Provided is a novel method for improving fatigue strength, which is applicable to any small portion that is covered with another member. A method for improving fatigue strength according to the present invention includes: disposing an aid (3, 15) to be opposed to an processing object (2A, 2B, 6) on which a fatigue strength improving process is performed, the aid being configured to assist the improving process; and generating sparks between the aid (3, 15) and the processing object (2A, 2B, 6).

Provided is a novel method for improving fatigue strength, which is applicable to any small portion that is covered with another member. A method for improving fatigue strength according to the present invention includes: disposing an aid (3, 15) to be opposed to an processing object (2A, 2B, 6) on which a fatigue strength improving process is performed, the aid being configured to assist the improving process; and generating sparks between the aid (3, 15) and the processing object (2A, 2B, 6).

A method of manufacturing a welded structure of a ferritic heat-resistant steel is provided that prevents Type IV damage and that has good on-site operability without adding a high B concentration. The method includes: the step of preparing a base material including 1.0 to 7.0% Cr, less than 0.005% B and other elements; the step of forming an edge on the base material; a pre-weld heat treatment step in which a region located between a surface of the edge and a position distant from the surface of the edge by a pre-weld heat treatment depth of 10 to 50 mm is heated to a temperature of 950 to 1050 C. and is held at this temperature for 10 to 30 minutes; a welding step in which the edge is welded to form the weld metal; and a post-weld heat treatment step in which a region located between the surface of the edge and a position distant therefrom by a distance not smaller than the pre-weld heat treatment depth and not greater than 100 mm is heated to a temperature of 680 to 750 C. and is held at this temperature for a time period not shorter than 30 minutes and satisfying the following formula, (1):
(Log(t)+10).Math.(T+273)<10539(1).

A method of manufacturing a welded structure of a ferritic heat-resistant steel is provided that prevents Type IV damage and that has good on-site operability without adding a high B concentration. The method includes: the step of preparing a base material including 1.0 to 7.0% Cr, less than 0.005% B and other elements; the step of forming an edge on the base material; a pre-weld heat treatment step in which a region located between a surface of the edge and a position distant from the surface of the edge by a pre-weld heat treatment depth of 10 to 50 mm is heated to a temperature of 950 to 1050 C. and is held at this temperature for 10 to 30 minutes; a welding step in which the edge is welded to form the weld metal; and a post-weld heat treatment step in which a region located between the surface of the edge and a position distant therefrom by a distance not smaller than the pre-weld heat treatment depth and not greater than 100 mm is heated to a temperature of 680 to 750 C. and is held at this temperature for a time period not shorter than 30 minutes and satisfying the following formula, (1):
(Log(t)+10).Math.(T+273)<10539(1).

A heating system includes a power source connected to a heater to heat a workpiece via the heater and a controller. The controller is configured to receive the first temperature measurement signal, the first temperature measurement signal corresponding to a first temperature of the workpiece. The controller is to turn on the power source to activate the heater to heat the workpiece, receive the second temperature measurement signal in response to heating the workpiece, the second temperature measurement signal corresponding to a second temperature of the workpiece. The controller calculates a change in temperature of the workpiece based on the first and second temperatures, and determines a physical characteristic of the workpiece based on the change in temperature.

A heating system includes a power source connected to a heater to heat a workpiece via the heater and a controller. The controller is configured to receive the first temperature measurement signal, the first temperature measurement signal corresponding to a first temperature of the workpiece. The controller is to turn on the power source to activate the heater to heat the workpiece, receive the second temperature measurement signal in response to heating the workpiece, the second temperature measurement signal corresponding to a second temperature of the workpiece. The controller calculates a change in temperature of the workpiece based on the first and second temperatures, and determines a physical characteristic of the workpiece based on the change in temperature.

A joint connection method is provided that is a method for connecting joints that are used for a hydraulic pressure test or the like to a long pipe by using a production facility which includes a conveyance system, a welding apparatus, a winding apparatus and an X-ray inspection apparatus. The joint connection method includes a step of girth welding a first joint to a front end portion of the long pipe by means of the welding apparatus, a step of inspecting a girth weld zone of the first joint by means of the X-ray inspection apparatus, a step of girth welding a second joint to a rear end portion of the long pipe by means of the welding apparatus, and a step of inspecting a girth weld zone of the second joint by means of the X-ray inspection apparatus.

