Crack Detection on Sheared-Edge of Ultra-High Strength Steel Sheet by Using Acid Immersion

Azzmer S.; Jaafar H.; Tajul L.; Sulaiman M.H.; Zailani Zainal Abidin

Crack Detection on Sheared-Edge of Ultra-High Strength Steel Sheet by Using Acid Immersion

Journal

IOP Conference Series: Materials Science and Engineering

ISSN

17578981

Date Issued

2020-07-09

Author(s)

Azzmer S.

Jaafar H.

Tajul L.

Sulaiman M.H.

Zailani Zainal Abidin

Universiti Malaysia Perlis

DOI

10.1088/1757-899X/864/1/012176

Handle (URI)

https://hdl.handle.net/20.500.14170/5232

Abstract

In trimming of ultra-high strength steel (UHSS) sheet, the high strength of the sheet usually results in large fracture and low burnish surfaces on the sheared-edge. For metal stamping industries, large fracture surfaces are unwanted, as it not only deteriorates sheared-edge quality but also leads to delayed-crack. In this study, crack detection by using acid immersion on the sheared-edge of ultra-high strength steel sheet caused by the trimming process was investigated. The ultra-high strength steel sheet of JSC780YN, JSC980YN, and JSC1180YN having different strengths were trimmed and immersed in 35% hydrochloric acid under a controlled time interval. The steel sheet with higher strength was found to produce larger fracture surface after trimming, i.e. more than 50% of the entire sheared-edge is fracture surface. Besides, the larger fracture surface of the steel sheet results in higher crack exposure and higher crack propagation, which in the long run, it can cause failure to the part manufactured using UHSS.