PSI - Issue 36

Odarka Prokhorenko et al. / Procedia Structural Integrity 36 (2022) 290–297 Odarka Prokhorenko, Serhii Hainutdinov, Volodymyr Prokhorenko et al. / Structural Integrity Procedia 00 (2021) 000 – 000 3

292

Fig. 1. Dependence of thermophysical properties on temperature for various phases of steel DC04.

Structural steel DC04 belongs to the group of the low-carbon ferrite-perlite steels and is widely used for manufacturing of the various welded structures. The chemical composition, which determines the properties and behavior of phases during phase transformations of the steel are given in Table 1.

Table 1. Chemical composition (% by mass) for low-carbon steel DC04. Carbon Manganese Silicon Phosphorus

Sulfur 0.025

0.08

0.4

0.07

0.025

3. Heat source and thermal analysis In arc welding, the process of heat distribution in a solid body is described by a non-linear differential equation of thermal conductivity taking into account the acting heat source:

T               =  +  +  +                    T T T t x x y y z z

q vol

c

(1)

,

where λ (T) – thermal conductivity depending on temperature, W/ o C · m; c(T) – specific heat capacity depending on temperature, J/kg · o C; ρ (T) - density depending on temperature, kg/m 3 ; q vol (x, y, z) – volumetric density of the heat source power, W/m 3 . To describe the condition of heat transfer, the third type boundary conditions were used (see the work of Tsvetkov et al. (2006)):

( T h T T n

c     = −     

)

(2)

,

s

s

where n – the normal to the surface; h – the total heat transfer coefficient, which takes into account the heat transfer by convection and radiation, W/ o C · m 2 ; T c and T s - the ambient and surface temperatures, respectively, o C. The index «s» refers to the values on the surface. The boundary value problem (1) – (2) was integrated under the initial condition:

0 ( , , ) T x y z T = ,

(3)

where T 0 =20

o С – initial temperature.