Forecast of "Trend-Season" Change of Main Product Sales

Taking sales forecast of the main product, the φ108 mm×4.5 mm hot-rolled tube as an example, the author elaborates theoretically and practically how the model for forecast of " Trend-Season " change is used in actual production and sales. In addition, the said model is verified through practice for its correctness, which is so significant for enterprises to make quantitive forecasts for different production/sales targets.