Metal fusion bonding – Process – Plural diverse bonding
Reexamination Certificate
1999-09-13
2001-10-30
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Plural diverse bonding
C228S112100, C228S248100, C219S121640
Reexamination Certificate
active
06308882
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the welding of steel to ductile iron. More particularly, the invention relates to formation of an interface between a steel component and a ductile cast iron component by means of arc, laser, and/or friction welding.
BACKGROUND OF THE INVENTION
Creating a joint or weld between materials having dissimilar thermal expansion and contraction characteristics is a long-standing problem. While desirable, it has been a challenge to unite such materials by means of a bond or weld that possesses inherent physical strength that is equal to or greater than that of the materials being welded. In particular, problems arise when dissimilar metals contract at different rates upon weld completion. The variation in the contraction rates of the metals causes internal stresses, resulting in cracking or weakening of the structure. The problem of varying contraction rates is particularly acute when joining steel and ductile iron.
Moreover, a major technical challenge concerns preventing the formation of cracks due to residual stresses surrounding a welded joint through component use long after a weld is created. When steel and ductile iron are involved, the welded structure has a large heat affected zone that surrounds the joint, as well as a tendency to become brittle around the joint due to carbon transfer from the steel into the iron matrix. Additionally, when a NiRod 55 is used to join ductile iron to steel, as is the current practice, some crevice corrosion eventually appears in the region surrounding the joint. Accordingly, it is desirable to provide a robust, rapid, and reliable process for joining steel with ductile iron, where the resulting joint has a minimal heat affected zone, maximum fatigue strength, and high corrosion resistance.
SUMMARY OF THE INVENTION
The invention includes a method for joining ductile iron with steel. First, a metallic material is deposited between a first ductile iron component and a second steel component. Then an interface material is formed that includes the metallic material by welding the first and second components to the metallic material. The metallic material preferably includes nickel at a concentration greater than or equal to about seventy percent. When nickel is used, it may be applied in the form of a self-fluxing material of about seventy percent nickel. Preferably, however, an exothermic powder is sprayed to the joint area, where the powder includes about ninety-five percent nickel and about five percent aluminum. In any event, the resulting interface material is a weld bead zone that preferably includes nickel at a concentration ranging from about twenty-two percent to about thirty-two percent, and most preferably between about thirty percent and about thirty-two percent.
The welding step of the present invention preferably includes the use of laser energy to localize fusion of the components and the metallic material. The laser energy can be applied in a spiral to form the bead zone, resulting in a stronger overall weld. Alternatively, a friction weld may be used to combine the components. The friction weld may be used alone or may be followed by either arc welding or laser welding.
As one example of the first invention, the first component is a ductile iron steering yoke, and the second component is a steel tube. As a second example, the first component and said second component are combined to form an automobile axle.
REFERENCES:
patent: 3449545 (1969-06-01), Petitt
patent: 3778588 (1973-12-01), Bishel
patent: 3798011 (1974-03-01), Sharp, Jr.
patent: 4391636 (1983-07-01), Windish
patent: 4535793 (1985-08-01), Olson et al.
patent: 4726854 (1988-02-01), Olson et al.
patent: 4794685 (1989-01-01), Hillier
patent: 4817859 (1989-04-01), Bretitenmoser et al.
patent: 4959518 (1990-09-01), Reynolds, Jr.
patent: 5303985 (1994-04-01), Barnholt et al.
patent: 5422071 (1995-06-01), Kiser
patent: 5678753 (1997-10-01), Stauder
patent: 5902498 (1999-05-01), Mistry et al.
patent: 359058318A (1984-04-01), None
Duggan James Andrew
Fett Gregory Allen
Mnushkin Oscar
Shuster Mark
Dana Corporation
Dunn Tom
Rader & Fishman & Grauer, PLLC
Stoner Kiley
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