Metal fusion bonding – Process – With measuring – testing – indicating – inspecting – or...
Reexamination Certificate
1999-11-19
2001-02-27
Ryan, Patrick (Department: 1725)
Metal fusion bonding
Process
With measuring, testing, indicating, inspecting, or...
C029S705000, C073S850000
Reexamination Certificate
active
06193133
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for evaluating performance of welded joints.
2. Description of the Prior Art
An evaluation of the performance of welded butt joints has been accomplished by use of standard tensile specimens (ISO or ASTM), rectangular plaques and T-shape elements (ultrasonic welding specimens, American Welding Society G1.2). After welding, the effectiveness of the joints is tested using standard test practices. The use of standard tensile specimens (ISO or ASTM), rectangular plaques and T-shape elements has advantages, among which are the availability of injection-molded plaques, and convenient configuration and size of test specimens for easy machining operations for the specimen preparations. A problem encountered with use of standard tensile specimens (ISO or ASTM), rectangular plaques and T-shape elements is the limitation that these specimens may only be successfully welded using specially prepared, small welding machines. Only one such small size linear vibration welding machine is available commercially at this time. Such a machine, designated Model M-102, is manufactured by Branson Ultrsonic, Germany. When a company is equipped with a mid or large welding machine for welding midsize and large parts, such as lawn mower housings and air intake manifolds, it is very hard to evaluate tensile properties of the joints following the ASTM or ISO procedures. In such circumstances, these specimens are too small for the machine size, and the clamp pressure will be too high. Mechanical performance of thus-welded specimens will often not represent true weld strength property of the material being evaluated.
It would be desirable to provide a method and articles for evaluating welded joints which would overcome the above mentioned shortcomings.
SUMMARY OF THE INVENTION
The invention provides articles and methods for evaluating the performance of welded joints with the influence of design, processing conditions such as welding, molding and the like, and material composition. Advantageously, the invention can be used to perform and evaluate linear vibration, orbital vibration, hot plate, infrared, hot gas, hot gas extrusion welding process, at a variety of bead thicknesses. In practice, two polygon shaped articles having walls of different thicknesses are mated and welded together. Specimens are then cut from this composite part for testing.
More specifically, the invention provides an article for evaluating the performance of welded butt joints and optimizing the design, processing conditions and material composition thereof, comprising: a base plate having a top face and a bottom face; a first polygon shaped welding edge; a second polygon shaped welding edge (hereinafter referred to as “edge”); and a plurality of sets of two parallel walls, each set of walls being provided with a top edge and bottom edge, the top edge and the bottom edge having a predetermined thickness, each wall of a set being oppositely positioned perpendicular to and around the base plate, thereby forming a deep bowl on the top face and a shallow bowl on the bottom face; whereby the top edges form the first polygon shaped edge, and the bottom edges form the second polygon shaped edge.
Preferably, the set of walls has a unique thickness for the top and bottom edges. The plurality of sets of two parallel walls forms an octagon comprised of thermoplastic material. Optionally, the article further comprises a plurality of radial ribs that provide and maintain flexural support for the walls of the deep bowl during welding operations.
The invention also provides a composite welded part for evaluating the performance of thermoplastic welded butt joints and optimizing the design, processing conditions and material composition thereof comprising: a first article and a second article; wherein both the first and second articles comprise a base plate having a top face and a bottom face; a first polygon shaped welding edge; a second polygon shaped welding edge (hereinafter referred to as “edge”); and a plurality of sets of two parallel walls, each set of walls being provided with a top edge and bottom edge, the top edge and the bottom edge having a predetermined thickness, each wall of a set being oppositely positioned perpendicular to and around the base plate, thereby forming a deep bowl on the top face and a shallow bowl on the bottom face; whereby the top edges form the first polygon shaped edge, and the bottom edges form the second polygon shaped edge; and wherein the first article and the second article are mated to each other by welding of their respective polygonal welding edges.
The invention further provides a method for evaluating the strength and life, i.e. creep and fatigue, of welded butt joints, comprising the steps of: selecting a material to be used in forming the butt joints; forming from the material, a first article and a second article, each of the first and second articles having a structure comprising: a base plate having a top face and a bottom face; a first polygon shaped welding edge; a second polygon shaped welding edge (hereinafter referred to as “edge”); and a plurality of sets of two parallel walls, each set of walls being provided with a top edge and bottom edge, the top edge and the bottom edge having a predetermined thickness, each wall of a set being oppositely positioned perpendicular to and around the base plate, thereby forming a deep bowl on the top face and a shallow bowl on the bottom face; whereby the top edges form the first polygon shaped edge, and the bottom edges form the second polygon shaped edge; selecting a first polygon shaped edge of the first article; selecting a first polygon shaped edge of the second article; selecting a set of walls of the first article; selecting a set of walls of the second article; connecting the selected polygon shaped edges and aligning the selected set of walls to mate the first article and the second article together; placing the mated first and second article onto a welding machine; welding the first article to the second article to form a composite part; cutting specimens from the welded selected set of walls of the composite part; and testing the specimens.
The invention represents a significant improvement over previous welding and test systems because it makes possible the evaluation of butt joints for midsize and large parts fabricated in large welding machines. Advantageously, the size and configuration of the article tested is more closely matched with parameters of articles employed in actual manufacturing situations from small to large.
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Kagan Val A.
Lee Chul S.
Allied-Signal Inc.
Criss Roger H.
Edmondson L.
Ryan Patrick
LandOfFree
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