4. A single pass full penetration weld is made in steel using the following parameters: E-25 V, 1-300 A, n = 0.9, v = 10 mm/sec, To 25C, Tpreheat 200C, Tm = 1510C, PC, =0.0044 J/mmK, k = 0.028 J/mm-sec-C, t = 6 mm a. Identify if it is a thick or thin plate for cooling rate estimation at a temperature, Te-550C [3] b. Calculate the cooling rate. [3] c. Suggest two methods to change the cooling rate, without varying E & 1. [4] d. Show calculations for 50% increase in cooling rate by two methods in (c) [10] Hint: Relative plate thickness factor, r=t Hnet 0.5 For thick plates, R = 2nk(TT); For thin plates, R= 2nkpCp(Tc-To) () Hnet