Superior bendability of direct-quenched 960 MPa strip steels

Kaijalainen, Antti; Kesti, Vili; Troive, Lars; Arola, Anna-Maija; Liimatainen, Tommi; Hemmilä, Mikko; Kömi, Jukka; Porter, David

doi:10.1016/j.promfg.2018.07.300

Procedia Manufacturing

2018

DOI: 10.1016/j.promfg.2018.07.300

|View full text |Cite

Superior bendability of direct-quenched 960 MPa strip steels

Antti Kaijalainen

Vili Kesti

Lars Troive

et al.

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2021

Publication Types

Select...

Article2

Relationship

Self Cite0

Independent2

Authors

Journals

Cited by 2 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Soft surface layers exhibit increased workhardening capability and, thus, delay the onset of strain localization and crack initiation. [17,18] Other factors that influence the bending behavior are grain size, [19][20][21] crystallographic texture, [22] and microstructural homogeneity. [17,23,24] For example, near-surface hard bands [23] or nonmetallic inclusions, such as large, cuboidal TiN, [15] can lead to the formation of voids due to stress concentration, which subsequently accumulate to cracks and initiate failure.…”

mentioning

confidence: 99%

Bending Behavior of Zinc‐Coated Hot Stamping Steels

Hofer

Stadler

Kurz

et al. 2021

steel research int.

View full text Add to dashboard Cite

The contradictory requirements of increased passenger safety and a simultaneous mass reduction of the body-in-white drive the development of advanced high strength steels in the automotive industry. Especially, components for the safety cell, e.g., reinforcement of B-pillar, bumper, and roof rails, need to be rigid and impede intrusion in the case of a crash event to protect the occupants. [1] For these applications, ultrahigh strength steels with a tensile strength (TS) of up to 2000 MPa and a martensitic microstructure are used. [2] However, their exceptional high strength is accompanied by limited formability, which can be overcome by hot stamping. The combination of shaping by hot forming and the simultaneous microstructure adjustment by quenching in water-cooled dies enables the production of components with complex geometries. Besides the reduced press forces, this manufacturing process also offers the ability to produce tailored blanks and eliminate spring back, which increases with the sheet strength in cold-forming operations. [3,4] While hot stamping was initially used for built-in components, the expansion of their application to more exposed structures leads to the need for corrosion protection. [5] In contrast to AlSi coatings that only provide barrier protection, zinc coatings additionally offer cathodic corrosion protection and, therefore, maintain their protection effect even when the coating layer is breached, e.g., by stone chipping. The major drawback of zinc coatings is their susceptibility to liquid metal embrittlement (LME) during direct hot press forming due to the presence of liquid zinc during deformation. [6] Thus, zinc-coated press hardening steels are mainly produced via the "indirect" process, where the sheet is cold stamped and subsequently subjected to a quenching and calibration operation in the press after full austenitization. Another possibility to avoid LME is by elimination of liquid phases during hot forming. One idea is to increase austenitization time to fully transform the coating into a single-phase solid solution of α-Fe(Zn) ferrite. [7] The disadvantage of this approach, besides the longer process time, is the decreased corrosion protection due to the lower potential difference between matrix and α-Fe(Zn) ferrite compared with zinc-rich Γ-ZnFe. [8] A further possibility is to increase the transfer time [9] or add an additional precooling step [8,10] to solidify all zinc phases, i.e., Γ-ZnFe, prior to the stamping operation. Typical precooling temperatures range between 450 and 650 C. [11] To guarantee a stable process, the composition of the standard hot stamping alloy 22MnB5 has been slightly adapted to 20MnB8. An increased amount of

show abstract

mentioning

confidence: 99%

Bending Behavior of Zinc‐Coated Hot Stamping Steels

Hofer

Stadler

Kurz

et al. 2021

steel research int.

View full text Add to dashboard Cite

show abstract

The effect of mechanical behavior on bendability of ultrahigh-strength steel

Arola

Kaijalainen

Kesti

et al. 2021

Materials Today Communications

View full text Add to dashboard Cite

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Superior bendability of direct-quenched 960 MPa strip steels

Cited by 2 publications

References 7 publications

Bending Behavior of Zinc‐Coated Hot Stamping Steels

Bending Behavior of Zinc‐Coated Hot Stamping Steels

The effect of mechanical behavior on bendability of ultrahigh-strength steel

Contact Info

Product

Resources

About