Metal treatment – Process of modifying or maintaining internal physical... – Carburizing or nitriding using externally supplied carbon or...
Patent
1996-08-29
1999-03-16
Wyszomierski, George
Metal treatment
Process of modifying or maintaining internal physical...
Carburizing or nitriding using externally supplied carbon or...
148224, 148565, 21912166, 21912168, 21912169, 225 2, B23K 2600
Patent
active
058824383
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a method for the formation of a frangible zone for fracture separation of a part, in particular, connecting rods for internal combustion machines. A frangible zone is produced for the intended triggered fracture having ribs and depressions which are separated, one from the other, and arranged at least partially in the surface of the part along one side of the fracture separation plane.
A method for the formation of stress riser grooves in the fracture plane of a separable part is known through the U.S. Pat. No. 5,208,979. To produce stress riser grooves that are essentially knife-sharp at their bases, grooves having a V-shaped cross section are formed in the part's surface by means of a laser at appropriate locations in or on the part. The depth of the groove is greater than its width. As is known, the hairline cracks that initially form at the beginning of a fracturing process at the bottom of a stress riser groove are of considerable importance for the quality of the fracturing surfaces, said cracks not being deliberately predictable because of the inhomogeneous structure of the part over the length of the stress riser grooves.
This disadvantage should be overcome in accordance with German patent document DE-U 295 19 126 in the case of a formed workpiece, especially a connecting rod with an opening (a bore for a bearing), having diametrically opposed frangible zones. Instead of every continuous, straight line V-groove being produced by a laser in accord with U.S. Pat. No. 5,208,979, a plurality of indentations laid linearly next to each other serve as groove sections. The laser employed for the boring of the groove sections into finger shaped, or cylindrical blind holes, is so far reduced in load capacity by this procedure, that the transformation associated with heat input (Martinsite) in the adjacent areas of the groove sections is exceptionally small. It is a stated goal, to avoid in all cases, a continuous transformation occurring in the ribs which remain between the groove sections, in order that these frangible zones can be machined away following a fracture.
Further, the production of a series of blind holes, in a naturally hardened work piece next to one another by means of a laser for the purpose of engendering a controlled fracture, is also known, as this is described in the American magazine "Mechanical Engineering" in the April issue of 1990 in the article "Detroit looks to lasers" on page 41 in the left column.
The goal of the invention is to form the intended frangible zones in a fracturing plane for the predicted production of a crack, in a part made of ductile metal and divisible by fracturing in such a manner that starting cracks are achieved that are deliberately distributed over the length of the respective frangible zone.
The present invention achieves this goal by a method for the formation of a frangible zone for fracture separation of a part, in particular, connecting rods for internal combustion machines. A frangible zone is produced for the intended triggered fracture having ribs and depressions which are separated, one from the other, and arranged at least partially in the surface of the part along one side of the fracture separation plane. In the part, such as a rod, made of ductile metal, the ribs, at least in their free end sections near to the surface of the part, are penetratively embrittled for making an initial starting crack for triggering the break. This is done by performing a transformation across their cross sections. In the case of a part of ductile metal, the ribs, at least in their free end segments near to the surface of the part, become penetratably embrittled by a material transformation over their cross section, thus making the initial cracking for the triggering of the fracture.
Along with the frangible zones produced in accordance with the invention, contrary to a conventional, continuous groove parting line, or contrary to groove sections of softened material arranged in rows, there arises in
REFERENCES:
patent: 3818577 (1974-06-01), Bailey et al.
patent: 4401477 (1983-08-01), Clauer et al.
patent: 4533400 (1985-08-01), Benedict
patent: 4708752 (1987-11-01), Kar
patent: 4754906 (1988-07-01), Brovold
patent: 4970783 (1990-11-01), Olaniran et al.
patent: 5208979 (1993-05-01), Schmidt
patent: 5413641 (1995-05-01), Coulon
patent: 5626777 (1997-05-01), Hugl et al.
Mechanical Engineering (Apr. 1990) entitled "Detroit Looks to Lasers", pp. 38-45.
Hochsteiner Helmut
Luchner Clemens
Poellath Helmut
Bayerische Motoren Werke Aktiengesellschaft
Wyszomierski George
LandOfFree
Method for the formation of a frangible zone for the fracture se does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the formation of a frangible zone for the fracture se, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the formation of a frangible zone for the fracture se will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-813554