CN116020941A

CN116020941A - Method for controlling rebound of lower section soft zone of B column

Info

Publication number: CN116020941A
Application number: CN202211455462.3A
Authority: CN
Inventors: 何建德; 陈文�; 王作孔; 叶祖君; 谭家爽
Original assignee: Liuzhou Baosteel Auto Parts Co ltd
Current assignee: Liuzhou Baosteel Auto Parts Co ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-04-28

Abstract

The invention discloses a method for controlling rebound of a soft zone at the lower section of a B column, wherein the B column is formed by welding a plurality of sections of materials and then hot-pressing, the tensile strength of the material at the upper section of the B column is larger than that of the material at the lower section of the B column, the lower section of the B column forms the soft zone, the rebound of the soft zone at the lower section of the B column is controlled by arranging rim charge at the edge of the B column, and a hot-pressing die is arranged at the hot-pressing position of the rim charge at the lower section of the B column to form a bent step by the rim charge. The invention can better control the rebound quantity of the soft zone and solve the problem of the dimensional accuracy of parts.

Description

Method for controlling rebound of lower section soft zone of B column

Technical Field

The invention relates to the technical field of automobile parts, in particular to a method for controlling rebound of a soft zone at the lower section of a B column.

Background

At present, with the continuous development of automobile industry technology, the requirements of automobile safety and light weight are also increasing. The B column is a main bearing structure of the side face of the automobile body, is connected with the top cover and the floor, plays an important role in supporting the whole passenger space and fixing the automobile door, is a main stress part in the side collision of the automobile, reasonably transmits the collision force to the whole automobile body through the B column, and ensures the enough safety space of the passenger cabin.

The strength is improved by adopting an ultra-high strength steel thermoforming process in the prior B column forming process, and the ultra-high strength steel thermoforming process can meet the strength requirement, but the part manufactured by the ultra-high strength steel thermoforming process is higher in strength, poorer in toughness, not provided with an energy absorption effect and cannot meet the five-star collision requirement. In order to meet the five-star collision standard of automobiles on the premise of light weight, a poor-strength butt welding thermoforming process is developed in recent years, namely, a B column is formed by hot-pressing after being butt welded by materials with different strengths, the lower section of the B column is made of materials with lower strength, the strength is smaller than that of the upper section, energy can be better absorbed, a soft region is formed, and the soft region formed by the butt welding thermoforming process is weak in strength and high in resilience, so that the requirement on the dimensional accuracy of parts cannot be met.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: the rebound control method for the lower section soft zone of the B column can well control the rebound quantity of the soft zone and solve the problem of the dimensional accuracy of parts.

The technical scheme adopted by the invention is as follows: the method for controlling the rebound of the lower soft zone of the B column comprises the steps that the edge of the B column is provided with rim charge, and a hot-pressing die is arranged at the hot-pressing position of the rim charge at the lower section of the B column, so that the rim charge forms a bent step.

As the optimization of the technical scheme, the strength of the upper section material of the B column is 1300-1500MPa, and the strength of the lower section material is 550-750 MPa.

Compared with the prior art, the invention increases the forming drawing force, balances the drawing force of the end part of the B column, and simultaneously increases the steps in the forming process to ensure that the end part is uniformly attached to the die, and has uniform cooling and balanced internal stress. The invention solves the application of the material with low strength level on the B column, improves the collision performance of the part while realizing the light weight of the part, can well control the rebound quantity, and solves the problem of the dimensional accuracy of the part at the lower section of the B column.

Drawings

Fig. 1 is a schematic view of a blank of a B-pillar of the present invention.

FIG. 2 is a schematic diagram of a B-pillar finished product of the present invention.

Fig. 3 is a schematic diagram of the structure of the B-pillar and the mold of the present invention (before hot pressing).

Fig. 4 is a schematic diagram of a B-pillar and mold structure (after hot pressing) according to the present invention.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples.

As shown in figures 1-4, the invention provides a method for controlling rebound of a soft zone at the lower section of a B column, wherein the B column is formed by hot press molding after welding a plurality of sections of materials, the tensile strength of the upper section of the B column is greater than that of the lower section of the B column, the soft zone is formed at the lower section of the B column, the tensile strength of the upper section of the B column in the embodiment is 1300-1500MPa, and the tensile strength of the lower section of the B column is 550-750 MPa. The rebound control method of the lower section soft zone of the B column comprises the following steps: the edge of the B column is provided with rim charge with a certain width, and the hot pressing die is provided with a step for bending the rim charge at the hot pressing position of the rim charge at the lower section of the B column.

In the concrete implementation of the invention, the rim charge of the B column extends out of the B column by 200-500mm, the steps are arranged in the rim charge range of the side edge or (and) end part of the lower section of the B column, the steps on the lower die are concave steps relative to the hot-pressing surfaces of the upper die and the lower die, the steps on the upper die are convex steps, and when in hot pressing, the convex part of the upper die is pressed into the concave part of the lower die, so that the rim charge at the position is bent, namely, the two sides of the bent position are horizontal, and the bent position is vertical.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A method for controlling rebound of a lower section soft zone of a B column is characterized by comprising the following steps: the B column is formed by welding multiple sections of materials and then hot-pressing, the tensile strength of the upper section of the B column is greater than that of the lower section of the B column, a soft zone is formed at the lower section of the B column, and the rebound control method of the soft zone at the lower section of the B column is that the edge of the B column is provided with rim charge, and a hot-pressing die is arranged at the hot-pressing position of the rim charge at the lower section of the B column to enable the rim charge to form a bent step.

2. The B-pillar lower soft zone rebound control method of claim 1, wherein: the tensile strength of the upper section material of the B column is 1300-1500MPa, and the tensile strength of the lower section material is 550-750 MPa.