Hot formability of DIN 27MnCrB5 steel sheets under controlled thinning

Study on temperature distribution of HSS in hot FLD test

“…2 (a). According to the phenomenon reported in literature [17], the contact with the punch enhances the heat transfer in the center of the sheet. So considering different heat transfer model, the specimen during the FLD test is simplified by two sections, i.e., section S 1 of spherical cap-shaped region ,in which the specimen contact with the punch, and section S 2 of fan-shaped region, where the specimen does not contact with the punch..…”

“…The temperature of area contacted with holder can be taken as same as other parts in the expansion process [20]. Meanwhile, the heat flux distribution of sheet in holder inner is axially symmetric [21].The temperature variation along circumferential direction reported in literature [17] is small during expansion.…”

“…A maximum temperature difference in the hot FLD test at 600 o C was 30 o C with punch speed of 10mm/s in literature [15]. Batalha et.al [17] observed a significant temperature differences on sheet specimen, the contact with the punch caused a most significant decrease of temperature. Under thermal experimental environment, the temperature of sheet specimen decreases sharply in hot stamping tests, the study on the temperature distribution of sheet is essential.…”