Use of Martensitic Stainless Steel Welding Consumable to Substantially Improve the Fatigue Strength of Low Alloy Steel Welded Structures

Scandella, Fabrice; Cavallin, Nicolas; Gressel, Philippe; Haouas, Jessy; Jubin, Laurent; Lefèbvre, Fabien; Huther, I.

doi:10.1016/j.proeng.2013.12.067

Cited by 2 publications

(2 citation statements)

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“…When a martensitic steel piece is to be welded, the heated steel contains higher levels of alloying elements. The calculation of the martensite starts temperature (Ms) based on Andrew's empirical formula is not appropriate [15]. Another equation recommended for determining the Ms temperature of martensitic creep-resistant steels is as follows (concentrations are in wt-%) […”

Section: Experimental Methodsmentioning

confidence: 99%

Preheating Temperature Effect on Crystal Structure and Texture of Martensitic Stainless Steel

Priyanto

Muslih

Mugirahardjo

et al. 2018

MST

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Theoretically, the preheating temperature refers to the start martensite temperature (Ms), and the martensite transformation can be considered as the conservation of the invariant habit-plane in the lattice structure. The habit-plane is the interface plane between austenite and martensite as measured on a macroscopic scale. From the calculation, Ms = 252 °C. The martensite formation can be affected by temperature or stress treatment. In this experiment, temperature treatment was conducted. The sample was treated at 250 °C ± 10 °C. Before and after the pre-heat treatment, the sample was characterized using the neutron diffraction method. BATAN's Texture Diffractometer (DN2) with a neutron wavelength of 1.2799Å was used to characterize the sample. Analysis of the crystal structure showed that there are three phases before the preheating. The lattice parameters (a) obtained were as follows: for the -phase, a = 2.8501 ± 0.0004 Å; for the α'phase, a= b =2.517 ± 0.003 Å, and c= 3.581 ± 0.002 Å; for the -phase, a= 3.5884 ± 0.0004 Å, Rwp = 17.94%, and  = 1.33. After preheating, only the -phase appears with a = 3.5830 ± 0.0005 Å, Rwp = 26.03%, and  = 1.17. The orientation distribution function is modeled by the sample symmetrization model based on triclinic to orthorhombic sample symmetry. It shows that, before being preheated, the -phase has {100} <001> with texture index (F 2 ) between 0.701 m.r.d. to 3.650 m.r.d., the α-phase has a texture index between 0.923 m.r.d. to 1.768 m.r.d., and the '-phase has a texture index between 0.910 m.r.d. to 1.949 m.r.d. After being preheated, the -phase also has {100} <001> with a texture index between 0.846 m.r.d. to 3.706 m.r.d. It can be concluded, that because of the high preheating temperature, a phase change from martensite to austenite occurred that allowed the sample to be welded easily. After preheating, the -phase has the same cubic type orientation {100} <001>, and the texture index is nearly the same as that before preheating, with not martensite present. AbstrakPengaruh Suhu Pemanasan-Awal pada Struktur Kristal dan Tekstur Baja Tahan Karat Martensitik. Secara teoritis, suhu pemanasan awal mengacu pada suhu martensit awal (Ms), dan transformasi martensit dapat dianggap sebagai konservasi dari habit-plane invarian dalam struktur kisi. Habit-plane adalah bidang antarmuka antara austenit dan martensit yang diukur pada skala makroskopik. Dari perhitungan, Ms = 252 °C. Pembentukan martensit dapat dipengaruhi oleh suhu atau perlakuan tekanan. Dalam percobaan ini, perlakuan suhu dilakukan. Sampel diperlakukan pada 250 °C ± 10 °C. Sebelum dan sesudah perlakuan pemanasan-awal, sampel dikarakterisasi menggunakan metode difraksi neutron. Difraktometer Tekstur BATAN (DN2) dengan panjang gelombang neutron 1,2799 Å digunakan untuk mengkarakterisasi sampel. Analisis struktur kristal menunjukkan bahwa ada tiga fase sebelum pemanasan awal. Parameter kisi (a) yang diperoleh adalah sebagai berikut: untuk fasa-α, a = 2,8501 ± 0,0004 Å; untuk fasa-α', a = b = 2,517 ± 0,003 Å, dan c = ...

