Storage tank hemispherical shell forming method for improving mechanical performance

Abstract

The invention relates to a storage tank hemispherical shell forming method. Aiming at the forming production of an aluminum alloy hemispherical shell capable of being strengthened through heat treatment, an aluminum alloy flat plate is hot spun directly and wholly to form a pre-formed blank, and is quenched to spin at a room temperature to form a final-formed blank; the diameter of the final-formed core mold is smaller than the diameter of the pre-formed blank by 2-4 mm; through setting a reasonable spinning gap value, the deformation is about 5-10%; the ageing treatment is performed after the spinning; a final state can reach a 787 state; and the yield strength and the tensile strength of a shell are improved by 10-20% compared with a T62 state of a traditional process (direct quenching and ageing after spinning). Two sets of molds with different diameters are only needed; spun workpieces are excellent in mold bonding; a formed hemispherical shell is high in strength; the optimal performance state of such thermal-treated strengthened aluminum alloys as 2219 exerts; and the advantages of the thermal-treated strengthened aluminum alloys are fully embodied compared with general aluminum alloys incapable of being strengthened through heat treatment.

Description

technical field [0001] The invention relates to a method for forming a storage tank hemispherical shell with improved mechanical properties, and belongs to the technical field of storage tank manufacturing. Background technique [0002] At present, domestic 2219 and other heat-treatable and strengthened aluminum alloy storage tank hemispherical shell forming methods are divided into melon petal forming and integral spinning or stamping of plates into blanks. The melon petals in the former are mainly formed by pre-stretching and quenching with thick plates, and then stretching and aging for final forming. The final state is T87 state with high strength, but the tank shell needs to retain longitudinal welds, and Stretching of thicker plates requires larger tonnage equipment, more processes and more molds, and the wall thickness of the stretched blank is uneven and difficult to control. The latter is subjected to quenching, aging heat treatment and machining after the overall ...

AI Technical Summary

Problems solved by technology

However, according to the current process, quenching and aging heat treatment is carried out after spinning to improve the mechanical properties. The final state of the tank shell is T62 state, and the strength is lower than the best performance state (T87 state) of heat-treatable aluminum alloys such as 2219. , so the advantages of high strength of heat-treatable and strengthened aluminum alloys such as 2219 have not been brought into play, which reduces the design requirements

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