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Functionally graded compositional control methods to eliminate dissimilar metal welds (dmws) during manufacture of integral headers

A technology for headers and pipe sections, which is applied in the field of manufacturing header components and can solve problems such as damage

Inactive Publication Date: 2013-03-13
ELECTRIC POWER RES INST INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the stub is close to the header, improper PWHT can cause damage to the stub or the header itself

Method used

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  • Functionally graded compositional control methods to eliminate dissimilar metal welds (dmws) during manufacture of integral headers
  • Functionally graded compositional control methods to eliminate dissimilar metal welds (dmws) during manufacture of integral headers

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Embodiment Construction

[0013] Referring to the drawings, a header assembly formed in accordance with an embodiment of the present invention is shown in FIG. 1 and indicated generally at 10 .

[0014] The present invention utilizes entirely new manufacturing techniques to completely eliminate the need for DMW in header assemblies. The fabrication method utilizes functionally graded compositional control via powder metallurgy and hot isostatic pressing (PM / HIP) to produce a smooth compositional transition from short tube alloys to boiler tube alloys. In this method, the entire header assembly 10 including the stub tube 12 is fabricated using PM / HIP. However, the novelty of the method is that the final 1-2 inches of the tube 12 are fabricated with a functionally graded composition such that the composition changes from low alloy steel (or CSEF steel) section 13 to austenitic stainless steel section 15 using transition section 14 Variation, the transition section is formed by a series of incremental ap...

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PUM

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Abstract

A method of manufacturing a header assembly having a header section and a tube section includes the steps of providing a reverse mold of the header assembly, forming the header section by filling a header section of the reverse mold with an atomized low alloy steel powder, and forming the tube section. The tube section is formed by filling a first portion of a tube section with an atomized low alloy steel powder, forming a transition region by filling a second portion of the tube section with a series of atomized steel powders incrementally from a low alloy steel to an austenitic stainless steel, and filling a third portion of the tube section with an atomized austenitic stainless steel powder. The method further includes the step of consolidating and melting the atomized powders in a high temperature, high pressure atmosphere.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of Provisional Application No. 61 / 489,507, filed May 24, 2011. technical field [0003] The present application relates to a method of manufacturing a header assembly that avoids DMW and eliminates the need for post-weld heat treatment. Background technique [0004] Many fossil fuel power plants are built for continuous baseload operation and are now beginning to understand meaningful cycle operation. Significant strain on components such as headers and high temperature piping is often associated with cyclic practices that often lead to component degradation, cracking, and eventual failure of the component. Additionally, cyclic operation can result in thermal gradients at various locations along the header length that can lead to overheating and damage at these locations. When damage is encountered, utilities are often faced with the dilemma of replacing the entire header. [000...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F5/12
CPCF22B37/22B22F7/06F22B37/225B22F5/106B22F2999/00B22F3/15B22F9/082F28F21/08C22C33/0285B22F2207/01
Inventor D.W.甘地J.辛格尔德克
Owner ELECTRIC POWER RES INST INC