Point 1 = 130 N/mm2, t = 6 s Stress rate, = 130/ 6 = 21.66 N/mm2s-1 @ 21.66 MPas-1

Point 2 = 253 N/mm2, t = 11 s Stress rate, = 253/ 11 = 23 N/mm2s-1 @ 23 MPas-1

Point 3 = 369 N/mm2, t = 15 s Stress rate, = 369/ 15 = 24.60 N/mm2s-1 @ 24.60 MPas-1

Point 4 = 512 N/mm2, t = 40 s Stress rate, = 512/ 40 = 12.80 N/mm2s-1 @ 12.80 MPas-1

6.005, 130.1734086

15.019, 368.9320782

40.004, 511.7589026

67.004, 489.2031558

-100

0

100

200

300

400

500

600

0 20 40 60 80 100 120

Stress, (N/mm2)

Time, t (s)

(1)

(3)

(4) (5)

11.149, 253.4939215 (2)

Stress vs Time

CALCULATION OF STRESS RATE

Point 5

= 489 N/mm2, t = 67 s Stress rate, = 489/ 67 = 7.30 N/mm2s-1 @ 7.30 MPas-1

As refer to Table 3 in BS EN ISO 6892-1:2009; Modulus of Elasticity of the

material E

MPa

Stress Rate

MPas-1 Min. Max.

150 000 2 20 150 000 6 60

*Note:- 1 psi = 0.00689475729 MPa, 1 F = -17.2222 C

Estimation of modulus of elasticity for carbon steel, E = 30 millions psi/ 0.00689475729 MPa = 206, 843 MPa Thus, As refer to BS EN ISO 6892-1:2009, Clause 10.4.2.5 stated If the testing machine is not capable of measuring or controlling the strain rate, a crosshead separation rate equivalent to the stress rate given in Table 3 shall be used until completeion of yield. As refer to the Table 3; Stress rate () for carbon steel shall within 6 M MPas-1 to 60 MPas-1.