International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Natural gas serves as the primary energy source for heating slabs in the Pusher Furnace prior to their rolling into steel plates. The required quantity of natural gas for a 24-hour operational period must be estimated in advance. This study employs multifactor regression analysis to develop a straightforward yet effective predictive equation for natural gas consumption, incorporating key variables such as projected production, the number of slabs to be heated, effective operating time, and the average dimensions of the slabs over a 24-hour workday. Extensive data collected over an extended period formed the matrix for determining the regression coefficients. The resulting model demonstrates a high correlation coefficient (R² = 0.99), underscoring the accuracy of the regression equation. This indicates that the model reliably predicts natural gas consumption with minimal deviation from actual usage during a 24-hour workday.

In this research work the Welding technology that implements high frequency contact welding process (HFCW), is presented as a method for automatic steel pipes production. The pipes produced by the HFCW are meant to be used for natural gas transportation.
X60M steel coils with thickness of 6.5 mm are used as a raw material. The outer pipe diameter is φ508 and the length is 12000 mm. The preliminary welding procedure is based on the personal experience, technical knowledge and the expert judgment. A special attention has been paid to the most important welding parameters such as: current frequency, voltage and welding speed. After the welding was finished, an additional heat treatment (normalization) of the welded pipes (joints) was performed at the temperature of 900^oC.

In order to justify the proposed welding technology a complex analysis is applied. The first analysis was the chemical analysis of base metal. The next was the nondestructive testing consisted of a visual inspection, and ultrasound testing of the pipes. The destructive testing was consisted of tensile testing, bend testing and the hardness measurement. Besides the analysis of the micro and macro structure of the welded joints, a metallographic analysis is performed as well. Moreover a hydrostatic test and a flattening test were performed as an integral part of the entire testing process. The test results confirmed that the pipes produced with the predicted welding parameters completely fulfilled standard requirements. The manufacturing process for the pipes for natural gas transportation is ready to begin.