Inflatable thermoforming process of boron steel pipe

Abstract

The invention relates to a gas bulging hot formation process of a boron steel tube. The process comprises the following steps of: (1) bending the tube and preforming; (2) heating boron steel tube parts; (3) conveying the boron steel tube parts to a die; (4) partially or totally closing a die area, moving an axial cylinder to a workpiece, arranging an end socket on the front end of the axial cylinder for sealing both ends of the workpiece; opening an inflow valve in a high pressure gas station, accessing the high pressure gas with initial pressure from the forefront end of the end socket, and filling the boron steel tube parts with the high pressure gas; pressurizing the high pressure gas in the boron steel tube parts to form internal pressure by combining the axial material moving action of the axial cylinder, and completing high pressure forming of the boron steel tube parts at high temperature; the pushing force of the axial cylinder is in the range from 5 to 100 tons and the internal pressure is in the range from 5 to 250MPa; (5) maintaining pressure and quenching; (6) relieving the pressure and opening the die. According to the process, the parts with the material's mechanical strength as much as 1500MPa, and the changed cross-section shape and circumference can be produced.

Description

technical field [0001] The invention relates to a gas expansion thermoforming process of a boron steel pipe, in particular to a boron steel pipe bulging and quenching process under high temperature with internal high-pressure gas, and belongs to the technical field of heat treatment plastic forming. Background technique [0002] As a series of hot-formed steel pipes, the production process of boron steel pipes is divided into two stages: forming and quenching and cooling. Among them: the forming stage needs to be stamped and formed by a mold at high temperature; The transformation from tensite microstructure to martensite microstructure results in extremely high strength and hardness; depending on the type of boron steel, its strength can reach 500-2000MPa. The chemical composition of common boron steels whose strength reaches 1500MPa after hot forming is shown in Table 1. [0003] Table 1 [0004] [0005] The internal high-pressure forming process of pipe fittings use...

AI Technical Summary

Problems solved by technology

Due to the limitations of the pipe making process and the mechanical properties of the material itself, the strength of the applied pipe fittings is limited, and the tensile strength is difficult to exceed 1000MPa

[0008] At present, the hot forming of common boron steel pipes is mostly an ordinary hot stamping process. There is no high-pressure medium inside the forming process, and it can only adapt to products with equal cross-section perimeters, and the product shape is very limited.

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