Effect of step cooling process on microstructures and mechanical properties in thermal simulated CGHAZ of an ultra-high strength steel

Guo, Xingwu; Shi-chang, Liu; Xu, Jijin; Wang, Shuai; Fu, Liming; Chai, Ze; Lü, Hao

doi:10.1016/j.msea.2021.141827

Cited by 15 publications

(5 citation statements)

References 42 publications

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“…As an important welding parameter, the cooling rate plays an important role in the microstructure and strength–toughness balance of steel [ 11 ]. Guo et al [ 12 ] studied the coarse-grained HAZ (CGHAZ) of UHSS with different cooling rates. The results showed that by adjusting the cooling rate, the strength and toughness of CGHAZ can be comparable to those of base metal.…”

Section: Introductionmentioning

confidence: 99%

Inter-Critically Reheated CGHAZ of Ultra-High-Strength Martensitic Steel with Different Cooling Rates

Liu

Zhou

et al. 2023

Materials

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The mechanical properties of steel’s inter-critically reheated coarse-grained heat-affected zone (ICR CGHAZ) directly affects the service life of machinery equipment. The hardness and toughness of ICR CGHAZ can be optimized simultaneously through tailoring microstructure where cooling rate plays a key role. In this work, the samples with different cooling rates was prepared using thermal simulation. The granite bainite (GB), bainite ferrite (BF) and MA were formed at a 1 °C/s (CR1) cooling rate, while BF and MA were formed at 10 °C/s (CR2) and 30 °C/s (CR3) cooling rates. With the increase of cooling rate, the effective grain size decreased and the number of hard phases increased, resulting in monotonic increase of hardness(260HV3, 298HV3 and 323HV3). CR1 had sparsely distributed coarse slender MA and CR3 possessed tail-head connected MA along PAGBs, which was detrimental to toughness. Therefore, CR2 possessed the best toughness(25J). The microstructural evolution mechanism of ICR CGHAZ with different cooling rates is investigated, corresponding hardening and toughening mechanisms are discussed.

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Section: Introductionmentioning

confidence: 99%

Inter-Critically Reheated CGHAZ of Ultra-High-Strength Martensitic Steel with Different Cooling Rates

Liu

Zhou

et al. 2023

Materials

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“…Xiong et al [12] investigated the microstructure and mechanical properties of ultra-high strength steel with a bainitic ferrite/martensite dual-phase structure. Meanwhile, Guo et al [13] found that different cooling rates have a significant impact on the microstructure and mechanical properties of UHSS. These latest Processes 2023, 11, 1349 2 of 13 research results indicate that through controlled rolling and controlled cooling processes, the microstructure and properties of ultra-high strength steel can be modulated, enabling wider applications.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, Guo et al [13] found that different cooling rates have a significant impact on the microstructure and mechanical properties of UHSS. These latest Processes 2023, 11, 1349 2 of 13 research results indicate that through controlled rolling and controlled cooling processes, the microstructure and properties of ultra-high strength steel can be modulated, enabling wider applications. In addition, deep cryogenic treatment (DCT) is a new method of improving the mechanical properties of UHSS by cooling it to extremely low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Effects of Deep Cryogenic Treatment and Controlled Rolling on Microstructures and Mechanical Properties of an Ultra-High Strength Steel

Yong-li

Zhou

et al. 2023

Processes

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The microstructure mechanisms and mechanical properties of 0.23C-1.96Si-1.94Cr-1.93 Mn-0.35 Mo ultra-high strength steel treated by the deep cryogenic treatment at −196 °C were investigated after the steel was hot rolled at different temperatures. Experimental results show that austenitizing zone rolling with a large reduction in a single pass can comprehensively enhance the mechanical properties due to the high volume of retained austenite and refined lath martensite and bainite. The high strain gradient was suppressed, and tensile strength, yield strength, impact toughness, and total elongation were 2221 MPa, 2017 MPa, 65.5 J, and 16.9%, respectively. In addition, the austenitizing zone rolling can promote the formation of film retained austenite more than dual phase zone rolling, and retained austenite was decreased with an increase in rolling pass in a total rolling reduction of 75%. It is demonstrated that deep cryogenic treatment after austenite zone rolling with a large reduction is the proper method to enhance strength and toughness via refinement strengthening and retained austenite. This work not only reveals that the effects of refinement strengthening and high strain gradients can be markedly improved by deep cryogenic treatment after austenitizing zone rolling with large reduction strategies, but also provides a realistic preparation technology for the exploitation of superior steel applications.

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“…With the increasing requirements for energy-saving and safety, ultra-high-strength steel (UHSS) with excellent comprehensive properties of strength, toughness, ductility, and fatigue is widely used in the automobile industry [ 1 , 2 , 3 ]. Hot stamping is the most effective method to produce UHSS components [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

A Tailored Preparation Method of Variable Strength for Ultra-High-Strength Steel Sheet and Mapping Mechanism between Process and Property

Quan

Zhang

et al. 2022

Materials

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The spatiotemporal phase transformation during hot stamping would considerably effect the microstructure and mechanical properties of steels. In order to manufacture hot-stamping components of ultra-high-strength steel with tailored mechanical properties, the effect of the quenching time and the temperature of the die on the phase-transformation characteristics and mechanical property of ultra-high-strength steel was deeply studied. A finite element (FE) model coupled with a thermomechanical phase was employed to perform a succession of simulations for hot stamping corresponding to different quenching times and the temperatures of die, and the corresponding hot stamping experiments were performed. The 3D mapping surfaces of the temperature; quenching time; and three microstructures, namely austenite, bainite, and martensite, were constructed, and the mapping relationships in such surfaces were further explained by microstructural observations. Subsequently, based on the test results of the mechanical properties, the relationship curves of hardness and tensile strength, hardness, and elongation at break were fitted respectively, and then the 3D mapping surfaces were constructed for hardness, tensile strength, and elongation at break, which varied with the temperature die and quenching time. Finally, the quenching parameters of the automobile B-pillar were designed according to the constructed mapping relationship, and the hot-stamping FE simulation of the automobile B-pillar was developed. The result shows that those constructed mapping surfaces are helpful for adjusting the local mechanical property of the steels by designing the parameters.

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Effect of step cooling process on microstructures and mechanical properties in thermal simulated CGHAZ of an ultra-high strength steel

Cited by 15 publications

References 42 publications

Inter-Critically Reheated CGHAZ of Ultra-High-Strength Martensitic Steel with Different Cooling Rates

Inter-Critically Reheated CGHAZ of Ultra-High-Strength Martensitic Steel with Different Cooling Rates

Effects of Deep Cryogenic Treatment and Controlled Rolling on Microstructures and Mechanical Properties of an Ultra-High Strength Steel

A Tailored Preparation Method of Variable Strength for Ultra-High-Strength Steel Sheet and Mapping Mechanism between Process and Property

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