The present invention relates to a method of providing a spray formed composite article. The method comprises providing a first article. The first article is a spray formed article. A second article is located adjacent the first article. Metallic particles are sprayed onto the articles and allowed to form a metal deposit that extends between and connects the first and second articles.

Method of spray joining articles

A process for buttwelding metal workpieces (12) having bevelled joint preparations using an automatic GTAW welder (20) using filler wire (32) includes preparing the bevelled workpieces (12) with bevelled joint areas having minimal land thickness at the root extremities; placing the prepared workpiece joint sections together with an open gap between their adjacent root extremities, the gap having a minimum dimension that avoids harmful compression stress between the workpieces due to weld shrinkage and a maximum dimension that avoids filler wire penetration of the gap; fusion welding the open root area of the adjacent workpieces (12) with a root pass weld using an automatic GTAW welder (20) supplied with filler wire (32) and a shield gas including 1 to 10 % hydrogen and the balance inert gas; and then promptly overlaying the root pass weld with at least one additional filler weld pass using an automatic GTAW welder (20) supplied with filler wire (32) and hydrogen-free shield gas.

Method of welding

A welded structure and a method for making same wherein a plurality of weld metals, such as martensitic steel and austenitic steel, differing in coefficient of thermal expansion from each other are deposited in a plurality of layers thicknesswise of the welded structure in a gap defined by structural members to be welded in such a manner that a layer of the weld metal of higher coefficient of thermal expansion is covered by a layer of the weld metal of lower coefficient of thermal expansion in a weld formed, to improve brittle fracture strength, fatigue strength and stress corrosion cracking resistance of the weld. By subjecting the welded structure to stress relief annealing treatment, it is possible to produce compressive stress on the surface of the layer of the weld metal of lower coefficient of thermal expansion.

Welded structrue having improved mechanical strength and process for making same

An end portion of each of two parts (10, 11) is machined and the machined end portions of the parts (10, 11) are arranged in facing positions to form a welding bevel (13) extending in a longitudinal direction between the parts (10, 11), whereafter a filler metal is deposited into the welding bevel (13). The welding bevel is a narrow bevel with side walls at an aperture angle of no more than 5° relative to the longitudinal central plane of the bevel (13). A nickel alloy comprising 18-32 % of chromium is deposited into the welding bevel. The method is particularly suitable for joining a pressurised water nuclear reactor vessel tubing and an austenitic stainless steel primary circuit pipe.

Method for joining two parts of different kinds by heterogeneous butt welding, and uses thereof

A method of elctric-arc welding includes the steps of feeding of a main metal-arc electrode (4) into a welding zone (1), the electrode being composed of at least one filler wire, and an additional metal-arc electrode (5) made up of at least one filler wire (6, 7, 8) and being under the same potential as the main metal-arc electrode (4). Control of the welding current, size and shape of the weld seam is carried out by virtue of a total cross-sectional area of the additional metal-arc electrode (5). Then the crater at the end of a weld seam (13) is filled up by consecutively disengaging the feed traverse of the filler wires of the main and additional metal-arc electrodes (4, 5).

Method of electric arc welding

of the Disclosure In a multiple electode gas shielded arc welding method wherein a plurality of electrodes are arranged along the welding seam line of a piece of metal to be welded and the continuous gas shielded arc welding of the piece is accomplished simultaneously by the electrodes, the chemical composition of a mixed shielding gas fed to the electrodes is selected in such a manner that the chemical composition of the shielding gas fed to the leading electrode or electrode group differs relative to that fed to the trailing electrode or electrode group to have a different active gas volume ratio and in this way the chemical composition of the weld metal layers formed by the preceeding and following welding operations are homogenizing to ensure uniformity of the properties at every positions in the weld zone.

Method of multiple electrode gas shielded arc welding

of the Disclosure In a method of multiple electrode gas shielded arc welding wherein a plurality of electrodes are arranged along the welding seam line of a piece of metal to be welded and the continuous gas shielded arc welding of the piece is accomplished simultaneously by the electrodes, the chemical. composition of the electrode wire of the electrode or electrode group for depositing a proceeding layer or layers is selected to differ from that of the electrode wire of another electrode or electrode group for depositing a subsequent layer or layers, whereby the chemical composition of the weld metal made by the preceed-ing welding operation is brought near to that of the weld metal made by the following welding operation and thus the uniform properties are ensured for the welding metals at the respective positions in the weld zone.

Method of multiple gas shielded arc welding

An investigation has been carried out to realize commercial application of welding of 9% Ni steel using ferritic filler metal having chemical composition similar to that of base steel, which was developed by the authors.The weldments having excellent notch impact properties and superior strength were obtained by gas metal arc welding.And the brittle fracture initiation characteristics before general yielding of the weldment was surveyed both experimentally by three kinds of the large scale type tests such as Welded Wide Plate Tension Tests, W-I Type Notched and Welded Wide Plate Tension Test and Deep Notch Test and theoretically based on the fracture mechanics.The safety to brittle fracture before general yielding was confirmed especially at LNG temperature.

Gas Metal Arc Welding of 9% Nickel Steel Using Ferritic Filler Metal Used for Building LNG Transport Tanker

We obtained the following results from fatigue test on the welded joints of HT 80 with the reinforcements removed using the modified Schenck's test pieces.(1) The endurance limits of the welded joints were slightly lower than that of the base metal.(2) Most welded joints failed at the bonded zone or the softened zone in H. A. Z. In the case of the specimens failed at the bonded zone, the fatigue cracks started in the coarse grain zone.(3) The welded joints failed almost at the softened zone when the applied stress was comparatively high and failed slightly more at the bonded zone than the softened zone when the applied stress was near the endurance limit.(4) Considering the result (3), we had investigated the endurance limit (σ) from two points hardness (H) and grain diameter (D) and proposed the following formula, σ=a1H1/√D+b11/√D+a2H+b2, where a1, b1, a2, b2 are the constant values without concerning the material, and we proposed the following values : a1=0.0017, b1=0.54, a2=0.11, b2=3.5.(5) From one more experiment on the grain size dependence of the fatigue strength, we obtained the fact that the effect of the grain size on the fatigue strength decreases with increase of the applied stress.(6) The equation above mentioned shows the endurance limit, but when the applied stress is comparatively higher than the endurance limit, the values 'a1' and 'b1' must be smaller than 0.0017 and 0.54 judging from the result (5). In this case we can see that the fatigue strength of bonded zone is higher than that of the softened zone.

Itaru Watanabe

Papers

Method of multiple electrode gas shielded arc welding

Method of multiple gas shielded arc welding

Gas Metal Arc Welding of 9% Nickel Steel Using Ferritic Filler Metal Used for Building LNG Transport Tanker

Variation of the Positions where the Welded Joints of HT 80 failed in the Fatigue Test

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