초록 ▼

A vehicle structural beam, such as a door intrusion beam, which possesses an elongate tubular beam part which at opposite ends is provided with mounting flanges for securement to a vehicle frame. The elongate tubular beam part and the flanges provided at opposite ends are defined by an integral, one

A vehicle structural beam, such as a door intrusion beam, which possesses an elongate tubular beam part which at opposite ends is provided with mounting flanges for securement to a vehicle frame. The elongate tubular beam part and the flanges provided at opposite ends are defined by an integral, one-piece, monolithic steel structure which has been initially roll-formed from an elongate flat metal sheet to define the closed tubular structure of the tubular beam part, and which has been subjected to heating and quenching so that the elongate tubular beam part is of relatively high strength steel throughout its entire length, whereas the integrally and monolithically joined end flanges remain as lower strength steel which has been significantly unaffected by the heat treatment and quenching so as to permit appropriate shaping thereof and ease of welding to the vehicle frame.

대표청구항 ▼

1. A process for making a structural beam, comprising the steps of:feeding a continuous, low-strength steel sheet having opposing side edges in the lengthwise direction thereof; notching the steel sheet at predetermined intervals to define alternating notched and un-notched sheet portions in the len

1. A process for making a structural beam, comprising the steps of:feeding a continuous, low-strength steel sheet having opposing side edges in the lengthwise direction thereof; notching the steel sheet at predetermined intervals to define alternating notched and un-notched sheet portions in the lengthwise direction of the sheet; roll-forming the steel sheet in the lengthwise direction to form an elongate profile wherein the un-notched portions are formed into three-dimensional profile sections having walls that meet to define a tube; fixedly connecting the meeting walls of the un-notched portions together to rigidly close the tube; heat treating the profile to substantially increase the strength of the steel defining solely the un-notched portions; and forming the notched portions into flanges which are integrally and monolithically joined to opposite ends of the tube which extends throughout the un-notched portion.