The flat steel spring illustrated is loaded in bending by the force F. The spring supports a static weight of exactly 9.36 kN. During operation, the total load on the spring is estimated to fluctuate up to 10.67 kN maximum. The spring is forged of a 95-point carbon steel and after heat treat- ment has the following minimum properties: St 1400 MPa, Sy, 950 MPa, HB = 399, and 32 percent reduction in area. Estimate the factor of safety if the spring is 18 mm thick. 300- = = -150- 10 D. 75 R2