| 摘要 |
<p>The present invention relates to an impact beam of a vehicle door, which has high strength and is resistant to breakage caused by impact and a manufacturing method thereof. According to a preferred embodiment of the present invention, the manufacturing method of the impact beam of a vehicle door may include: a step (S10) of preparing a multi-tube base material wherein an inner tube is inserted into an outer tube; a step (S20) of heating the multi-tube base material at temperatures higher than an austenitic denaturalization temperature; a step (S30) of cladding the multi-tube base material heated in the step (S20) by contracting the multi-tube base material using a stretch reducing mill (SRM); and a step (S40) of denaturalizing the inner tube into a martensitic structure by cooling the multi-tube base material cladded in the step (S30).</p> |
