CausedExtruded TubeThe causes of longitudinal cracking are multifaceted, involving both material and process factors. If the drawn tube itself has poor plasticity or improper annealing, the likelihood of longitudinal cracking increases. However, the fundamental reason lies in the relatively high residual stress present in the drawn tube after cold drawing.

From a fracture mechanics perspective, the failure of components is the result of the generation and propagation of internal microcracks. Precision drawn steel pipes have a hollow cross-section and are extensively used as pipelines for conveying fluids, such as oil, natural gas, coal gas, water, and certain solid materials. The longitudinal cracks in precision drawn pipes are primarily brittle fractures, with the crack morphology being open type.

通常, the presence of microcracks in metals is unavoidable. However, whether a fracture occurs under the same material conditions depends on the magnitude of the tensile stress acting on the component. Precision drawn钢管 feature a hollow cross-section and are widely used as piping for conveying fluids, such as oil, natural gas, coal gas, water, and certain solid materials. The tensile stress on the component can be due to external loads or residual stresses inherent within the material.

After cold drawing, especially for hollow drawn tubes, there is a relatively high residual stress present. This stress manifests as tensile stress in the tangential and axial directions near the outer surface of the precision drawn tube, reaching significant values. Precision drawn steel tubes have hollow cross-sections and are extensively used as pipelines for conveying fluids, such as oil, natural gas, coal gas, water, and certain solid materials. Based on the above tensile fracture mechanism, it can be concluded that the tangential residual stress near the outer surface of precision drawn tubes plays a critical role in longitudinal cracking.