Effect of heat-treatment on-line process temperature on the microstructure and tensile properties of a low carbon Nb-microalloyed steel

Fan, Lei; Wang, Tongliang; Fu, Zhibin; Zhang, Shuming; Wang, Qingfeng

doi:10.1016/j.msea.2014.04.027

Cited by 28 publications

(13 citation statements)

References 27 publications

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“…Dp Dp (7) where fp and Dp are the volume fraction and average size (in nm) of precipitated particles, as shown in Figure 6 and Table 3. The contribution of precipitation strengthening to the YS is summarized in Table 4.…”

Section: Effect Of Cooling Rate On the Ysmentioning

confidence: 99%

“…Hence, an enhanced combination of weldablility, strength and toughness can be achieved at the expense of an elevated YR [4,5]. Extensive investigations [2,[6][7][8] have indicated that an appropriate dual-phase microstructure containing granular bainitic ferrite (GBF) and/or quasi-polygonal ferrite (QPF) and M/A constituent is essential to balance the above described yield strength and YR in plate steel produced by TMCP. An increased amount of M/A constituent acting as a mixed hard phase [9][10][11][12] can enhance the stain-hardening capacity of the soft ferrite Round bar specimens with length × diameter of Φ 75 × 15 mm were cut from the plates, and thermo-mechanically processed using a Gleeble 3500 system; the process routings are shown schematically in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…The controlled cooling processes were conducted with commencing at 780 • C, cooling to 450 • C at four different rates of 5-20 • C/s, re-reddening up to 500 • C for promoting the carbon atom diffusion from α to metastable austenite (γ ), and air-cooling to room temperature. constituent acting as a mixed hard phase [9][10][11][12] can enhance the stain-hardening capacity of the soft ferrite phase [2,[6][7][8]13] and correspondingly lower the YR, which has been achieved by the addition of nitrogen to V-microalloyed steel [8], and the accelerated cooling followed by heat-treatment on-line process (HOP) of Nb-microalloyed steel [6,7]. Nevertheless, the M/A constituent acting as brittle islands can cause a toughness loss [14][15][16], which can be prevented by grain refinement of soft ferrite phase [17].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Controlled Cooling on Microstructure and Tensile Properties of Low C Nb-Ti-Containing HSLA Steel for Construction

Yang

Wang

Liu

et al. 2017

Metals

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Abstract:The thermo-mechanical control processing (TMCP) of low carbon (C) Nb-Ti-containing HSLA steel with different cooling rates from 5 to 20 • C/s was simulated using a Gleeble 3500 system. The samples' microstructure was characterized and the tensile properties measured. The results show that a microstructure mainly consisting of quasi-polygonal ferrite (QPF), granular bainitic ferrite (GBF), and martensite/austenite (M/A) constituent formed in each sample. Furthermore, the accelerated cooling led to a significant grain refinement of the QPF and GBF, and an increase in the density of dislocations, as well as suppressed the precipitation of nanoscale particles; however, the overall yield strength (YS) still increased obviously. The accelerated cooling also brought about a decrease in amount of M/A constituent acting as a mixed hard phase, which weakened the overall strain-hardening capacity of the QPF + GBF + M/A multiphase steel and simultaneously elevated yield-to-tensile strength ratio (YR). In addition, the mechanisms in dominating the influence of controlled cooling on the final microstructure and tensile properties were discussed.

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Section: Effect Of Cooling Rate On the Ysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Controlled Cooling on Microstructure and Tensile Properties of Low C Nb-Ti-Containing HSLA Steel for Construction

Yang

Wang

Liu

et al. 2017

Metals

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“…1 the steel is microalloyed with niobium in order to accelerate the formation of ferrite and due to grain refinement [21,22]. The steel slabs were hot rolled into plate 15 mm thickness.…”

