Investigation of Notch-Induced Precise Splitting of Different Bar Materials under High-Speed Load

A notch-induced high-speed splitting method was developed for high-quality cropping of metal bars using a new type of electric-pneumatic counter hammer. Theoretical equations and FE models were established to reveal the crack initiation and fracture mode. Comparative tests were conducted for notched and unnotched bars of four types of steels, i.e., AISI 1020, 1045, 52100, and 304, and the section quality and microfracture mechanism were further investigated. The results show that damage initiates at the bilateral notch tips with peak equivalent plastic strain, and propagates through the plane induced by the notch tip; the stress triaxiality varies as a quasi-sine curve, revealing that the material is subjected to pure shearing at the notch tip, and under compression at the adjacent region. High precision chamfered billets were obtained with roundness errors of 1.1-2.8%, bending deflections of 0.5-1.5mm, and angles of inclination of 0.7°-3.4°. Additionally, the notch effectively reduced the maximum impact force by 21.6-23.9%, splitting displacement by 7.6-18.6%, and impact energy by 27.8-39.1%. The crack initiation zone displayed quasi-parabolic shallow dimples due to shear stress, and the pinning effect was larger in AISI 52100 and 1045 steel; the final rupture zone was characterized by less elongated and quasi-equiaxial deeper dimples due to the combination of shear and normal stress.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:13

Enthalten in:

Materials (Basel, Switzerland) - 13(2020), 11 vom: 28. Mai

Sprache:

Englisch

Beteiligte Personen:

Dong, Yuanzhe [VerfasserIn]
Ren, Yujian [VerfasserIn]
Fan, Shuqin [VerfasserIn]
Wang, Yongfei [VerfasserIn]
Zhao, Shengdun [VerfasserIn]

Links:

Volltext

Themen:

Circumferential notch
High-speed
Journal Article
Metal bar
Precise cropping

Anmerkungen:

Date Revised 28.09.2020

published: Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.3390/ma13112461

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM310620988