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Section: Experimental Methodsmentioning

confidence: 99%

Preheating Temperature Effect on Crystal Structure and Texture of Martensitic Stainless Steel

Priyanto

Muslih

Mugirahardjo

et al. 2018

MST

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“…Fatigue tests showed that the LTT joint had a 40% increase in fatigue strength compared to conventional joints. Fabrice et al [14] found that the LTT wire significantly improved the fatigue strength of the joint, and the fatigue strength was 60% higher than that of the conventional wire (G3Si1) filling joint in two million cycles. Wang et al[15] compared the conventional wire of C-Mn and LTT wire of 9.1 Cr-8.5 Ni-1.25 Mn, and showed that the fatigue strength was improved by 59% when using LTT wire.…”

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The Effect of Martensitic Phase Transformation Dilation on Microstructure, Strain–Stress and Mechanical Properties for Welding of High-Strength Steel

et al. 2018

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The application of low transformation temperature (LTT) wire can effectively reduce residual stress, without the need for preheating before welding and heat treatment after welding. The mechanism reduces the martensitic transformation temperature, allowing the martensite volume expansion to offset some or all of the heat-shrinking, resulting in reduced residual stress during the welding process. In this paper, commercial ER110S-G welding wire and LTT wire with chemical composition Cr10Ni8MnMoCuTiVB were developed to solve the problem of stress concentration. The microstructure of the LTT joint is mainly composed of martensite and a small amount of residual austenite, while the microstructure of the ER110S-G joint is mainly composed of ferrite and a small amount of granular bainite. The micro-hardness and tensile strength of the LTT joint is higher than that of ER110S-G joint; however, the impact toughness of the LTT joint is not as good as that of the ER110S-G joint. The martensitic phase transformation of LTT starts at 212 • C and finishes at around 50 • C, and the expansion caused by phase transition is about 0.48%, which is much higher than that of the base metal (0.15%) and ER110S-G (0.18%). The residual tensile stress at the weld zone of the ER110S-G joint is 175.5 MPa, while the residual compressive stress at the weld zone of LTT joint is −257.6 MPa.2 of 15 reduced tensile residual stress during welding process. This not only reduces the production cost, but also improves the fatigue resistance of the welded components [9].Dai et al.[10] used the traditional commercial OK75.78 wire and the low transformation temperature (LTT) wire to weld two comparable Weldox960 base plates. The residual stress of the joints were measured using neutron diffraction, with the results showing that LTT can effectively reduce the welding residual stress of high-strength steel welding and improve the stress distribution. Chiaki and Shiga [11] found that the residual stress distribution is ideal when the starting temperature of martensite transformation is 200 • C, and the residual compressive stress at the weld toe is 300 MPa.Ohta et al. [12] found that by using the 10 Cr-10 Ni-0.7 Mn wire the fatigue limit of the LTT joint could be twice that of conventional joints. Barsoum et al. [13] studied the effect of residual stress on fatigue strength. Fatigue tests showed that the LTT joint had a 40% increase in fatigue strength compared to conventional joints. Fabrice et al. [14] found that the LTT wire significantly improved the fatigue strength of the joint, and the fatigue strength was 60% higher than that of the conventional wire (G3Si1) filling joint in two million cycles. Wang et al.[15] compared the conventional wire of C-Mn and LTT wire of 9.1 Cr-8.5 Ni-1.25 Mn, and showed that the fatigue strength was improved by 59% when using LTT wire. Altenkirch et al.[16] simulated the stress state of the welded structure during service and analyzed the changes in its organization and performance. The results showed that the low transfor...

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Use of Martensitic Stainless Steel Welding Consumable to Substantially Improve the Fatigue Strength of Low Alloy Steel Welded Structures

Cited by 2 publications

References 7 publications

Preheating Temperature Effect on Crystal Structure and Texture of Martensitic Stainless Steel

Preheating Temperature Effect on Crystal Structure and Texture of Martensitic Stainless Steel

The Effect of Martensitic Phase Transformation Dilation on Microstructure, Strain–Stress and Mechanical Properties for Welding of High-Strength Steel

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