Metallographic corrosive liquid for bimetal composite pipe with transition layer and etching method of metallographic corrosive liquid

A technology of bimetal composite pipe and corrosive liquid, which is applied in the preparation of test samples, etc., can solve the problems of wide transition layer, cracks, pores, etc., and achieve the effect of reliable operation

Active Publication Date: 2013-05-01
DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For stainless steel and low-alloy steel composite pipes, due to the different materials of the inner and outer layers, the two metals are combined together, and problems such as delamination, impurities, cracks, and pores are prone to occur at the joint surface.
Especially for the bimetal composite pipe prepared by centrifugal casting process, unlike other mechanical composite processes, the base material and cladding material can be inspected separately before combining to determine whether they meet the standard requirements, which can only be detected on the composite pipe body The properties of the substrate or cladding, and there is a wide transition layer at the junction of the two metals

Method used

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  • Metallographic corrosive liquid for bimetal composite pipe with transition layer and etching method of metallographic corrosive liquid
  • Metallographic corrosive liquid for bimetal composite pipe with transition layer and etching method of metallographic corrosive liquid
  • Metallographic corrosive liquid for bimetal composite pipe with transition layer and etching method of metallographic corrosive liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Corrosion solution composition: 0.02-0.03g / ml ferric chloride; 50% concentrated hydrochloric acid (analytical pure) ethanol (analytical pure) solution (volume ratio of concentrated hydrochloric acid to ethanol).

[0037] The ground and polished SA-213 TP310HCbN and SA-213 T11 (the said TP310HCbN and T11 are seamless austenitic and ferritic alloy steel pipes for boilers, superheaters and heat exchangers, ASME SA-213 / The listed steel number in SA-213M, ASME Ⅱ-A-2010 SA-213 / SA-213M P315~326 pages) The composite pipe sample is immersed in the prepared corrosive solution, the polished surface of the sample is facing upward, completely Immerse in the liquid, during this period, you can dip the absorbent cotton ball into the corrosion solution to slightly wipe the polished surface, keep it for 1.5Min, take out the sample after the specified time, rinse it in still water and dry it with hot air for microscopic observation . Microscopic results such as Figures 1 to 6 shown,...

Embodiment 2

[0039] Corrosion solution composition: 0.01-0.02g / ml ferric chloride; 55% concentrated hydrochloric acid (analytical pure) ethanol (analytical pure) solution (volume ratio of concentrated hydrochloric acid to ethanol).

[0040]Immerse the ground and polished SA-213 TP310HCbN and SA-213 T11 composite pipe sample in the prepared corrosive solution, with the polished side of the sample facing up, and completely immerse in the liquid. During this period, you can use absorbent cotton balls to immerse in the corrosive solution Slightly wipe the polished surface and keep it for 1Min. After the specified time, take out the sample, rinse it in still water and dry it with hot air for microscopic observation. Microscopic results such as Figure 7-12 shown. in Figure 7 It is the microscopic appearance map of the overall composite tube observed under the microscope at 50 magnifications (the position of the observation point at 200 magnifications is marked in the figure, where d represen...

Embodiment 3

[0042] Corrosion solution composition: 0.03g / ml ferric chloride; 40-45% concentrated hydrochloric acid (analytical pure) ethanol (analytical pure) solution (volume ratio of concentrated hydrochloric acid to ethanol).

[0043] Immerse the ground and polished SA-213 TP310HCbN and SA-213 T11 composite pipe sample in the prepared corrosive solution, with the polished side of the sample facing up, and completely immerse in the liquid. During this period, you can use absorbent cotton balls to immerse in the corrosive solution Slightly wipe the polished surface and keep it for 1Min. After the specified time, take out the sample, rinse it in still water and dry it with hot air for microscopic observation. Microscopic results such as Figure 13-18 shown. in Figure 13 It is the microscopic appearance map of the overall composite tube observed under the microscope at 50 magnifications (the position of the observation point at 200 magnifications is marked in the figure, where d represe...

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Abstract

The invention discloses metallographic corrosive liquid for a bimetal composite pipe with a transition layer, belonging to the technical field of detection of bimetal composite pipes. The corrosive liquid is prepared by adding ferric trichloride to a concentrated hydrochloric acid ethanol solution with the volume ratio of 35-60 percent, wherein the ferric trichloride addition amount is 0.01-0.04g/ml. The corroding method comprises the following steps of: completely immersing a polished sample to the corrosive liquid, and maintaining for 0.3-2Min. The invention provides the corrosive liquid which is suitable for daily metallographic inspection, low in cost and free of pollution and a corroding method of the corrosive liquid aiming at a metallic stainless steel and low alloy steel composite pipe which is produced by adopting a metallurgical bonding process and is provided with a wide transition layer at a bonding surface between stainless steel and low alloy steel. The corrosive liquid and the corroding method disclosed by the invention can be used for simultaneously corroding metallic tissues from the stainless steel, the low alloy steel and the wide transition layer for the purpose of detection.

Description

technical field [0001] The invention belongs to the detection field of bimetallic composite pipes, in particular to the metallographic detection of bimetallic composite pipes with a transition layer. Background technique [0002] The bimetallic composite pipe has the excellent properties of the two component metals. After the proper combination of the two component metals, it can obtain high strength, corrosion resistance, electrical conductivity, thermal conductivity and other comprehensive properties, so that the bimetal can be used in some special environments. It can play a role that is difficult for a single metal. At present, stainless steel and low-alloy steel bimetal composite pipes are being more and more widely used in petroleum, chemical, electric power, energy and other industries. [0003] At present, the domestic and foreign academic and industrial circles have been committed to the development of bimetallic composite pipes. Japan has successfully developed a ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F1/28G01N1/32
Inventor 张学星毛世勇代黎李健
Owner DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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