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US 4,376,662 AGranted
Methods for fabricating metallic workpieces
AssigneeChem-tronics, Inc.
InventorDaniel J. Brimm
Life of this patent
Estimating the term…
Abstract
Methods for fabricating metallic components in which expansion of a mandrel and changes that take place in the workpiece material during precipitation hardening--phase changes, volume contraction, and increased ductility--are utilized to size the component to a selected diameter and to stabilize the component at that diameter. Mandrels for such methods.
Claims16
A method of fabricating a tubular component of selected dimension and physical properties which comprises the steps of:
- providing a workpiece which has a cylindrical configuration and is fabricated of a precipitation hardening alloy that undergoes a volume change and a change in crystalline structure during hardening and which retains a large part of its strength at the temperature required for precipitation hardening;
- inserting into the workpiece thus formed a mandrel fabricated of a heat resistant alloy having a higher strength and higher coefficient of expansion than the material of which the workpiece is formed;
- and then precisely sizing said workpiece by heating the resulting assembly at a sufficiently high temperature and for a sufficiently long time to first expand the workpiece to the wanted final dimension by expansion of the mandrel and plastic flow of the workpiece material and to then dimensionally stabilize said workpiece at said final dimension by effecting a phase change in the material of which said workpiece is fabricated that hardens said workpiece material and thereby prevents further changes in the dimensions of said material.
A method of fabricating a tubular component of selected dimension, said method comprising the steps of:
- forming a material which undergoes a volume contraction upon heating into a workpiece of cylindrical configuration;
- inserting into the workpiece thus formed a mandrel fabricated of a heat resistant alloy having a higher strength and higher coefficient of expansion than the material of which the workpiece is formed;
- and then precisely sizing said workpiece by heating the resulting assembly to a temperature at which the workpiece will be expanded by expansion of said mandrel to the wanted final dimension and will undergo said volume contraction and a metallurgical phase change that will cause said workpiece to take a permanent set at said final dimension.
Dependencies are inferred from the claim text.