Quenching is an important pipe production step that can also be responsible for geometric distortions in steel parts, depending on cooling heterogeneities, thermal contractions, and changes in the steel microstructure. The quenching stage generally leads to an increase in the outside diameter (OD) of the pipes, and the prediction of the final size becomes key to assuring the quality and dimensional requirements of the product. The objective of this study was to apply simulations based on the finite element method (FEM) to water quenching in tanks to estimate the final OD of a seamless low-carbon steel pipe. This work is a first approach to developing a methodology for predicting quenched pipe distortion that depends on the process parameters used during quenching, e.g., internal and external water jets. In the available scientific literature, there are some approaches to the problem, but a consistent approach was not found, especially concerning the experimental validation of the simulation results, which is always a challenge under industrial conditions. The present research was developed in three stages: temperature measurement at several points of the pipe during the quenching process, heat transfer coefficient (HTC) calculation, and distortion calculation. The first stage was performed on an industrial scale to determine the pipe temperature distribution. Afterwards, a finite element (FE) model was set to conduct the second and third stages. The former covered the HTC prediction for inner and outer pipe surfaces using inverse analysis. Pipe distortions were predicted while taking phase transformations and deformations into account. Finally, experimental temperature profiles during heat treatment were used to predict the HTC and OD growth in the low-carbon pipes. The results of the simulations were compared with the industrial data of a quenched pipe in order to validate the methodology that was used.