Patent ID: 8652370

Claim:
A hot isostatic pressing method comprising the steps of: accommodating a workpiece in the interior of a high pressure vessel; filling the interior of said high pressure vessel with gas; maintaining the interior of said high pressure vessel at a high temperature and a high pressure for a predetermined time to treat said workpiece; and after the completion of said step of maintaining the interior of said high pressure vessel at a high temperature and a high pressure for a predetermined time to treat said workpiece, cooling said workpiece with reduction in the pressure in the interior of said high pressure vessel, wherein said step of cooling said workpiece with reduction in the pressure in the interior of said high pressure vessel includes a step of supplying liquefied gas in liquid form into said high pressure vessel at a time when the pressure in the interior of said high pressure vessel is less than said high pressure and the temperature of the interior of said high pressure vessel is less than said high temperature and greater than room temperature, wherein the liquefied gas is a gas at near room temperature and pressure, whereby the workpiece is cooled by the heat of vaporization of the liquefied gas supplied in liquid form.