Multi-station continuous hot stamping production line and method

Abstract

A production line sequentially includes a feeding platform, a feeding robot, a pressing unit, a conveying robot, a quenching device, a discharging robot, and a conveyor belt. The pressing unit includes a heating device, a die device, and at least one press used for mounting the die device. The heating device is used for wholly or partially heating the preformed blank to produce a hot blank, and the die device is used for stamping the hot blank, holding the hot blank at a certain pressure, and shaving and punching the hot blank, so as to produce a hot stamped part. The production line can continuously achieve rapid heating, stamping, pressure holding, shaving, punching, and quenching. Heating efficiency is improved, and a transferring process before stamping the hot blank is avoided.

Description

FIELD OF THE INVENTION[0001]The present disclosure relates generally to the technical field of hot stamping, and in particular, to a multi-station continuous hot stamping production line and a method of operating the same.BACKGROUND OF THE INVENTION[0002]Hot stamping is a new technology for forming light-weight and high-strength parts. It has advantages of being able to produce stamped parts having small springback ratio, good fittability and high dimensional accuracy. Use of stamped car parts made of light-weight and high-strength sheet materials can help to improve safety performance of cars and reduce weight of cars, thereby contributing to achievement of light weight of cars.[0003]In a traditional hot stamping process, a preformed blank made of a light-weight and high-strength sheet material is first heated to a hot stamping temperature; then the heated blank is rapidly transferred to a die, immediately stamped, held at a pressure, and quenched to complete a structural transform...

AI Technical Summary

Benefits of technology

[0005]The objective of the present disclosure is to provide a multi-station continuous stamping production line and method, which can continuously achieve rapid heating, stamping, pressure holding, shaving, punching, and quenching, and enhance production efficiency. Heating efficiency is improved, and a transferring process before stamping the hot blank is avoided. For a hot stamped part made of sheet steel, punching and shaving thereof at high temperature avoids an increase of cutting difficulty caused by formation of martensites at normal temperatures. Punching and shaving forces are decreased and desired cutting edges can be obtained.

[0022]The present disclosure achieves the following beneficial effects. By providing the heating device on the press, the preformed blank can be rapidly heated and then stamped at a same place, which achieves a high heating efficiency and speed. In this way, a transferring process before stamping of the hot blank and a transferring device are avoided. Besides, heat loss and air oxidation are reduced. This greatly improves energy utilization and heating efficiency, and ensures surface quality of the hot blank. In addition, in the present disclosure, punching and shaving of the hot stamped part are performed prior to pressure holding and quenching when the strength and rigidity of punching and shaving areas are low, by way of which punching and shaving forces can be reduced and service life of the punching shaving die can be prolonged, and at the same time, a laser cutting process is not used and the production cost is decreased. Furthermore, because a metal material can bear a larger shear force at high temperature due to its improved plasticity, punching and shaving at high temperature can ensure quality of the punching and shaving, and obtain desired cutting edges. Geometrical shapes and dimensional accuracy of hot stamped part can thus be ensured. While decreasing the production cost, the present disclosure also greatly shortens the production time, thereby improving production efficiency.

Problems solved by technology

Existing hot stamping production lines have the following problems.

First, because a blank of ultra-high-strength sheet steel is usually heated in a roller hearth heating furnace, a large amount of heat can be lost in a shaft and in air, which may decrease the heating efficiency.

Second, transferring process of the blank prolongs the production period, and meanwhile the hot blank is contacted with air, which results in great heat loss and oxidation (oxidation is particularly true of bare sheets that are widely used in China).

An oxide coating formed on the sheet can easily wear a surface of the stamping die.

Third, the quenched hot stamped part has an ultra-high strength and rigidity and is usually cut using a laser in practice which is very time-consuming and costing.

In other countries, researches are also being done of hot stamping of aluminum alloy sheets, which, however, has same problems such as low heating efficiency, time-consuming hot blank transferring, rapid cooling of the hot blank, etc.

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