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Manual argon tungsten-arc welding and welding rod electric-arc welding combined welding method of G115 large-diameter pipe

A technology of argon tungsten arc welding and electrode arc welding, applied in arc welding equipment, welding equipment, manufacturing tools, etc., can solve the problems of thermal crack penetration, poor, difficult to guarantee the mechanical properties of G115 large-diameter pipes, etc., and achieve forming The effect of beautiful appearance and excellent mechanical properties

Active Publication Date: 2019-06-11
HARBIN BOILER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems that G115 large-diameter pipes are prone to cold and hot cracks and poor penetration under the existing welding technology, and it is difficult to ensure that G115 large-diameter pipes form welded joints with excellent mechanical properties and beautiful shapes, and provide Welding method combining manual tungsten argon arc welding and electrode arc welding for G115 large diameter pipe

Method used

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  • Manual argon tungsten-arc welding and welding rod electric-arc welding combined welding method of G115 large-diameter pipe
  • Manual argon tungsten-arc welding and welding rod electric-arc welding combined welding method of G115 large-diameter pipe
  • Manual argon tungsten-arc welding and welding rod electric-arc welding combined welding method of G115 large-diameter pipe

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specific Embodiment approach 1

[0027] Specific implementation mode 1: This implementation mode is a welding method combining manual argon tungsten arc welding and electrode arc welding of G115 large-diameter tubes, which is completed according to the following steps:

[0028] 1. Preparation before welding: Prepare the groove of the G115 large-diameter pipe, and then assemble it;

[0029] 2. Welding process: preheat the G115 large-diameter pipe, the first and second layers are manual tungsten argon arc welding, the layer temperature is ≤300 ℃, and the thickness of the deposited metal is 2mm to 3mm; the third layer is arc welding with electrodes. The layer temperature is ≤300℃, the thickness of the deposited metal is 2mm~3mm; the subsequent welding layer adopts electrode arc welding, the layer temperature is ≤300℃, and the thickness of the deposited metal is 3mm~4mm;

[0030] 3. Post-weld heat treatment: After welding, cool the G115 large-diameter pipe to 100°C-150°C, keep it warm for 1h, then raise the tempe...

specific Embodiment approach 2

[0036] Embodiment 2: The difference between this embodiment and Embodiment 1 is that when preparing the groove in step 1, the groove is prepared according to the welding filling amount and side wall fusion, so as to facilitate observation of weld seam and defect grinding. The wall thickness of the pipe is ≤40mm, and the bevel angle on one side is between 10° and 20°; the wall thickness of the pipe is more than 40mm, and the bevel is prepared by changing the angle, and the bevel angle on one side before the angle change is between 10° and 20° After changing the angle, the single-side groove angle is between 5° and 8°.

[0037] Other steps are the same as in the first embodiment.

[0038] Clean the groove of the G115 large-diameter pipe and both sides of the inner and outer walls to remove water, oil and other dirt.

specific Embodiment approach 3

[0039] Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that in the second step, electric heating or flame heating is used for preheating.

[0040] Other steps are the same as those in Embodiment 1 or 2.

[0041] Electric heating is preferred for preheating. If flame heating is used for preheating, the flame must not stay in the same position. At the same time, the flame combustion status should be controlled to prevent G115 from oxidation or carbonization. When electric heating or flame is used to preheat the outer wall, the welding seam is the center, and the heating width is not less than 75mm on both sides of the welding seam.

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Abstract

The invention provides a manual argon tungsten-arc welding and welding rod electric-arc welding combined welding method of a G115 large-diameter pipe, relates to the technical field of pipe welding, and aims at solving the method that a G115 large-diameter pipe is easily subjected to cold and hot racks and poor weld penetration in an existing welding technology and weld joints with high mechanicalperformance and good formation cannot be ensured. The method comprises the steps of 1, preparing before welding, namely, preparing a groove of the G115 large-diameter pipe, and aligning the groove and assembling; 2, welding, namely, preheating the G115 large-diameter pipe; performing manual argon tungsten-arc welding on a first layer and a second layer; and performing electric arc welding on a third layer and the following welding layers through welding bars; and 3, heat treatment after welding, namely, cooling the G115 large-diameter pipe after welding; increasing the temperature; and continuously increasing the temperature. The method is applicable to welding of the G115 large-diameter pipe.

Description

technical field [0001] The invention relates to the technical field of pipe welding. Background technique [0002] G115 material is a newly developed high-temperature martensitic alloy steel. On the basis of SA-335P92 (9Cr2W), the content of W element is increased, and the high-temperature resistant alloying element Co is added. The chemical composition is 9Cr-3W-3CoCuVNbBN. It has higher high-temperature strength and creep performance than SA-335P92, and its thermal fatigue resistance, thermal conductivity and linear expansion coefficient are far superior to austenitic stainless steel. It has become a candidate material for advanced supercritical boilers at 630 °C. Therefore, the development of the welding process of G115 large-diameter pipes is of great significance to the manufacture of 630 ° C boilers. [0003] But at present, there is no relevant manufacturing experience of G115 materials at home and abroad. At the same time, G115 is a newly developed material. gropin...

Claims

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Application Information

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IPC IPC(8): B23K28/02B23K9/00B23K9/235
Inventor 危兆胜王萍刘海徐祥久李秋石刁旺战黄超赵卫君
Owner HARBIN BOILER
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