A submerged laser beam irradiation equipment provides a high quality submerged laser beam processing of a submerged workpiece using only a small amount of a gas. The submerged laser beam irradiation equipment has: a focus lens for focusing a laser beam; a mirror tube which houses the lens; a first nozzle operating to cover the front end of the mirror tube in an irradiating direction of the laser beam; a skirt portion provided at the front end of the first nozzle for preventing water intrusion thereinto; and a shutter mechanism operable to open and close and provided between said skirt portion and said mirror tube for preventing water intrusion into said mirror tube.

Submerged laser beam irradiation equipment

A method of forming a stable welded joint between low alloy steels and austenitic stainless alloy steels which is characterized by increased resistance to chemical corrosion and mechanical stress and which has a greatly extended service lifetime. The method comprises forming a deposit of a low alloy steel containing niobium onto a portion of low alloy steel to be welded; heating the deposit to a first temperature at which all carbides present therein have dissolved; quenching the deposit and forming a solid solution of the elements of the dissolved carbides; and reheating the deposit for a time period and at a second temperature sufficient to form niobium carbides therein containing substantially all of the carbon present in the deposit. The austenitic stainless steel portion is welded to the deposit using a substantially nonferrous nickel-based alloy as the weld filler material, thereby joining the low alloy steel portion to the austenitic stainless steel portion.

Forming stable welded joints between dissimilar metals

In diffusion bonding a metal pipe 112 e and a metal pipe 114 e via a bonded interface 116 e formed at the end parts, a portion that is inclined with respect to the radial direction of metal pipes 112 e and 114 e is provided at least at part of bonded interface 116. In this case, the inclination angle φ of bonded interface 116 e and the tip angle 2θ of a pipe expansion tool 130 are preferably in the relationship, 0<φ≦θ+60°. In performing pipe expansion of such a metal pipe bonded body 110 e, the pipe expansion tool 130 is moved from the metal pipe 112 e, at which the inclined portion of junction face 116 e is formed to have a protruding shape, towards the metal pipe 114 e, at which the inclined portion of junction face 116 e is formed to have a recessed shape. Furthermore, the inner diameter at the vicinity of the junction face of the metal pipe junction may be made larger than the inner diameter at positions away from the junction face.

Metal-pipe bonded body, pipe expansion method of metal-pipe bonded body, and method for inspecting metal-pipe bonded body

The invention relates to a hybrid laser/arc-welding method using an electric arc and a laser beam that are combined together within a single welding melt to which molten metal is supplied by melting a filler wire, wherein the welding melt is provided on at least one steel part including an aluminum surface coating, and a protective gas is used, characterized in that the filler wire contains at least 3 wt % of one or more gammagenic elements, in particular the gammagenic elements selected from C, Mn, Ni and N, and the protective gas consists of helium and/or argon with the addition of at least 10 vol % of nitrogen or oxygen. The method of the invention is particularly suitable for welding end-welded flanks used in the field of manufacturing automobiles or for tube welding.

Hybrid arc/laser-welding method for aluminized steel parts using gammagenic elements and a gas containing less than 10 % of nitrogen or oxygen

A laser maintaining and repairing apparatus including a laser oscillator 7, beam guiding apparatus 8 connected to guide a laser beam of the laser oscillator 7, and emitting head 12 for converging the laser beam from the beam guiding apparatus 8 and emitting the beam to a portion to be processed. The beam guiding apparatus 8 includes liquid-tight tubular beam guiding members 9a to 9h. The beam guiding members 9a to 9h are provided with reflecting members 13a, 13b and at least one of mechanisms 10a, 10b and 11a, 11b for providing horizontal turning, horizontal extending, vertical turning and vertical extending operations at the beam guiding members 9a to 9h. With the laser maintaining and repairing apparatus of the noted structure, a laser beam of high energy density can be utilized and processing by the laser beam can be facilitated or the applying range can be increased.

Laser maintaining and repairing apparatus

PURPOSE: To provide a means of forming a structure low in high temp. crack sensitivity at the time of surface treatment and having a surface layer good in corrosion resistance after the execution of the heat treatment and forming the surface treated layer. CONSTITUTION: A structure constituted of an austenitic stainless steel whose surface part is formed of an upper part layer 6 having an austenite single phase structure and a lower part layer 5 having a structure solidified by primary crystal ferrite and the same surface layer are formed. Thus, the structure having the surface layer free from the generation of deterioration in corrosion resistance caused by low temp. sensitization or the like can be produced, and the generation of defects caused by solidifying cracks and high temp. cracks can be prevented at the time of forming the surface lager.