Section: Experimental Workmentioning

confidence: 99%

Effect of heat treatment on Charpy impact energy of microalloyed steel

et al. 2016

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Original scientific paper In this paper the microalloyed high-strength low-alloy (HSLA) Niomol 490K steel with an addition of niobium (0,032 wt. %) has been investigated. Heat treatment of the steel consisted of austenitisation at 1250 °C for 3 minutes and reheating up to 750 °C for 5 s. After austenitization the quenching was carried out in water with temperature of 70 °C and then in a lead bath up to 400 °C following cooling on the air. It was found that Charpy impact energy is higher and the transition temperature is lower for the transformation of austenite to bainite than to martensite microstructure. Experimental results showed that different fracture surface was observed. It is shown that preferred cleavage fracture occurred in the lattice plane (001) Utjecaj toplinske obrade na Charpy energiju udara mikrolegiranog čelikaIzvorni znanstveni rad U ovom radu istraživan je niskolegirani visokočvrsti čelik Niomol 490K koji sadrži dodatak niobija (0,032 mas. %). Toplinska obrada čelika se sastojala od austenitizacije pri 1250 °C u trajanju od 5 minuta i ponovnog zagrijavanja do 750 °C u trajanju od 5 s. Nakon austenitizacije provedeno je kaljenje u vodi kod temperature od 70 °C i u olovnoj kupci do temperature od 400 °C uz naknadno hlađenje na zraku. Utvrđeno je da je Charpy energija udara viša, a prijelazna temperatura niža za transformaciju austenita u bainit nego kod transformacije austenita u martenzitnu mikrostrukturu. Eksperimentalni rezultati su pokazali različite prijelomne površine. Pokazano je da je preferentno cijepajući prijelom zapažen po ravnini rešetke (001), neovisno o mikrostrukturi.

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“…Os aços microligados tem sido cada vez mais utilizados devido a combinação entre resistência mecânica, tenacidade e boa soldabilidade [1]. A aplicação de microligas como nióbio e titânio aumenta as propriedades mecânicas e possibilita melhor desempenho em produtos que exigem boa soldabilidade (por exemplo, aço para aplicação naval).…”

Section: Introductionunclassified

Efeito Da Adição De Microligas Na Laminação De Bobinas a Quente

David¹,

Oliveira²,

Faria³

et al. 2017

Anais Do Seminário De Laminação E Conformação

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ResumoA laminação de tiras a quente de bobinas de aço apresenta alta relevância devido a possibilidade de obtenção de diversos produtos para diferentes aplicações, tais como: construção civil, industria automotiva e implementos agrícolas. O controle das variáveis de processo, tais como temperatura de reaquecimento de placa, velocidade de resfriamento e temperatura de bobinamento, é determinante para obtenção da microestrutura e, por conseguinte, das propriedades mecânicas do material. O propósito desse trabalho é estudar o comportamento da microestrutura e das propriedades mecânicas com a variação da composição química (adição de microligas de nióbio e titânio), mantendo uma rota de laminação termomecânica similar na laminação de bobinas a quente. Os aços aplicados neste estudo foram o aço microligado ao nióbio e titânio equivalente ao ASTM A1018 HSLAS 50 Classe 1 e o aço carbono comum equivalente ao ASTM A1018 SS36 Tipo 2. Apesar do aço carbono comum apresentar carbono equivalente superior ao aço microligado, foi verificado maior limite de escoamento (σe) no aço microligado ao nióbio e titânio. Dessa forma, aplicando tratamento termomecânico adequado no aço microligado é possível conseguir propriedades mecânicas melhoradas principalmente devido ao refino de grão e ao endurecimento da ferrita. Palavras-chave: Laminação a quente; Tratamento termomecânico; Aço microligado; Steckel. EFFECT OF ADDING MICROALLOYS IN HOT-ROLLED COILS AbstractThe Hot-Rolled Coils from have a high relevance due to the possibility of obtaining various products for different applications, such as: structural steels, automotive industry and agricultural implements. The control of process variables, such as reheating temperature of the plate, cooling rate and coiling temperature is essential to obtain the microstructures and therefore the mechanical properties of the material. The purpose of this work is to study the behavior of the microstructure and mechanical properties by varying the chemical composition (adding the microalloys of Niobium and Titanium) and the similar thermomechanical rolling route in HotRolled Coils. The steels used in this study were the Niobium and Titanium microalloyed steels equivalent to ASTM A1018 HSLAS 50 Class 1 and carbon steel equivalent to ASTM A1018 SS36 Type 2. Despite the carbon steel has a high amount of carbon them the microalloyed steel, we observed higher Yield Strength in the microalloyed steel with Niobium and Titanium. Thus, applying the appropriate thermomechanical treatment in the microalloyed steel, is possible to improve the mechanical properties mainly due to grain refining and hardening of ferrite.

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Effect of heat-treatment on-line process temperature on the microstructure and tensile properties of a low carbon Nb-microalloyed steel

Cited by 28 publications

References 27 publications

Effect of Controlled Cooling on Microstructure and Tensile Properties of Low C Nb-Ti-Containing HSLA Steel for Construction

Effect of Controlled Cooling on Microstructure and Tensile Properties of Low C Nb-Ti-Containing HSLA Steel for Construction

Effect of heat treatment on Charpy impact energy of microalloyed steel

Efeito Da Adição De Microligas Na Laminação De Bobinas a Quente

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