A joint connection method is provided that is a method for connecting joints that are used for a hydraulic pressure test or the like to a long pipe by using a production facility which includes a conveyance system, a welding apparatus, a winding apparatus and an X-ray inspection apparatus. The joint connection method includes a step of girth welding a first joint to a front end portion of the long pipe by means of the welding apparatus, a step of inspecting a girth weld zone of the first joint by means of the X-ray inspection apparatus, a step of girth welding a second joint to a rear end portion of the long pipe by means of the welding apparatus, and a step of inspecting a girth weld zone of the second joint by means of the X-ray inspection apparatus.

A method of manufacturing a metallic part in a weldable material by solid freeform fabrication unrestricted in size and open to the ambient atmosphere. The method comprises generating a computer-generated, three dimensional model of the part, slicing the computer-generated three dimensional model into a set of computer-generated, parallel, sliced layers and then dividing each layer into a set of computer-generated, virtual, one-dimensional pieces and, with reference to layered weld-bead geometry data, forming a computer-generated, direction specific, layered model of the part. The method also comprises uploading the direction specific, layered model of the part into a welding control system able to control the position and activation relative to a support substrate, of an electric arc delivered by a high energy tungsten arc welding torch, a plasma transferred arc welding torch, and/or a gas metal arc welding torch, and a system for feeding a consumable wire placed in an open area build space relevant to the substrate unrestricted in size and open to the ambient atmosphere. The method also comprises directing the welding control system to deposit a sequence of one-dimensional weld beads of the weldable material onto the supporting substrate in a pattern required to form a first layer of the computer-generated, direction specific, layered model of the part, and depositing a second welded layer by sequencing one-dimensional weld beads of the weldable material onto the previous deposited layer in a configuration the same as the second layer of the computer-generated direction specific layered model of the part, and repeating each successive weld bead layer of the computer-generated, direction specific, layered model of the part until the entire part is completed. The method further includes one or both of displacing the atmosphere within the immediate vicinity of the heat source with an inert gas atmosphere which produces a required flow rate, and in which that inert atmosphere contains a maximum oxygen concentration, wherein the inert gas is delivered by an apparatus through a matrix of individual gas diffusers and/or a filter; and engaging an induction heating and closed loop cooling apparatus synergic to a welding control system and pre-heating the substrate material including the deposited weld beads, relevant to the type of weldable material, wherein induction heating and cooling cycles are applied constantly or pulsed from the first layer to the final layer, where optimal heating and/or cooling cycles of the weldable material are relative to the final desired part shape and microstructure.

A method of manufacturing a metallic part in a weldable material by solid freeform fabrication unrestricted in size and open to the ambient atmosphere. The method comprises generating a computer-generated, three dimensional model of the part, slicing the computer-generated three dimensional model into a set of computer-generated, parallel, sliced layers and then dividing each layer into a set of computer-generated, virtual, one-dimensional pieces and, with reference to layered weld-bead geometry data, forming a computer-generated, direction specific, layered model of the part. The method also comprises uploading the direction specific, layered model of the part into a welding control system able to control the position and activation relative to a support substrate, of an electric arc delivered by a high energy tungsten arc welding torch, a plasma transferred arc welding torch, and/or a gas metal arc welding torch, and a system for feeding a consumable wire placed in an open area build space relevant to the substrate unrestricted in size and open to the ambient atmosphere. The method also comprises directing the welding control system to deposit a sequence of one-dimensional weld beads of the weldable material onto the supporting substrate in a pattern required to form a first layer of the computer-generated, direction specific, layered model of the part, and depositing a second welded layer by sequencing one-dimensional weld beads of the weldable material onto the previous deposited layer in a configuration the same as the second layer of the computer-generated direction specific layered model of the part, and repeating each successive weld bead layer of the computer-generated, direction specific, layered model of the part until the entire part is completed. The method further includes one or both of displacing the atmosphere within the immediate vicinity of the heat source with an inert gas atmosphere which produces a required flow rate, and in which that inert atmosphere contains a maximum oxygen concentration, wherein the inert gas is delivered by an apparatus through a matrix of individual gas diffusers and/or a filter; and engaging an induction heating and closed loop cooling apparatus synergic to a welding control system and pre-heating the substrate material including the deposited weld beads, relevant to the type of weldable material, wherein induction heating and cooling cycles are applied constantly or pulsed from the first layer to the final layer, where optimal heating and/or cooling cycles of the weldable material are relative to the final desired part shape and microstructure.