Effect of different Cr contents on tensile and corrosion behaviors of 0.13 pct N-containing CD4MCU cast duplex stainless steels

Jang, Younghwan; Son, Jinil; Kim, Sangshik; Lee, Je-Hyun; Choi, Byunghak

doi:10.1007/s11661-004-0179-4

Cited by 6 publications

(5 citation statements)

References 11 publications

(14 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In duplex stainless steels, austenite has been believed to be a soft phase and the strength was enhanced by increasing the amount of ferrite. 34,35) However, nitrogen in DSS mainly dissolved in austenite due to its high solubility of about 0.45 wt% in the face-centered-cubic (fcc) lattice. 16) Indeed, the effect of the nitrogen content on the strength of austenite is quite important.…”

Section: Discussionmentioning

confidence: 99%

Precipitation of Secondary Phases in Lean Duplex Stainless Steel 2101 during Isothermal Ageing

et al. 2010

View full text Add to dashboard Cite

The DSS ingot was made by standard vacuum melting and casting, which possessed duplex ferritic-austenitic mi- 286© 2010 ISIJ ISIJ International, Vol. 50 (2010) In the present paper, the precipitation behavior of secondary phases in Lean Duplex Stainless Steel (LDX) 2101 had been studied. The alloy has a typical ferritic-austenitic duplex structure after solution treatment. Isothermal ageing treatments were carried out over the temperature range from 700 to 850°C for the period between 2 min and 1 440 min. Cr 2 N-type nitrides were formed as the main product of precipitates, together with small amount of Cr 23 C 6 -type carbides. Increase of N content and decrease of Cr and Mo contents in the steel had led to the absence of s-phase. Due to the solid solution strengthening by interstitial atoms, the hardness value of austenite was measured to be higher than that of ferrite. With increasing the isothermal ageing time, precipitates were observed to be preferentially nucleated at the d/g interface and grown toward the d phase. The d/g interfce migrated from the precipitate particles into d phase, leaving the precipitates behind along the original interfaces, which could increase the size of the secondary austenite (gЈ) phase and decrease the hardness of both austenite and ferrite. Inside gЈ phase, the hardness was measured to increase from about 3.20 GPa at the original interface to about 3.75 GPa at the newly formed interface of d/gЈ. The isothermal kinetics for the precipitation of secondary phases was measured to obey the JMAK-type law. The TTT (time-temperature-transformation) curve was constructed based on the measurements, which seems to have resulted from the overlap of two different precipitated products. The average impact energy at room temperature for the sample after solid solution treatment was measured to be 105 J. When 2 % secondary phases were precipitated during ageing, the impact energy decreased to about 43 J, reduced by about 59 % as compared with the as-annealed sample, indicating that formation of secondary phases can result in dramatic decrease of steel toughness.

show abstract

Section: Discussionmentioning

confidence: 99%

Precipitation of Secondary Phases in Lean Duplex Stainless Steel 2101 during Isothermal Ageing

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Comparing S2 with S3, the higher mass fraction of ferrite caused the higher YS and UTS, although the equiaxed grain size was nearly the same. Jang and Son et al investigated the effect of microstructure on tensile property in CD4MCU cast duplex stainless steels [27][28][29]. They concluded that the YS and UTS increased with increasing mass fraction of ferritic phase, because the ferritic phase had inherently higher strength than the austenitic phase.…”

Section: Improvement Of Tensile Propertymentioning

confidence: 99%

“…It is known that Ti was a strong ferrite forming element, and could promote formation of ferrite in austenitic stainless steel or increase ferrite fraction in duplex stainless steel. Jang et al investigated Cr contents on tensile and corrosion behaviors of 0.13 pct N-containing CD4MCU (0Cr26Ni5Mo2Cu3) cast duplex stainless steels [27]. They found that the tensile behavior of duplex stainless steel increased in a nonlinear manner with increasing Cr content.…”

Section: Introductionmentioning

confidence: 99%

Effect of Titanium Addition on As-Cast Structure and High-Temperature Tensile Property of 20Cr-8Ni Stainless Steel for Heavy Castings

