You see it mathematically....Cooling rate is given as Gradient* Growth rate..... At the center of the weld pool, in the trailing half , growth rate R is much higher and G is quite less.... This product is more at the center than at the fusion line....At fusion line, G is higher but R is too less so the product is less..
the temperature gradient between the center to the fusion zone is much higher than the temperature gradient between the fusion zone and the rest of the metal. Hence highest cooling rate is attained within a region where spatial variation in temperature is at their highest
Dear sir,
Can you please elaborate how cooling rate is higher (fast) at weld center and lower (slow) at the fusion boundry? ( Video timer - 27: 30)
You see it mathematically....Cooling rate is given as Gradient* Growth rate..... At the center of the weld pool, in the trailing half , growth rate R is much higher and G is quite less.... This product is more at the center than at the fusion line....At fusion line, G is higher but R is too less so the product is less..
the temperature gradient between the center to the fusion zone is much higher than the temperature gradient between the fusion zone and the rest of the metal. Hence highest cooling rate is attained within a region where spatial variation in temperature is at their highest