High-strength structural steels with a structure of low-carbon bainite subjected to thermomechanical treatment

Lauprecht, W.; Imgrund, H.; Coldren, P.

doi:10.1007/bf00664200

Cited by 2 publications

(1 citation statement)

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“…The influence of Nb on structure formation, mechanical properties and weldability has been widely discussed such as by authors [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Studies showed that Nb has a strong influence on the formation of austenite and ferrite structures.…”

Section: Introductionmentioning

confidence: 99%

Overview of HSS Steel Grades Development and Study of Reheating Condition Effects on Austenite Grain Size Changes

Kvačkaj

Bidulská

Bidulský³

2021

Materials

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This review paper concerns the development of the chemical compositions and controlled processes of rolling and cooling steels to increase their mechanical properties and reduce weight and production costs. The paper analyzes the basic differences among high-strength steel (HSS), advanced high-strength steel (AHSS) and ultra-high-strength steel (UHSS) depending on differences in their final microstructural components, chemical composition, alloying elements and strengthening contributions to determine strength and mechanical properties. HSS is characterized by a final single-phase structure with reduced perlite content, while AHSS has a final structure of two-phase to multiphase. UHSS is characterized by a single-phase or multiphase structure. The yield strength of the steels have the following value intervals: HSS, 180–550 MPa; AHSS, 260–900 MPa; UHSS, 600–960 MPa. In addition to strength properties, the ductility of these steel grades is also an important parameter. AHSS steel has the best ductility, followed by HSS and UHSS. Within the HSS steel group, high-strength low-alloy (HSLA) steel represents a special subgroup characterized by the use of microalloying elements for special strength and plastic properties. An important parameter determining the strength properties of these steels is the grain-size diameter of the final structure, which depends on the processing conditions of the previous austenitic structure. The influence of reheating temperatures (TReh) and the holding time at the reheating temperature (tReh) of C–Mn–Nb–V HSLA steel was investigated in detail. Mathematical equations describing changes in the diameter of austenite grain size (dγ), depending on reheating temperature and holding time, were derived by the authors. The coordinates of the point where normal grain growth turned abnormal was determined. These coordinates for testing steel are the reheating conditions TReh = 1060 °C, tReh = 1800 s at the diameter of austenite grain size dγ = 100 μm.

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Section: Introductionmentioning

confidence: 99%