Wang

Cheng

Hou

2020

Metals

View full text Add to dashboard Cite

20Cr-8Ni stainless steel is used to manufacture heavy castings in industrial practice. Owing to the slow solidification rate of heavy castings, the as-cast structure is usually coarse, which reduces the mechanical properties. To refine the solidification structure, the effect of titanium addition on the as-cast structure and high-temperature tensile property was investigated in the laboratory. The ingots with 0.0036, 0.2, and 0.45 mass percent titanium were produced in the laboratory. On the basis of experiment and thermodynamic calculation through Thermo-Calc software, the typical inclusions changed from dual phase Si-Mn-Ti oxides to pure TiN or complex Ti2O3 + TiN with titanium content increasing. The equiaxed grain ratio of ingot increased from 51 percent to nearly 100 percent, and the size of equiaxed grain decreased owing to heterogeneous nucleation of δ-Fe. Besides, the equilibrium solidification model changed from the FA model to the F model, and the mass fraction of ferritic phase in ingots increased from 24.8 to 42.6 percent. As a result, the yield strength and ultimate tensile strength of ingots increased gradually, but the tensile elongation changed little owing to the increase of ferritic phase mass fraction and decrease of equiaxed grain size.

show abstract

“…Therefore, DSS is replacing conventional austenitic or ferritic stainless steels in many industrial applications because of its combined advantages of better mechanical and corrosion properties. [1][2][3][4][5] DSS contains austenite stabilizing elements like Ni, Mn, C, N and Cu as well as ferrite stabilizing elements like Cr, Mo and Si. The recent skyrocketing raw material cost stimulates development of the DSSs with less alloying.…”

Section: Introductionmentioning

confidence: 99%

In-situ Observation of δ↔γ Phase Transformations in Duplex Stainless Steel Containing Different Nitrogen Contents

Zhao

Sun

et al. 2017

ISIJ International

View full text Add to dashboard Cite

The characteristics of the γ ↔δ phase transformations were observed on the surface of duplex stainless steels with different nitrogen concentrations by the Ultra High Temperature Confocal Laser Scanning Microscope (UHT-CSLM). The effects of the nitrogen content on the phase transformations are discussed based on the experimental results and thermodynamic calculations. It is found that the migration of the δ/γ IB is the main form of the phase transformation and leads to the continuous decline and final disappearance of the retained γ-phase during the γ→δ phase transformation in the high nitrogen steel (N1) and low nitrogen steel (N2). During the δ→γ phase transformation, the γ -cells prefer to precipitate along the δ/δ GBs and develop into the δ -ferrite matrix with finger-like or sword-like patterns. Then the γ-cells also nucleate in the δ -grains with a sword-like pattern and the growing speed in the longitudinal direction is much faster than that in the lateral direction. More importantly, the high nitrogen content can hinder the migration of δ/γ IBs during the γ→δ transformation and also promote the nucleation and growth of γ -phase during the δ→γ transformation by increasing both the starting and finishing temperatures of the phase transformation. Interestingly, the original δ/δ GB which is covered by the precipitation of γ -phase during the δ→γ transformation will reappear first at the same position by the moving of δ/γ IBs during the γ→δ transformation, but it is unstable and migrates fast with further heating.

show abstract

Effect of different Cr contents on tensile and corrosion behaviors of 0.13 pct N-containing CD4MCU cast duplex stainless steels

Cited by 6 publications

References 11 publications

Precipitation of Secondary Phases in Lean Duplex Stainless Steel 2101 during Isothermal Ageing

Precipitation of Secondary Phases in Lean Duplex Stainless Steel 2101 during Isothermal Ageing

Effect of Titanium Addition on As-Cast Structure and High-Temperature Tensile Property of 20Cr-8Ni Stainless Steel for Heavy Castings

<i>In-situ</i> Observation of <i>δ</i>↔<i>γ</i> Phase Transformations in Duplex Stainless Steel Containing Different Nitrogen Contents

Contact Info

Product

Resources

About