Development of air-hardening martensitic forging steels

Gramlich, Alexander; Schmiedl, Tobias; Schönborn, Steffen; Melz, Tobias; Bleck, Wolfgang

doi:10.1016/j.msea.2020.139321

Cited by 29 publications

(40 citation statements)

References 14 publications

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“…Additionally, the high concentration of aluminium in lab-4 (

) explains the higher strain hardening rate. The material contains fine homogeneously distributed aluminium nitrides [ 4 ], which are known to decrease the deformability of steels [ 11 ]. The materials deformed at 800

( Figure 6 ) indicated that boron accelerates the start of DRX, as only lab-2 shows a significant peak at this temperature.…”

Section: Discussionmentioning

confidence: 99%

“…However, in the investigated materials the majority of titanium nitrides have diameters on the

-scale for which no effective grain boundary pinning can be expected, leaving the positive effect on the DRX questioned. Additionally, titanium nitrides act as nucleation sites for niobium carbides [ 4 , 15 ], annihilating the effect for this type of precipitates as well. Therefore, only the titanium-free alloys (lab-3 to lab-5) have precipitates, which may influence the DRX.…”

Section: Discussionmentioning

confidence: 99%

“…Five alloys were designed using results from previous studies [ 6 ] and MatCalc computational thermodynamics software (version 6, MatCalc Engineering GmbH , Vienna, Austria). The base concept (

–

carbon, 4

manganese,

silicon and

) was originally modified by different amounts of molybdenum, titanium, boron and aluminium in order to investigated the influence of these elements on grain boundary embrittlement [ 4 ]. The chemical composition of the investigated alloys is displayed in Table 1 .…”

Section: Materials and Methodsmentioning

confidence: 99%

“…This complicates the process control immense, specifically for forging parts with large diameters. Recently, air-hardening ductile forging steels (AHDs) were added to the list, which achieve their martensitic microstructure through air-cooling from the forging heat, but show similar static mechanical properties as Q + T steels [ 4 ]. These materials belong to the group of medium manganese steels (MMnS), as the martensitic microstructure is achieved by an addition of manganese of 4

.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.–% Medium Manganese Steels

2020

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The hot deformation behaviour of air-hardening martensitic forging steels (of type 1.5132) is presented. The newly developed steels are characterized through dilatometric tests as well as through microstructure analyses with LOM and SEM and hardness measurements. Additionally, the influence of alloying elements on the flow curves at high temperatures is discussed. It is demonstrated that the higher alloying content does not increase the equivalent stresses in comparison to the reference alloys and contrariwise reduces the offset for dynamic recrystallization at temperatures below 1100 ∘C. Furthermore, the effect of different alloying elements on the strain hardening behaviour during hot compression of 4wt.–% medium manganese steels is presented. It is shown that boron reduces the offset for dynamic recrystallization if present in solid solution, while the combined addition of titanium and niobium annihilates the solid drag effect on the prior austenite grain boundaries.

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“…Additionally, the high concentration of aluminium in lab-4 (

( Figure 6 ) indicated that boron accelerates the start of DRX, as only lab-2 shows a significant peak at this temperature.…”

Section: Discussionmentioning

confidence: 99%

“…However, in the investigated materials the majority of titanium nitrides have diameters on the

Section: Discussionmentioning

confidence: 99%

“…Five alloys were designed using results from previous studies [ 6 ] and MatCalc computational thermodynamics software (version 6, MatCalc Engineering GmbH , Vienna, Austria). The base concept (

–

carbon, 4

manganese,

silicon and

Section: Materials and Methodsmentioning

confidence: 99%

.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.–% Medium Manganese Steels

2020

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“…b) Charpy V‐notch impact energy at room temperature versus yield strength for different forging steels. [ 8 ]…”

Section: Introductionmentioning

confidence: 99%

Behavior of Forging Steels under Cyclic Loading—the Benefit of Air‐Hardening Martensites

Schmiedl

Gramlich

Schönborn

et al. 2020

steel research int.

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The development of air-hardening martensitic forging (LHD: luft härtend duktil) steels offers high material performance with a short and simple process route. In this study, five alloys (L1-L5), based on the existing LHD alloy concept but with different contents of aluminum, titanium, boron, and molybdenum, are cast at laboratory scale. The casted blocks are hot forged into semifinished products and cooled in air (uncontrolled). The tensile properties, the Charpy V-notch impact energy, the cyclic material behavior, and the fatigue strength of the alloys L1-L5 are opposed to each other. Furthermore, the material properties are compared with the standard quench and tempered (QþT) steel 42CrMo4 (reference material) and ranked against previously developed forging steels. The tensile properties and Charpy V-notch impact energy are comparable with those of the reference material, whereas the new alloy concepts show a significantly higher cyclic yield strength and fatigue strength.

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Air Cooling Martensites—The Future of Carbon Neutral Steel Forgings?

et al. 2023

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The air‐hardening ductile forging steels belong to the third generation of advanced high‐strength steels and achieve their final, martensitic microstructure simply by air cooling from the forging heat. The present conference paper reviews the 15 years of development, different alloying strategies, and metallurgical throwbacks like manganese embrittlement. Furthermore, the most recent results concerning microstructure, mechanical properties, and cyclic material behavior obtained from an industrial trial melt are discussed together with the implications of these results on the carbon footprint (CF) and their impact on the resource efficiency of forged steel components. It is demonstrated that the CF of a steel product needs to be discussed on different levels, as the material‐, process‐, and product‐level contributions need to be considered. Furthermore, a case is made for new high‐strength steels in the context of circular economy, as increase fatigue resistance enables lightweighting potentials.

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Development of air-hardening martensitic forging steels

Cited by 29 publications

References 14 publications

Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.–% Medium Manganese Steels

Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.–% Medium Manganese Steels

Behavior of Forging Steels under Cyclic Loading—the Benefit of Air‐Hardening Martensites

Air Cooling Martensites—The Future of Carbon Neutral Steel Forgings?

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