Компьютерное моделирование процесса изготовления криволинейного отвода из аустенитной стали на трубогибочном станке с применением нагрева ТВЧ

Abstract

The finite element method was used to evaluate residual stresses and deformations arising in the Du350 bend with a radius of 1200 mm made of the 08Х18Н10Т type austenitic steel during its manufacture with local heating by the high frequency current (HFC) and water cooling. The paper shows that compressive stresses appear on the bend inner surface, and the tensile stresses — on the outer. The bend cross-section acquires the elliptical shape. Maximum deformation in the compression zone reaches 34%, and 22% in the bend tension zone. Heat treatment and hydrotesting influence on the residual stresses magnitude was studied. Based on the tensile test data, characteristics of the metal mechanical properties in various zones of the full-scale bend were determined. It was established that in the non-heat-treated bend an increase in the yield strength (by 10...20%) compared to the original pipe properties was registered in the compressed and tensile zones. Relative elongation in the tensile zone decreased by approximately the same length, and elongation in the tensile zone increased. After heat treatment with heating of up to 900 °C (30 hours), properties in the different bend sections were leveling.