Inclusion phases and the nucleation of acicular ferrite in submerged arc welds in high strength low alloy steels

Dowling, J. M.; Corbett, J. M.; Kerr, H. W.

doi:10.1007/bf02650098

Cited by 170 publications

(90 citation statements)

References 19 publications

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“…Ohkita showed that oxide particles, including TiO, could promote nucleation sites for acicular ferrite precipitation. 15) Several mechanisms for this phenomenon have since been suggested: 1) Influence on the interfacial energy between the particles and austenite, [16][17][18] 2) Influence on the crystal epitaxy between the particles and both of austenite and ferrite phases, 15,19) 3) Influence on the thermal expansion between the particles and austenite, 20) 4) Effect of the depletion of Mn around the particles associated with MnS precipitation at a oxide particle as a nucleation site. 21,22) In welding steels, it was confirmed that TiN, VN and MnS particles, smaller than 0.5 mm with population higher than 10 4 /mm 3 , could refine grains.…”

Section: Introductionmentioning

confidence: 99%

Micro-structure Refinement in Low Carbon High Manganese Steels through Ti-deoxidation—Inclusion Precipitation and Solidification Structure

Kikuchi

Nabeshima²,

Kishimoto³

et al. 2008

ISIJ Int.

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Section: Introductionmentioning

confidence: 99%

Micro-structure Refinement in Low Carbon High Manganese Steels through Ti-deoxidation—Inclusion Precipitation and Solidification Structure

Kikuchi

Nabeshima²,

Kishimoto³

et al. 2008

ISIJ Int.

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“…27) Therefore, it is con- sidered that TRZ complex oxides promote AF nucleation due to the low disregistry associated with the AF-TRZ orientation relationship. Since some AF crystals do not satisfy any clear rational orientation relationships with the oxide, it is presumed that oxide particles acted as inert substrates for heterogeneous nucleation 14) or AF nucleation occurred on oxides present outside of the plane of imaging.…”

Section: Formation Mechanism Of Af On Ti-rem-zr Complex Oxidementioning

confidence: 99%

“…[4][5][6] Many studies have been done to identify oxides that promote AF formation and to establish the mechanism of AF nucleation. [7][8][9][10][11][12][13][14] It is well known that Ti oxides have a positive influence on AF nucleation. 10,12,13,15,16) Researchers have pointed out that Ti2O3 incorporates Mn and forms a Mn depleted zone around the oxide, which increases the driving force for decomposition of the surrounding austenite matrix during cooling.…”

Section: Introductionmentioning

confidence: 99%

Acicular Ferrite Formation on Ti-Rare Earth Metal-Zr Complex Oxides

2015

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Acicular ferrite (AF) formation potency of Ti-Rare earth metal (REM)-Zr (TRZ) complex oxide has been investigated in the simulated heat affected zone of low carbon steel. The TRZ complex oxide shows higher AF formation potency than Ti and Al oxides. A TRZ oxide particle is composed of REM-rich and Zrrich phases. AF crystals nucleate on the interface between austenite and the Zr-rich oxide phase, having a crystal structure that is face-centered cubic with lattice parameter of 0.44 nm. The Zr-rich phase and AF have an orientation relationship described by (011)AF//(011)Oxide, [100]AF//[ ]Oxide (the AF-TRZ orientation relationship), which allows good lattice coherency. It is suggested that the formation of this orientation relationship promotes AF nucleation on TRZ complex oxides. The AF also satisfies the Kurdjumov-Sachs (K-S) orientation relationship with the austenite matrix. It is considered that the coexistence of the AF-TRZ and K-S "three phase" orientation relationships is caused by variant selection of AF in addition to the formation of a rational orientation relationship between the Zr-rich oxide phase and the austenite matrix during the HAZ thermal cycle.KEY WORDS: heat affected zone; Ti-Rare earth metal-Zr complex oxide; acicular ferrite.

