Electric heating – Metal heating – By arc
Reexamination Certificate
1999-09-08
2001-01-30
Shaw, Clifford C. (Department: 1725)
Electric heating
Metal heating
By arc
Reexamination Certificate
active
06180918
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the field of welding, in particular to a method for making welded joints of maraging steel constructions, and can find application in the manufacturing of, for example, high-pressure pipelines operating at cryogenic temperatures that are mainly used for generator units of rocket engines.
BACKGROUND OF THE INVENTION
A method of gas-shielded welding is known, which is used for protecting melted metal of a weld against the unfavorable effect of atmospheric air (I.I. Gorev “Basics of Producing Liquid-Propellant Rocket Engines,” Moscow, 1969, page 61).
It is known that welding maraging steels and alloys with a high volumetric effect of polymorphic transformation requires that a number of measures be taken to prevent cracking of welded joints, loss of material strength, etc., which measures are, for example, assembling with tack welds and filling the grooves by multiple-run welding (“Welding Manual,” edited by N. A. Akulov, Mashinostroenie publishing house, 1971, v. 4, pp. 3-11, 46-84, 93-127).
A method is known for making a welded joint of constructions, including grooving edges of parts for welding, thus forming a Y-shaped form when the edges of the parts are put together, filling the grooves by electric arc gas-shielded welding (USSR Inventor's Certificate No. 5852927, B 23 K 9/02, published 1977). However, grooving the edges of the part for welding with only a Y-shaped form does not make it possible to obtain a highquality connection, especially in the case of parts made of maraging steels.
SUMMARY OF THE INVENTION
The object of the present invention is to increase the quality of a welded joint of parts that are made of maraging steel.
The technical result that may be achieved upon use of the present invention is to obtain a welded joint, when welding parts made of maraging steel, that has high-strength properties without cracks.
In order to achieve the stated object in a method for making a welded joint, which includes the steps of grooving edges of parts for welding, assembling the joint to be welded with tack welds and filling the grooves by multiple-run welding, the edges during the grooving being made Y-shaped and a shrink groove being made in a weld root, the tack welds are made by manual argon-arc welding with a chromium-plated filling wire and direct polarity current, the first run when filling the grooves is made by argon-arc welding using a tungsten electrode with the chromium-plated filling wire and direct polarity current, the second and subsequent, except for the last, runs by automatic helium arc welding with reverse polarity current, the last run by automatic gas-shielded arc welding using a mixture of 50% argon and 50% carbon dioxide as the shielding gas with reverse polarity current, with the attainment of a strengthened weld seam. After each run the weld seam is scraped.
REFERENCES:
patent: 5227609 (1993-07-01), Simon et al.
patent: 6-7934 (1999-01-01), None
patent: 585927 (1977-12-01), None
I.I. Gorev, “Liquid-Propellant rocket Engine Production Basis”, “Mashinostroenie” p. 61, Moscow 1969.
N.A. Akulov, “Welding Manual”, “Mashinostroenie”, vol. 4, p. 8, Moscow 1971.
Derkach Gennady Grigorievich
Grigoriev Anatoly Ivanovich
Loginov Anatoly Lukich
Movchan Jury Vasilievich
Semenov Viktor Nikonorovich
Christie Parker & Hale LLP
Otkrytoe Aktsionernoe Obschestvo "Nauchno-Proizvodstvennoe Obied
Shaw Clifford C.
LandOfFree
Method for making a welded joint 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 making a welded joint, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for making a welded joint will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2440677