Investigation of Mechanical Tests for Hydrogen Embrittlement in Automotive PHS Steels

• Main Authors: Renzo Valentini, Michele Maria Tedesco, Serena Corsinovi, Linda Bacchi, Michele Villa
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Metals
• Subjects: hydrogen embrittlement; ultra-high-strength steels; automotive; press-hardened steels; hydrogen-induced delayed fracture; diffusible hydrogen
• Online Access: https://www.mdpi.com/2075-4701/9/9/934

The problem of hydrogen embrittlement in ultra-high-strength steels is well known. In this study, slow strain rate, four-point bending, and permeation tests were performed with the aim of characterizing innovative materials with an ultimate tensile strength higher than 1000 MPa. Hydrogen uptake, in the case of automotive components, can take place in many phases of the manufacturing process: during hot stamping, due to the presence of moisture in the furnace atmosphere, high-temperature dissociation giving rise to atomic hydrogen, or also during electrochemical treatments such as cataphoresis. Moreover, possible corrosive phenomena could be a source of hydrogen during an automobile’s life. This series of tests was performed here in order to characterize two press-hardened steels (PHS)—USIBOR 1500^® and USIBOR 2000^®—to establish a correlation between ultimate mechanical properties and critical hydrogen concentration.