In sheet metal operations Strain hardening exponent plays a major role. Quantitative measurement of the strain-hardening characteristic of a material is given by strain hardening coefficient 'n'. It is defined as how rapidly metal becomes harder and stronger. The deformation remaining after an applied load is removed is called plastic deformation. Strain hardening is represented by the exponent 'n' in the flow stress equation, which approximates the relation between true stress and true strain during plastic deformation of a metal. The constant 'n' plays a crucial role in sheet metal forming such as in deep drawing process the materials is possible to state strain hardening exponent from 10 to 20% of deformation. Strain hardening exponent has very strong sensitivity to structure. Strain hardening is a means of strengthening a metal prior to its delivery to the customer. It is also a mechanical property that not only determines how a material strengthens, but how well it forms in a stamping die. This property can be seen in a material’s true stress-strain curve. The strain hardening exponent (n) determines how the metal behaves when it is being formed. Materials that have higher n values have better formability than those with low n values. As metals work harden, their remaining capacity for work hardening decreases. This means that high strength tempers of a given material typically would have lower n values than lower strength tempers of the same alloy. It is the measure of increase in hardness and strength caused by plastic deformation. Two or more sheet metals which are welded together prior to forming are known as tailor welded blanks. Tailor welded blanks of steel alloys tensile specimens are prepared and tested experimentally through uniaxial tensile test in this paper and strain hardening exponent of tailor welded sheet metal blanks is determined.
Volume 11 | 07-Special Issue
Pages: 600-605