A method of computing the operating parameters of a forge welding machine with an electrical operating frequency (F SET) for a preferred effective width of the heat affected zone (X E) during a forge welding of one or more materials forming a weld heating length (y) when the one or more materials move past a forge weld point at a weld velocity (v), each of the one or more materials having: a thermal diffusivity value (ε); an electrical resistivity value (ρ); a relative magnetic permeability value (μ); a density value (γ); a thickness (h); and enthalpy, the method comprising the steps of: (a) determining a trial thermal reference depth (δ) from δ = πεy 4 ⁢ v (b) inputting a trial electrical welding frequency (F 0); (c) determining a trial electrical reference depth (ξ) from ξ = ρ πF 0 ⁢ μ (d) determining a trial normalized electrical reference depth (Z n) equal to the trial electrical reference depth (ξ) divided by the trial thermal reference depth (δ); (e) determining the value of a computed trial normalized width of the heat affected zone (X n) by substituting the value of the trial normalized electrical reference depth (Z n) in a heat affected zone polynomial having the form X n = f(Z n); (f) converting the computed trial normalized width of the heat affected zone (X n) to a calculated width of the heat affected zone (X c) from the product of the computed trial normalized width of the heat affected zone (X n) and the trial thermal reference depth (δ); (g) comparing the difference between the calculated width of the heat affected zone (X c) with the preferred effective width of the heat affected zone (X E); (h) determining if the difference between the calculated width of the heat affected zone (X c) and the preferred effective width of the heat affected zone (X E) is not within a tolerance value of zero, then incrementally changing the trial electrical welding frequency (F 0) and repeating method steps (b) through (h) with the incrementally changed trial electrical welding frequency (F 0); and (i) setting the electrical operating frequency (F SET) of the forge welding machine to the trial electrical welding frequency (F 0) if the difference between the calculated width of the heat affected zone (X c) and the preferred effective width of the heat affected zone (X E) is within a tolerance value of zero. (a) determining a trial thermal reference depth (δ) from δ = πεy 4 ⁢ v (b) inputting a trial electrical welding frequency (F 0); (c) determining a trial electrical reference depth (ξ) from ξ = ρ πF 0 ⁢ μ (d) determining a trial normalized electrical reference depth (Z n) equal to the trial electrical reference depth (ξ) divided by the trial thermal reference depth (δ); (e) determining the value of a computed trial normalized width of the heat affected zone (X n) by substituting the value of the trial normalized electrical reference depth (Z n) in a heat affected zone polynomial having the form X n = f(Z n); (f) converting the computed trial normalized width of the heat affected zone (X n) to a calculated width of the heat affected zone (X c) from the product of the computed trial normalized width of the heat affected zone (X n) and the trial thermal reference depth (δ); (g) comparing the difference between the calculated width of the heat affected zone (X c) with the preferred effective width of the heat affected zone (X E); (h) determining if the difference between the calculated width of the heat affected zone (X c) and the preferred effective width of the heat affected zone (X E) is not within a tolerance value of zero, then incrementally changing the trial electrical welding frequency (F 0) and repeating method steps (b) through (h) with the incrementally changed trial electrical welding frequency (F 0); and (i) setting the electrical operating frequency (F SET) of the forge welding machine to the trial electrical welding frequency (F 0) if the difference between the calculated width of the heat affected zone (X c) and the preferred effective width of the heat affected zone (X E) is within a tolerance value of zero.