Austenitic stainless steel pipe piece elbow local solid solution treatment method and device

A solution treatment technology for austenitic stainless steel, applied in heat treatment furnaces, heat treatment equipment, furnaces, etc., can solve problems such as high cost of flaw detection, increased sensitivity to stress corrosion, overheating, etc., to avoid coarse tissue, eliminate residual stress, The effect of simple device structure

Active Publication Date: 2018-06-29
HANGZHOU HANGGUO INDUSTRIAL BOILER CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In the boiler industry, there are a large number of U-shaped elbows at both ends of the tube sheet and tube screen. The quality of the U-shaped elbows is related to the normal operation of the entire boiler. At present, the treatment method for U-shaped elbows is mainly solid solution treatment. The treatment is specifically divided into furnace heating treatment, high frequency induction treatment, and electric heating treatment. At present, the treatment method for U-shaped elbows basically adopts furnace-type heating treatment. This method separately heats several U-shaped elbows. The solid solution treatment in the furnace is done, and then it is butt welded with the straight pipe to form the segment. The advantage of this method is that it can effectively avoid the sensitization temperature zone, but the manufacturing process is complicated, and the segment needs to be manufactured by hand. The cost is high, and the welding deformation of the segment is difficult to control. For high-frequency induction treatment, the investment cost of the device is large, and the clamping accuracy is high during solution treatment. High-frequency heating treatment is prone to the risk of breakdown of the tube. For electric heating treatment, It is designed using the characteristics of high resistivity of stainless steel tubes, but there is

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  • Austenitic stainless steel pipe piece elbow local solid solution treatment method and device
  • Austenitic stainless steel pipe piece elbow local solid solution treatment method and device

Examples

Experimental program
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Effect test

Example Embodiment

[0021] Example 1

[0022] The method for local solid solution treatment of the austenitic stainless steel tube elbow of the present invention includes the following preparation steps:

[0023] Step 1: Bend the stainless steel tube into multiple continuous elbows;

[0024] Step 2: Position and fix the elbow on the stainless steel tube piece to avoid the deformation of the heating elbow, and then simultaneously perform primary heating, secondary heating, and soaking on multiple consecutive elbows, primary heating, secondary heating, and soaking continuous The first stage heating is to quickly heat the tube to 425°C, and the second stage heating is to heat the tube to 1095°C at a rate of 3°C / min, and the holding time is ≥15min;

[0025] Step 3: The insulated stainless steel tube piece is rapidly cooled to room temperature at a rate of 25°C / min to obtain the austenitic stainless steel tube piece after solution treatment. The cooling adopts air cooling, and the blowing direction of the air...

Example Embodiment

[0026] Example 2

[0027] The method for local solid solution treatment of the austenitic stainless steel tube elbow of the present invention includes the following preparation steps:

[0028] Step 1: Bend the stainless steel tube into multiple continuous elbows;

[0029] Step 2: Position and fix the elbow on the stainless steel tube piece to avoid the deformation of the heating elbow, and then simultaneously perform primary heating, secondary heating, and soaking on multiple consecutive elbows, primary heating, secondary heating, and soaking continuous And heat preservation after soaking; the first-stage heating is to quickly heat the tube sheet to 425°C, and the second-stage heating is to heat the tube sheet to 1122°C at a rate of 3.5°C / min, and the heat preservation is ≥15min;

[0030] Step 3: The insulated stainless steel tube piece is rapidly cooled to room temperature at a rate of 30°C / min to obtain the austenitic stainless steel tube piece after solution treatment. The cooling ...

Example Embodiment

[0031] Example 3

[0032] The method for local solid solution treatment of the austenitic stainless steel tube elbow of the present invention includes the following preparation steps:

[0033] Step 1: Bend the stainless steel tube into multiple continuous elbows;

[0034] Step 2: Position and fix the elbow on the stainless steel tube piece to avoid the deformation of the heating elbow, and then simultaneously perform primary heating, secondary heating, and soaking on multiple consecutive elbows, primary heating, secondary heating, and soaking continuous And heat preservation after soaking; the first stage heating is to quickly heat the tube sheet to 425°C, and the second stage heating is to heat to 1150°C at a rate of 4°C / min, and the heat preservation is ≥15min;

[0035] Step 3: Quickly cool the insulated stainless steel tube piece to room temperature at a rate of 35°C / min to obtain the austenitic stainless steel tube piece after solution treatment. The cooling adopts air cooling, an...

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Abstract

The invention discloses an austenitic stainless steel pipe piece elbow local solid solution treatment method and device. The treatment method is characterized in that a hydraulic manual flatcar is used for feeding a stainless steel pipe piece elbow into an electric heating furnace for heating, homogenizing and heat preservation, the stainless steel pipe piece is quickly far away from the electricheating furnace through the hydraulic manual flatcar after heat preservation, and rapid cooling is achieved through air blowing of a cooling fan. According to the austenitic stainless steel pipe pieceelbow local solid solution treatment method, the deformation temperature and the deformation amount are controlled, so that austenitic stainless steel is uniformly recrystallized, residual stress generated in cold working of a stainless steel pipe is eliminated, and elbow fracture due to stress corrosion and intergranular corrosion is prevented; control is simple, the working procedures are short, and grain refinement efficiency can be greatly improved; and an elbow is continuously bent on one pipe piece, and the elbow on the pip piece is subjected to solid solution treatment at the same time, so that the problems the working amount is large, the flaw detection cost is high and welding deformation is difficult to control due to the fact that the elbow is independently subjected to solid solution and then is welded with the pipe piece are solved.

Description

technical field [0001] The invention relates to a solid solution treatment method and a device thereof, more specifically, to a local solution treatment method and a device for an austenitic stainless steel tube elbow. Background technique [0002] In the boiler industry, there are a large number of U-shaped elbows at both ends of the tube sheet and tube screen. The quality of the U-shaped elbows is related to the normal operation of the entire boiler. At present, the treatment method for U-shaped elbows is mainly solid solution treatment. The treatment is specifically divided into furnace heating treatment, high frequency induction treatment, and electric heating treatment. At present, the treatment method for U-shaped elbows basically adopts furnace-type heating treatment. This method separately heats several U-shaped elbows. The solid solution treatment in the furnace is done, and then it is butt welded with the straight pipe to form the segment. The advantage of this met...

Claims

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Application Information

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IPC IPC(8): C21D9/08
Inventor 敖玉华金海龙丁海云李文国
Owner HANGZHOU HANGGUO INDUSTRIAL BOILER CO LTD
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