explain how to calculate the carborized layer case depth calculation step by step?

2.1 Surface Hardening Format (outer hardness / inner hardness / depth (mm)) (R=150 kg) As Received: 37/44.3/8.6 900C x 15min/Water quench: 5.3 / 71.7 / 12.84 Surface Hardened: Carburized Layer Case Depth Calculat 68 Rc-150 kg D = De -225617.018 m 61 Rc-150 kg D = (2.3x10 -5 ) (8.314)(11737) D 2.0628x10-15 m/? = D? 15 mm x = (2.0628x10 -15 m )(900 ?) com x 1.363x10-6 m o? 1.363