deposited Metalsmentioning

confidence: 99%

The Influence of Ni on Bainite/Martensite Transformation and Mechanical Properties of Deposited Metals Obtained from Metal-Cored Wire

Wang

et al. 2021

Metals

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The multi-pass deposited metals were prepared by metal-cored wire with low (2.5 wt%) and high (4.0 wt%) Ni to research the effect of Ni on the bainite/martensite transformation. Results showed that deposited metals exhibited a multiphase structure comprised of bainite, martensite and residual austenite, which is not only explained from SEM/TEM, but also identified and quantified each phase from crystallographic structure through XRD and EBSD. With Ni content increasing, the fraction of martensite increases from 37% to 41%, and that of bainite decreases from 61% to 55% accordingly because 4% Ni element narrows the temperature range of the bainite transformation ~20 °C. The 7.8% residual austenite exhibited block and sheet in the deposited metal with low Ni, while the fraction of residual austenite was 3.26% as a film with high Ni, caused by different transformation mechanisms of bainite and martensite. The tensile strengths of deposited metals were 1042 ± 10 MPa (2.5% Ni) and 1040 ± 5 MPa (4% Ni), respectively. The yield strength of deposited metals with high Ni was 685 ± 18 MPa, which was higher than low Ni due to the high fraction of martensite. The impact values of deposited metals with high Ni content decreased because the volume fraction of bainite and residual austenite and area fraction of large-angle grain boundary were lower.

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Comparison of two types of low-transformation-temperature weld metals based on solidification mode

Cited by 16 publications

References 27 publications

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

Efficient analysis of welding thermal conduction using the Newton–Raphson method, implicit method, and their combination

The Influence of Ni on Bainite/Martensite Transformation and Mechanical Properties of Deposited Metals Obtained from Metal-Cored Wire

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