Hot stamping of AA6082 tailor welded blanks: experiment and FE simulation

Abstract

-An advanced forming technology, solution Heat treatment, Forming and in-die Quenching (HFQ Ò ), has been employed to form AA6082 tailor welded blanks (TWBs). In comparison with conventional stamping of TWBs, the mechanical properties and formability of AA6082 laser TWBs could be improved under the HFQ Ò forming condition. The TWB was divided into three physical zones, i.e. base metal, heat affected zone (HAZ) and weld zone, based on the hardness distribution. It was found that the degraded hardness of the weldment can be restored after HFQ Ò forming. TWBs of AA6082 with different thickness ratios of 2 (2-1 mm), 1.3 (2-1.5 mm) and 1 (1.5-1.5 mm) were used to study the TWB thickness ratio effects on the forming behaviour. Hemispherical punch dome tests on the TWBs with varying thickness ratios demonstrated different formabilities, and indicated increased displacement of the weld line with increasing thickness ratio. Finite element (FE) modelling was adopted to analyse the weld line movement and strain distributions during HFQ Ò forming.

Transition of failure mode in hot stamping of AA6082 tailor welded blanks

“…performed on the blanks by a Nd:YAG source with a power up to 2.1 kW and a welding speed of 25 mm/s. Uniaxial tensile tests were conducted on a Gleeble 3800 system under HFQ ® condition (Liu et al, 2016), with the temperature ranging from 350 to 525°C and the strain rate from 0.1 to 10 s -1 (Wang et al, 2017b). To determine the forming limit strains of AA6082 at elevated temperature, formability tests were conducted at temperature ranging from 300 to 450˚C, and at forming speeds of 75, 250 and 400 mm/s.…”

“…The SHT is believed to improve the formability by dissolving most of the precipitates into aluminium matrix (Garrett et al, 2005). This material characteristics has been used to form the AA6082 TWBs and the degraded formability of the weldment can be restored at HFQ® conditions, so as the strength after artificial ageing (Liu et al, 2016).…”

A Review on Advance Materials and Techniques Used in Automobile Application

“…The most commonly used welding technology for manufacturing the AA6082 tailor welded blanks is laser beam welding. Laser welding has various advantages, including high productivity, high weld quality in terms of controllable heat affected zone (HAZ) and weld zone, low distortion, flexibility due to the movable heat source, reliability and precision [11,16].…”

“…There were over 210 thermal forming steel production lines worldwide, and more and more models were being used in thermoforming technology. Hot forming technology is applied in the A-pillar, B-pillar, C-pillar, sill, front and rear anti-collision beam, roof side beam and so on [12].…”

Studies on the Hot Forming and Cold-Die Quenching of AA6082 Tailor Welded Blanks

“…The weld area in aluminium TWBs is typically weaker than the base material, which adds difficulty in forming such TWBs. A novel process, solution Heat treatment, Forming and in-die Quenching (HFQ®) has demonstrated its advantages in the forming of AA6082 TWBs with improved formability, as it could eliminate the welding effects and restore the mechanical properties of the welding zone [3].…”