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A method for simultaneous hot bending of boiler tubes and cladding of outer surface corrosion-resistant layers

A technology for boiler tubes and corrosion-resistant layers, applied in coatings, fusion spraying, metal material coating processes, etc., can solve problems such as large differences in thermal expansion coefficients, poor bonding of coatings and elbows, etc., to achieve tightness Combining and avoiding the effect of large difference in thermal expansion coefficient

Active Publication Date: 2022-06-28
XIAN THERMAL POWER RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the shortcomings of spray coating on the bent pipe after the bending is completed, the combination effect of the coating and the bent pipe is not good, and the thermal expansion coefficient is relatively different, and to provide a method for synchronously performing hot bending of boiler tubes and external The method of surface corrosion resistant layer cladding

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A method for simultaneously performing hot bending of boiler tubes and cladding of an outer surface corrosion-resistant layer, comprising the following steps:

[0027] Step 1. Use a supersonic plasma spray gun to pre-spray the corrosion-resistant self-fluxing alloy powder on the straight boiler tube; the wall thickness of the straight boiler tube is 5mm, the outer diameter is 45mm, the length is 300mm, and the density of the corrosion-resistant alloy is 8.0g / cm 3 . After calculation, the total amount of corrosion-resistant self-fluxing alloy powder corresponding to 1 / 5 thickness of the sprayed layer is 346g;

[0028] Among them, the components of the corrosion-resistant self-fluxing alloy powder are, in parts by weight, 6 parts of Ni, 2 parts of Co, 1 part of Al, 0.5 parts of Si, 0.5 parts of B and inevitable impurities, and the corrosion-resistant self-fluxing alloy powder particles Degree is 250 ~ 300 mesh;

[0029] The rate of pre-spraying was 5g / s and the time was...

Embodiment 2

[0036] A method for simultaneously performing hot bending of boiler tubes and cladding of an outer surface corrosion-resistant layer, comprising the following steps:

[0037] Step 1. Use a supersonic plasma spray gun to pre-spray the corrosion-resistant self-fluxing alloy powder on the straight boiler tube; the wall thickness of the straight boiler tube is 8mm, the outer diameter is 60mm, the length is 400mm, and the density of the corrosion-resistant alloy is 8.0g / cm 3 . After calculation, the total amount of corrosion-resistant self-fluxing alloy powder corresponding to 1 / 5 of the thickness of the sprayed layer is 990g;

[0038] Among them, the components of the corrosion-resistant self-fluxing alloy powder are, in parts by weight, 6 parts of Ni, 2 parts of Co, 1 part of Al, 0.5 parts of Si, 0.5 parts of B and inevitable impurities, and the corrosion-resistant self-fluxing alloy powder particles Degree of 200 ~ 300 mesh;

[0039] The rate of pre-spraying was 8 g / s and th...

Embodiment 3

[0045] A method for simultaneously performing hot bending of boiler tubes and cladding of an outer surface corrosion-resistant layer, comprising the following steps:

[0046] Step 1. Use a supersonic plasma spray gun to pre-spray the corrosion-resistant self-fluxing alloy powder on the straight boiler tube; the wall thickness of the straight boiler tube is 7mm, the outer diameter is 50mm, the length is 200mm, and the density of the corrosion-resistant alloy is 8.0g / cm 3 . After calculation, the total amount of corrosion-resistant self-fluxing alloy powder corresponding to 1 / 5 of the thickness of the sprayed layer is 361g;

[0047] Among them, the components of the corrosion-resistant self-fluxing alloy powder are, in parts by weight, 6 parts of Ni, 2 parts of Co, 1 part of Al, 0.5 parts of Si, 0.5 parts of B and inevitable impurities, and the corrosion-resistant self-fluxing alloy powder particles Degree is 250 ~ 300 mesh;

[0048] The rate of pre-spraying was 10 g / s and t...

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Abstract

The invention discloses a method for synchronously performing hot bending of boiler tubes and cladding of an outer surface corrosion-resistant layer, belonging to the field of material modification. The invention comprises: step 1, pre-spraying the straight boiler tube with corrosion-resistant self-fluxing alloy powder; step 2, placing the pre-sprayed straight boiler tube in a heating furnace with a protective atmosphere, and clamping the straight boiler tube Put it into the hot bending fixture and heat it; Step 3. After heating for 30 minutes, bend the straight boiler tube, and use the spray gun in the furnace to spray the corrosion-resistant self-fluxing alloy powder for the second time; wherein, the powder for the second spraying The mass ratio of the amount of powder to the amount of pre-sprayed powder is 2:1; step 4, after the boiler tube bending and secondary spraying are completed, keep warm for 30 minutes, take it out and cool it in the air, and obtain a boiler tube hot bend with a corrosion-resistant layer. The invention effectively enhances the bonding strength between the coating and the metal substrate of the boiler tube, greatly delays the cracking time of the coating, and improves the service life of the coating.

Description

technical field [0001] The invention belongs to the field of material modification, in particular to a method for simultaneously performing hot bending of boiler tubes and cladding of an outer surface corrosion-resistant layer. Background technique [0002] Boiler tube elbows of thermal power units have been subjected to the action of fly ash and corrosive flue gas for a long time, which is prone to wear and corrosion and thinning, resulting in a decrease in pressure bearing capacity and even tube bursting, which affects the safe operation of the unit. The traditional method of thermal spraying of corrosion-resistant coating is to spray on the bent pipe after bending. The combination effect of the coating and the bent pipe is not good, and the thermal expansion coefficient is quite different. It is very easy to crack the coating during operation. , affect the corrosion resistance effect, and even lead to cracking of boiler tubes. SUMMARY OF THE INVENTION [0003] The purp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21C37/28C22C19/03C23C4/06C23C4/134
CPCB21C37/28C23C4/06C23C4/134C22C19/03
Inventor 崔雄华杨哲一
Owner XIAN THERMAL POWER RES INST CO LTD