The Precipitation Behavior and the Strengthening Effect of NbC during Tempering and during Continuous Cooling

Tanino, Mitsuru; Aoki, Koji

doi:10.2355/isijinternational1966.8.337

Cited by 32 publications

(6 citation statements)

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“…Ti is added to prevent BN formation by preferentially combining with the N allowing B to segregate un-impedingly to the austenite grain boundaries. Tanino [17] has also shown that B segregates to the MnS inclusions much more rapidly than it does to high angle boundaries, so the low S levels in these steels should help B segregation to the austenite boundaries. The hot ductility curves for these 0.5 wt-% V high Al TWIP steels are given in Figure 3.…”

Section: Ti-treated Twip Steelsmentioning

confidence: 99%

Influence of vanadium, boron and titanium on hot ductility of high Al, TWIP steels

Kang

Mintz

2021

Materials Science and Technology

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High Al, twinning induced plasticity (TWIP) steels have high tensile strengths and excellent ductility but low yield strengths compared to other advanced high strength steels and this has limited their application. A.Vanadium addition is a possible answer but cracking on casting is a worry. Hot tensile tests were therefore performed on 1.5% Al, TWIP steels with vanadium levels approximately 0.05–0.7% (all wt-%). Only the 0.05% vanadium steel gave acceptable hot ductility but the room temperature yield strength was too low. In contrast, the Ti–B high 0.5% V steel which was as well as able to give a high yield strength due to precipitation hardening by vanadium carbide gave better ductility by boron segregating to the boundaries and strengthening them.

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Section: Ti-treated Twip Steelsmentioning

confidence: 99%

Influence of vanadium, boron and titanium on hot ductility of high Al, TWIP steels

Kang

Mintz

2021

Materials Science and Technology

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“…Ti is often present to protect the boron in solution so that TiN forms instead of BN. Tanino 72 has shown that boron segregates to high angle boundaries and much more rapidly to the interface of MnS inclusions than to the grain boundaries. Complex (MnS, BN) precipitates are formed which consist of a spherical polycrystalline aggregate of hexagonal BN precipitating out on a spherical nucleus of MnS.…”

Section: Influence Of Boron On Hot Ductilitymentioning

confidence: 99%

Hot ductility of steels and its relationship to the problem of transverse cracking in continuous casting

Mintz¹,

Crowther²

2010

International Materials Reviews

140

237

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The influence of composition and cooling rate on the hot ductility of steels has been reviewed. Models to predict hot ductility behaviour have been discussed and the parts of the trough which can be used to predict the likelihood of cracking occurring are highlighted. On tensile testing both deformation induced ferrite in sufficient quantity to improve ductility and dynamic recrystallisation occur but not when straightening during continuous casting; the strain being too low. This limits the use of the hot ductility curve in predicting cracking behaviour. The temperature range in which straightening of the continuously cast strand should be carried out is either 30uC below the Ar 3 when there is a large amount of ferrite (y40%) present before deformation or above the T d , the temperature at which dynamic recrystallisation starts to take place in a tensile test; this being when the ferrite film no longer forms and precipitates are sufficiently coarse and few in number to influence the ductility. The influence of C,Mn,N, Nb,V,B,Ti,Al and the residuals Cu and Sn on hot ductility are examined and recommendations made with regard to the amounts and cooling conditions required to give freedom from transverse and edge cracks. The hot ductility of the new transformation induced plasticity (TRIP) and twin induced plasticity (TWIP) steels has also been reviewed. P has been shown to have little influence on the hot ductility, but for Al based TRIP and TWIP steels, Al levels need to be closely controlled and high Al levels, (1?5 to 2%Al) are favoured.

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“…The steels all had very low S content ( ≤ 0.003%S) so as to limit the MnS inclusions, the favoured site for AlN precipitation and hence encourage precipitation of AlN in the matrix rather than at the boundaries where it causes the ductility to markedly deteriorate [1,6]. Also, B preferentially segregates to MnS inclusions rather than the grain boundaries [12], and so by reducing the S content, most of the MnS inclusions are removed, and the B is allowed to segregate un-impedingly to the boundaries and improve ductility.…”

Section: Experimental and Resultsmentioning

confidence: 99%

The influence of grain size and precipitation and a boron addition on the hot ductility of a high Al, V containing TWIP steels

Mintz

Kang

Qaban

2021

Materials Science and Technology

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The hot ductility of V containing high Al, TWIP steels was determined at a 1000°C, when no dynamic recrystallisation occurred, and precipitation was too coarse to influence ductility. A change in grain size from ∼1250 to 500 µm caused the reduction of the area to increase by ∼25%, intimating that the improvement in ductility on adding boron is due to its segregation to the boundaries causing grain refinement on solidification. Fine VC precipitation was mainly responsible for deteriorating ductility. In these steels, the ductility of un-recrystallised austenite decreases gradually with increasing temperature from 700°C to 1000°C and this in combination with fine precipitation can markedly change the shape of the hot ductility curve from ductility decreasing to increasing with temperature.

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The Precipitation Behavior and the Strengthening Effect of NbC during Tempering and during Continuous Cooling

Cited by 32 publications

References 0 publications

Influence of vanadium, boron and titanium on hot ductility of high Al, TWIP steels

Influence of vanadium, boron and titanium on hot ductility of high Al, TWIP steels

Hot ductility of steels and its relationship to the problem of transverse cracking in continuous casting

The influence of grain size and precipitation and a boron addition on the hot ductility of a high Al, V containing TWIP steels

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