The critical amount of nitrogen on the formation of nitrogen gas pores during solidification of 25Cr-7Ni duplex stainless steels

Park, Young-Hwan; Kim, Jongwan; Kim, Sun-Koo; Lee, Yong-Deuk; Lee, Zin-Hyoung

doi:10.1007/s11663-003-0077-y

Cited by 11 publications

(3 citation statements)

References 9 publications

(8 reference statements)

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“…Manganese is an element that stabilizes the austenite phase and increases nitrogen solubility at the same time, since nitrogen has a much higher solubility in austenite than ferrite phase. So it can be expected that an increase of Mn content in duplex stainless steel can suppress the formation of nitrogen gas pores [15], [16].…”

Section: Gas Pores In Nitrogen Alloying Stainless Steelsmentioning

confidence: 99%

Nitrogen Alloying of High Chromium Steels by Gas Injection in the Ladle

Machovčák¹,

Carbol²,

Opler³

et al. 2014

Acta Metall. Slovaca Conf.

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There is a steadily increasing demand for steel grades with increased nitrogen content in a certain range. Nitrogen is an important alloying element and it has a beneficial effect on mechanical and corrosion properties of stainless steel. Increased nitrogen content has a positive effect on the increasing of the pitting resistance equivalent in case of duplex stainless steels. Nitrogen can also substitute expensive nickel that strongly supports its use. There are several ways to increase nitrogen content in the steel. One of the most used ways is the nitrogen gas injection in the ladle. Solubility of nitrogen is significantly influenced by the chemical composition of the steel. However, due to nitrogen enrichment in the remaining liquid, gas pores can be formed during solidification of nitrogen-rich stainless steels. This article describes the results obtained during production of high nitrogen steels at steel plant VÍTKOVICE HEAVY MACHINERY a.s., mainly during production of martensitic 9% chromium steels and super duplex stainless steels.

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Section: Gas Pores In Nitrogen Alloying Stainless Steelsmentioning

confidence: 99%

Nitrogen Alloying of High Chromium Steels by Gas Injection in the Ladle

Machovčák¹,

Carbol²,

Opler³

et al. 2014

Acta Metall. Slovaca Conf.

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“…The removal methods for nitrogen pores in ingots typically involve changing the solidification mode, increasing solidification pressure, and optimizing the alloy composition design. [10,[17][18][19][20][21] Due to the large difference in the solubility of nitrogen elements in ferrite, martensite, and austenite, changing the solidification mode will lead to the change of nitrogen solubility during the solidification of molten steel. Arola et al demonstrated that altering the solidification mode from pure ferrite to ferrite-austenite in duplex stainless steel would reduce the susceptibility to the formation of nitrogen pores.…”

Section: Introductionmentioning

confidence: 99%

Revealing the Removal Mechanism of Vanadium Addition on Nitrogen Pores in 30Cr15Mo1N High‐Nitrogen Steel Ingot

Zhu,

Ni,

et al. 2023

steel research int.

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The removal mechanism of vanadium addition on nitrogen pores in 30Cr15Mo1N ingot is systematically investigated through statistical analysis and theoretical calculation. The nitrogen solubility is obtained by the thermodynamic model, and the nitrogen content is obtained by combining the ProCAST software and the C–K model. Then, according to the formula of critical nucleation radius and growth rate of nitrogen bubbles, the variation of critical nucleation radius and growth rate of nitrogen bubbles with different vanadium contents is calculated. As the vanadium content increases, the number and mean area of nitrogen pores decrease. In comparison to the 0 V ingot, the number of nitrogen pores decreases in the 0.2 V ingot, but there is an increase in the number of large‐sized nitrogen pores (>3000 μm in diameter). When the vanadium content increases to 0.4, the nitrogen pores are completely removed. The results demonstrate that increasing vanadium content can remove nitrogen pores. Since the solidification mode remains unchanged with increasing vanadium content, increasing the vanadium content cannot remove nitrogen pores by changing the solidification mode of the 30Cr15Mo1N ingots. Therefore, increasing the vanadium content removes the nitrogen pores mainly by inhibiting the nucleation of nitrogen bubbles and promoting nitrogen bubble overflow in 30Cr15Mo1N ingots.

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“…Although Mn can improve the stability of austenite, its effect is much lower than that of Ni [12][13][14]. However, the variation of austenite lattice caused by Mn leads to the expansion of the octahedral gap, which allows more C and N in the austenite for the solid solution [15,16]. The stability of austenite can be significantly influenced by C and N in the material [17].…”

Section: Introductionmentioning

confidence: 99%

Influence of Mn content on rolling performance of lean duplex stainless steel

Chen

Gao

2022

Ironmaking & Steelmaking

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Cold rolling test as well as room temperature compression was carried out to investigated the influence of Mn content on the cold deformation properties of lean duplex stainless steel. The cold deformation mechanism was also discussed by observation of cold-rolled samples with cracks and analysis of the work hardening curve. The results demonstrated that the morphology and size of grains were both influenced by the Mn content. The quenched martensite content varied with Mn content, indicating that Mn plays critical role in both the difficulty of stress-induced martensite transformation of austenite grains in LDSS and the transformation process from austenite to martensite during solution treatment. LDSS with a lower Mn content exhibits lower austenite stability. After quenching, plenty of the austenite was transformed into martensite which performs much higher hardness than ferrite. With the increase in hardness difference between phases, the plasticity of the alloys decreased caused by each phase bore more uneven deformation.

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The critical amount of nitrogen on the formation of nitrogen gas pores during solidification of 25Cr-7Ni duplex stainless steels

Cited by 11 publications

References 9 publications

Nitrogen Alloying of High Chromium Steels by Gas Injection in the Ladle

Nitrogen Alloying of High Chromium Steels by Gas Injection in the Ladle

Revealing the Removal Mechanism of Vanadium Addition on Nitrogen Pores in 30Cr15Mo1N High‐Nitrogen Steel Ingot

Influence of Mn content on rolling performance of lean duplex stainless steel

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