Weld line behaviour during uniaxial tensile testing of tailor welded blanks

The quality of weld line in a tailor welded blank (TWB) is an important factor that can affect the quality of the deep drawing process and resulted drawn parts. Hence, the behaviour of weld line during forming must be made with responsibility and by applying different physical testing methods in order to obtain useful and accurate information. For example, the mechanical properties of TWB and weld line, that give information concerning yield limit and ultimate strength, can be generally determined by applying the following techniques: parallel tensile testing or normal tensile testing. But, since the welding process can induce specific properties in the weld joint and heat – affected zone, the simple tensile test is not enough to obtain the needed information concerning such properties. The present paper investigates the behaviour and mechanical properties of the weld line in a tailor welded blank during and after its tensile testing by applying the following testing methods: parallel tensile test, micro-hardness testing, thermography, EDX and microscopy.