20-mm  diameter steel rod         A=314.16 mm2         E=200 GPa    α=12.0×10-6/C

The figure shows a rod attached to rigid walls on the left and right. The rod is screwed into the wall and bolted firmly on the right. A 15 millimeters diameter bolt connects the rod to a rigid wall on the left.

Set the force-temperature-deformation relationship equal to zero and solve for T.

δ=FLAE+αTL

T=-FαAE=-24,740 N(12.0×10-6/C)(314.16 mm2)(200,000 N/mm2)        =-32.8 C