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A preventive method for reheating cracks in pipe seat fillet welds

A technology of reheat cracks and prevention methods, applied in welding equipment, arc welding equipment, manufacturing tools, etc., can solve the problems of inability to effectively prevent reheat cracks, waste, and product scrapping of thick-walled fillet welds, and solve the problem of tube sockets. Fillet weld reheat crack, reduce economic loss, ensure production cycle and quality effect

Active Publication Date: 2015-08-19
DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for header products with cracks found, since the material and structure cannot be changed, preventive measures can only be considered from the process
Theoretical analysis and practical experience show that technological factors such as welding method, welding material, preheating and postheating, welding specifications and heat treatment process have a great influence on reheat cracking. According to the above aspects and combined with the actual situation of the product, the prevention and control measures, but the rework results of cracked products show that these traditional reheat crack prevention measures and means cannot effectively prevent reheat cracks in the fillet welds of thick-walled 12Cr1MoV material header headers. waste of

Method used

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  • A preventive method for reheating cracks in pipe seat fillet welds
  • A preventive method for reheating cracks in pipe seat fillet welds
  • A preventive method for reheating cracks in pipe seat fillet welds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Example 1: Application example when the outer diameter of the pipe seat is less than or equal to 76mm.

[0057] The inlet header of a high-temperature superheater in a certain project, the material of the header body is 12Cr1MoVG, and the specification is φ635×118mm. There are 384 pipe sockets with pipe joints, the material is 12Cr1MoVG, and the specification is φ57×8mm.

[0058] The welding process of the pipe seat fillet weld is as follows:

[0059] (1) Install and weld the fillet weld of the pipe seat according to the traditional process and requirements; the specific steps are as follows:

[0060] 1) Clean the welding area and the surrounding 20mm area to show a metallic luster;

[0061] 2) Preheat the welding area and the surrounding 400mm range to 200-250°C, and ensure that the interlayer temperature is 200-350°C during the welding process;

[0062] 3) if figure 1 As shown, the electrode arc welding uses the electrode with the brand name E5515-B2-V. The weldi...

Embodiment 2

[0071] Example 2 : An application example when the outer diameter of the pipe seat is greater than 76mm.

[0072] A certain engineering screen passes through an imported mixed header. The body of the header is made of 12Cr1MoVG with a specification of φ571.5×95mm. There are 10 pipe sockets with a material of 12Cr1MoVG and a specification of φ325×70mm arranged on the cylinder.

[0073] The welding process of the pipe seat fillet weld is as follows:

[0074] (1) Install and weld the fillet weld of the pipe seat according to the normal process and requirements, the specific steps are as follows:

[0075] 1) Clean the welding area and the surrounding 20mm area to show a metallic luster;

[0076] 2) Preheat the welding area and the surrounding 400mm range to 200-250°C, and ensure that the interlayer temperature is 200-350°C during the welding process;

[0077] 3) if Figure 4 As shown, manual tungsten argon arc welding is used to make the base, and the welding material grade s...

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Abstract

The invention discloses a tube socket fillet weld reheat crack prevention method which comprises the following steps: first step, installing and welding a tube socket fillet weld; second step, grinding and cleaning the tube socket fillet weld and figuring weld toe; third step, welding a pressure weld pass of the weld toe of the tube socket fillet weld, wherein the welding method of the pressure weld pass is manual tungsten electrode argon-arc welding or welding rod electric-arc welding; fourth step, grinding or machining to eliminate the pressure weld pass of the weld toe, and enabling weld metal and a tube body to smoothly transit; fifth step, grinding and cleaning the test surface of the tube socket fillet weld, and carrying out a 100% nondestructive test; sixth step, after the100% nondestructive test is qualified, carrying out a post-weld heat treatment; seventh step, grinding or polishing the tube socket fillet weld and carrying out a 100% nondestructive review. The tube socket fillet weld reheat crack prevention method is simple in whole technical process, convenient to produce and carry out and good in application effect. The socket fillet weld reheat crack prevention method effectively solves the problem of thick-wall 12 Cr1MoV header tube socket fillet weld reheat crack, ensures production cycles and quality of products and reduces economic losses.

Description

technical field [0001] The invention relates to a method for preventing reheating cracks in fillet welds of pipe seats, in particular to a method for preventing reheating cracks in the fillet welds of boilers and pressure vessels and other products, and belongs to the field of welding technology. Background technique [0002] Boiler drums, headers, pressure vessels and other products have a structural feature that a large number of tube sockets with different diameters and wall thicknesses are arranged on the cylinder body, and these tube sockets and the cylinder body are all connected by welding. Due to the large diameter of the cylinder, the large number of pipe seats, and the thick wall thickness, the degree of restraint during welding is large, and the residual stress after welding is relatively large. At the same time, since the weld toe of the fillet weld between the pipe seat and the cylinder is prone to stress concentration, if the control is not proper, various weld...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K9/167B23K9/00B23K9/235
Inventor 杨要武罗永飞张玮王林森刘洪伟
Owner DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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