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“…Fine particles with size 20-50 nm are indicated as (Cu, Mn) 1.8 S with lattice parameter in the range 0.539 to 0.552 nm. Dowling 25) has reported copper-sulfur rich patch, similar to shell-like copper sulfide, on oxide inclusion in submerged arc welds in high strength low alloy steels. Diffraction patterns from TEM and STEM have indicated that the copper-sulfur rich patch has a cubic structure with lattice parameter in the range 0.55 to 0.59 nm.…”

Section: The Crystal Structure and Phase Of Copper Sulfide In Steelmentioning

confidence: 99%

Isothermal Precipitation Behavior of Copper Sulfide in Ultra Low Carbon Steel

2007

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Copper and sulfur are typical residual elements or impurity elements in steel. Sufficient removal of them during steelmaking process is difficult for copper and costly for sulfur. Utilization of copper and sulfur in steel, especially in steel scrap, has been an important issue for a long period for metallurgists.Copper and sulfur may combine to form a copper sulfide, which may provide a prospect to avoid the detrimental effects of copper and sulfur in steel. Unfortunately the formation mechanism of a copper sulfide in steel has not been completely clarified so far. In the present paper, solution treatment of samples containing copper and sulfur are firstly performed at 1 623 K for 2.7ϫ10 3 s followed by quenching into water. The samples are then isothermally heat-treated at 673 K, 873 K, 1 073 K, 1 273 K and 1 373 K for different time followed by quenching into water again. The size, morphology, constituent and crystallography of sulfide precipitates in these samples are investigated by SEM and TEM equipped with EDS. Fine copper sulfides (less than 100 nm) are observed to co-exist with silicon oxide in samples even isothermally heattreated at 1 373 K for 1.44ϫ10 4 s; Film-like copper sulfides are generally observed to co-exist with iron sulfide in all samples; Plate-like copper sulfides are observed especially in sample isothermally heat-treated at 1 073 K for 1.44ϫ10 4 s. The formation mechanisms of these copper sulfides have been discussed in detail.KEY WORDS: copper sulfide; isothermal precipitation; morphology; crystallography; ultra low carbon steel.up to 780 K at 36.60 at% S and down to 345 K at 35.65 at% S. Therefore, the high Digenite is the most probable phase that is expected in steel at high temperature. But people have confusedly presumed and reported several crystal structures and phases, 11,[13][14][15]20) for example cubic Cu 1.8 S or Cu 1.6 S or CuS 2 , hexagonal CuS and rhombohedral Cu 1.6 S and so on, for copper sulfide in steel.In the previous papers, 5,6,8) the authors found that copper sulfides could be formed in strip casting steel. Differently from the formerly reported copper sulfides in steel/ iron, [10][11][12][13][14][15] which usually coexisted with MnS, almost pure copper sulfides with various morphologies were found in the previous strip casting steels. In the present paper, the formation mechanism such as precipitation temperature, stability and crystallography of various copper sulfides have been investigated during isothermal heat treatment process. Experimental Procedures Materials and Heat Treatment ConditionsThe chemical composition of the present steel is shown in Table 2. The steel is firstly prepared in an induction heating furnace under flowing argon gas. About 350 g of electrolytic iron is melted at 1 873 K. After the alloying elements (Cu, S) are added to the melted iron, the melt is cooled to room temperature with the furnace. An ingot with size of f40ϫH50 mm (hereafter named as sample H00) then could be obtained for the following heat treatment.The solution treatment o...

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Inclusion phases and the nucleation of acicular ferrite in submerged arc welds in high strength low alloy steels

Cited by 170 publications

References 19 publications

Micro-structure Refinement in Low Carbon High Manganese Steels through Ti-deoxidation—Inclusion Precipitation and Solidification Structure

Micro-structure Refinement in Low Carbon High Manganese Steels through Ti-deoxidation—Inclusion Precipitation and Solidification Structure

Acicular Ferrite Formation on Ti-Rare Earth Metal-Zr Complex Oxides

Isothermal Precipitation Behavior of Copper Sulfide in Ultra Low Carbon Steel

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