The parameters of this elbow are: bending radius R=400 mm and bending angle θ=90 degrees.

Assume that the elbow diameter is d, the bending radius is r, and the bending angle is θ. The relationship between the bending radius r and the diameter d of a 90-degree elbow can be expressed by the following formula: R = D/2.

This formula shows that the bending radius of an elbow is half the diameter. The bending angle θ is 90 degrees, and no further calculation is needed. The calculation results are: bending radius R=400 mm and bending angle θ=90 degrees.