Formation of structure having surface treated layer and surface treated layer

PURPOSE: To improve the erosion resistance of deposited metal by the captioned electrode obtainable by incorporating the specific composition which contains C, Si, Mn, Ni, Cr, Mo and the rest composed of iron and unavoidable impurities. CONSTITUTION: This stainless steel electrode contains C; 0.07W0.12%, Si; 0.4W 0.6%, Mn; 8W12%, Ni; 3W4.5%, Cr; 13W15%, Mo; 0.1W0.5% and the rest composed of Fe and unavoidable impurities. This welding material is contained in at least one of the core wire and covering. With this electrode, the structure of the deposited metal perfectly becomes austenite or the mixture structure of austenite and martensite as welded. Particularly in the latter mixed structure, the superior erosion resistance is obtainable. COPYRIGHT: (C)1980,JPO&Japio

Stainless steel electrode

PURPOSE:To weld a steel material to be welded by a welding material having a strength lower than the strength of said steel undergoing restraint by welding, to cool the same, and thereafter to heat the welded part and to subject the welded parts to aging thereby to increase the strength of the soft welding joint more than the strength of the material to be welded. CONSTITUTION:A steel material to be welded such as a structure steel or the like is welded by a welding material having a strength lower than that of the steel material. In this case, welding is carried out preferably by use of a shield gas prepared by mixing 0.2 to 5% by volume of a nitrogen gas into a gas consisting more than a member selected from the group consisting of argon, helium and a carbonic acid gas. Then, the welded steel is cooled, and thereafter the welded part is heated and held at a temperature in the range of from 200 to 300 deg.C and then subjected to aging.

Steel welding method

PURPOSE:To produce a titled joint which breaks at base metals without breaking at weld metal by using a material of which the tensile strength of deposited metal is lower by a specific rate than that of base metals for the base metals of which the hardness in weld heat affected zone is higher than that of blank material parts. CONSTITUTION:A low alloy steel plate of about 60-70kg/mm. tensile strength is desirable as a material of which the weld heat affected zone exhibits hardness higher than that of blank material parts despite the receipt of tempering effect accompanied with multilayer welding. In the case in which the heat affected zone has hardness higher than that of the blank material parts, the plastic restraining phenomenon occuring in weld metal during acting of the tensile force in the direction perpendicular to the weld line is accelerated effectively by the adjacency of the heat affected zone harder than the blank material parts of base metals to the weld metal. Hence, althrough this depends upon the tensile strength of the deposited metal as well, the joint will break at the base metals without breaking at the weld metal. However, the use of a welding material of which the tensile strength of deposited metal is >=82% that of base metals and is smaller than that of base metals in the state that the reinforcement of weld is left is a condition.

Production of welded joint in hydraulic turbine casing

PURPOSE: To provide an underwater laser beam machining equipment which machines an underwater structure with high efficiency and with high quality by providing a partition wall between a chamber with one end opened to an external environment and a chamber housing a laser torch, and opening/closing the partition. CONSTITUTION: A chamber 2 is closely attached to the surface of a structure 1. The part of the chamber 2 in contact with the surface of the structure is closely attached and prevents water from entering from the periphery. Then, the water in the chamber in contact with the surface of the structure is discharged by a water discharging mechanism 16 and a gas injecting mechanism 15 to realize the gaseous atmosphere. A shield plate 12 is opened by a shield plate driving mechanism to integrate the chamber. Access is made to a laser torch 6. The position of the laser torch 6 and the distance from the laser torch to the structure surface are set in an appropriate condition by a laser beam irradiating part monitoring mechanism 19 or a distance monitoring mechanism 18. The structure surface is irradiated with the laser beam emitted from a laser beam oscillator and transmitted through the optical fiber 10.

Konuma Tsutomu

Papers

Formation of structure having surface treated layer and surface treated layer

Stainless steel electrode

Steel welding method

Production of welded joint in hydraulic turbine casing

Underwater laser beam machining equipment and underwater execution method using the equipment