Government of the United States of America, As Represented by the Secretary of Commerce

Other

National Institute of Standards and Technology

Thomas A Siewert

Dale W Fitting

William P Dube

Christopher N McCowan

Richard D Albert

R Bruce Madigan

Timothy P Quinn

The present invention relates to x-ray diffraction measurement by using moving x-ray source x-ray diffraction. The invention comprises a raster-scanned x-ray source, a specimen, a collimator, and a detector. The x-ray source is electronically scanned which allows a complete image of the x-ray diffraction characteristics of the specimen to be produced. The specimen is placed remote from the x-ray source and the detector. The collimator is located directly in front of the detector. The x-rays are diffracted by the specimen at certain angles, which cause them to travel through the collimator and to the detector. The detector may be placed in any radial location relative to the specimen in order to take the necessary measurements. The detector can detect the intensity and/or the wavelength of the diffracted x-rays. All information needed to solve the Bragg equation as well as the Laue equations is available. The x-ray source may be scanned electronically or mechanically. The present invention is used to perform texture analysis and phase identification.

Method and apparatus for diffraction measurement using a scanning x-ray source

An alloy comprising nickel, chromium, molybdenum, manganese, nitrogen and on in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in a concentration of from about 0.1 to about 0.2% of the alloy in weight percent. The weld metals prepared from the alloys of the present invention possess superior properties as compared to other stainless steels. These properties include inter alia a superior tearing modulus, fracture toughness, and yield strength, even at cryogenic temperatures. The present invention further provides a method for welding a metal part which is intended for exposure to cryogenic temperatures comprising welding the metal part using a welding electrode comprising nickel, chromium, molybdenum, manganese, nitrogen and iron in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in the electrode in a concentration of from about 0.1 to about 0.2% of the electrode in weight percent. Preferably, the welding comprises gas metal arc welding, wherein shielding gas used during welding contains no more than about 2% oxygen by volume.

Method for welding cryogenic alloys

The present invention uses a high energy x-ray, neutron, or gamma source for monitoring the interface between a molten and solidified crystalline phase while in a furnace in a casting process. The radiation can also be used to determine the quality and orientation of the crystals in the crystalline phase. The invention uses the distinctive diffraction patterns produced by crystalline and amorphous phases to locate the interface.

Apparatus and method for monitoring casting process

A method and apparatus for preventing catastrophic melting of the contact be in continuously-fed consumable electrode arc welding due to wire feed interruptions by monitoring the movement of the wire electrode with a high frequency sensor such as all optical encoder having a resolution on the order of &lt;0.1 second and switching off the power to the welding apparatus if the wire electrode speed falls below a predetermined threshold.

Prevention of contact tube melting in arc welding

An alloy comprising nickel, chromium, molybdenum, manganese, nitrogen and iron in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in a concentration of from about 0.1 to about 0.2% of the alloy in weight percent. The weld metals prepared from the alloys of the present invention possess superior properties as compared to other stainless steels. These properties include inter alia a superior tearing modulus, fracture toughness, and yield strength, even at cryogenic temperatures. The present invention further provides a method for welding a metal part which is intended for exposure to cryogenic temperatures comprising welding the metal part using a welding electrode comprising nickel, chromium, molybdenum, manganese, nitrogen and iron in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in the electrode in a concentration of from about 0.1 to about 0.2% of the electrode in weight percent. Preferably, the welding comprises gas metal arc welding, wherein shielding gas used during welding contains no more than about 2% oxygen by volume.

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Boulder, CO, United States of America

Thomas A Siewert