Strict temperature control is crucial during the production of straight seam steel pipes to ensure reliable welds. If the temperature is too low, the weld area may not reach the required temperature, making it difficult for the metal ends to interpenetrate and bond when most of the metal remains solid. Conversely, if the temperature is too high, much of the metal in the weld area is molten. These molten parts are soft and fluid, potentially carrying molten droplets. These droplets also lack sufficient metal for interpenetration. Furthermore, uneven welding can lead to weld voids. Therefore, integrated wastewater treatment equipment manufacturers emphasize the importance of strict temperature control during the production of straight seam welded pipes. Reputable manufacturers possess advanced temperature control technology, enabling them to meet temperature requirements and ensure product quality. Therefore, it is essential to purchase straight seam welded pipes from reputable manufacturers.
Hot-expanded straight seam steel pipes typically operate at around 1200℃, with slightly lower temperatures required for higher carbon content and other alloying elements. A key aspect of heating straight seam steel pipes is minimizing the amount of oxide scale. Especially in hot-rolled steel pipes, the requirements for service life and surface finish are even more stringent for 16Mn straight seam steel pipes. In the production process of 16Mn straight seam steel pipes, since processing is carried out in a hot state, the heating operation is a crucial step in determining the final product. Like a furnace used for heating, the straight seam steel pipe experiences residual stress due to uneven cooling, depending on its function. Residual stress is an internally self-balancing stress without external force. All types of hot-rolled steel sections have this type of residual stress; generally, the larger the cross-sectional size of the steel section, the greater the residual stress. Although residual stress is self-balancing, it still affects the performance of steel components under external forces.
Poor control of the welding temperature of straight seam steel pipes can have adverse effects on deformation, stability, and fatigue resistance. There are two types of furnaces: heating furnaces and reheating furnaces. The former is used to heat the billet from room temperature to the processing temperature; the latter is used to reheat the billet to the required processing temperature during the processing. Improper heating of straight seam steel pipes can lead to defects such as cracks, folds, and eccentricities on the inner or outer surface of the billet, resulting in scrap.
There are many types of heating furnaces for straight seam steel pipes, but a slow-heating furnace is essential. This type of furnace has an annular bottom that rotates slowly. The billet is loaded from the inlet along the diameter of the furnace bottom, and the rotation proceeds to the outlet, where it is heated and homogenized to the specified temperature. The key to this heating operation is to uniformly heat the billet to a suitable processing temperature. Since piercing has a significant impact—meaning the piercing temperature is a crucial factor—the billet temperature during piercing must be strictly controlled.
In the production of straight seam steel pipes, a product called glass lubricant is required. Before the use of glass lubricant, graphite was used as a lubricant because this product was not yet available on the market. However, long-term use revealed some problems: graphite has a very high heat transfer efficiency but very poor insulation. This causes the mold to heat up very quickly during operation, easily leading to wear on the straight seam steel pipes and reducing the product’s lifespan. Therefore, manufacturers have been searching for a product to replace graphite, and that’s where glass lubricant comes in. The reason for using them is that bogie hearth furnaces have many advantages. Firstly, their low heat transfer efficiency provides insulation, and secondly, they extend the equipment’s service life.
Post time: Dec-24-2025