Please visit Boiler Tube Research (Super-Heater) Part 2 for previous explanation.

Observation of the micro-structure is required for viewing the phase change or is there a change of micro-structure that occur during pipeline use and also to prove that a broken pipe caused by erosion only. Samples taken from pipes that are experiencing thinning of the outer walls and the surface shape of a wave (Figure 2.7). Photos of specimens and the resulting micro-structure can be seen in Figure 2.8 up to 2.11.








The hardness test results on free damage area and the damaged area can be seen in Table 2.6.

From the results of analysis of micro-structure and test photos of hardness test in an area that experienced depletion can be concluded that:
1. Damage occurs not because of the influence of thermal deformation of plastic or, since there is no change in the micro-structure occurs significantly.
2. test results of violence in an area that is experiencing thinning a bit down.
3. macro photos Of looks that the thinning of the walls of tubes happens because the process of erosion.

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Previous explanation can be read on Boiler Tube Research (Super-Heater) Part 1.

Pipeline number 2 the condition can be seen in Figure 2.2. Visual inspection is performed to detect the location of damage to the pipe. The result can be seen in Figure 2.3 to 2.6.









From the visual inspection, conclusions may be drawn as follows:
1.Found the depletion of the outer wall pipe likely caused by erosion.
2.Found any moderately thick crust is strong enough and adhere to the outside of a pipe not subjected to erosion.
3.Did not find any excessive safety deposit on the inside of the pipe.
4.Not invent the ravages of corrosion, on the inside of pipes as, pitting corrosion, caustic corrosion or other kind of corrosion which seriously make damage .
5.Not found the depletion part of wall pipe in damage and no proof pipe beginning from the pipe

To test the truth of the conclusion on the results of the visual inspection, can be conducted a series of Metallurgy tests.


Chemical composition and Hardness test.
This test aims to prove that there is no mistake in choosing the material the pipe is used. Specification of the material used for secondary super-heater pipe classified as SA-213-T12. Results of testing the chemical composition and the violence will be compared with the standard ASTM A213.

Results of testing chemical composition and hardness test with the standard specifications can be seen in Tables 2.4 and 2.5.



Conclusion can be drawn from the testing material pipe is material a pipe used according to the specifications as specified.


Continue to Metal Micro-structure analysis and Hardness test on Boiler Tube Research Part 3 (Super-Heater).

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Pipe number #2 is a segment from the pipes in secondary super-heater area. Super-heater functional is increasing saturated steam temperature from a drum into more hot steam called steam super-heat by using hot gas from furnace combustion results. Super-heater divided into two, namely primary and secondary super-heater



Primary super-heater serves to raise a saturated steam temperature from a drum into steam super-heat by earn the hot gases from furnace combustion. Primary super-heater inlet temperature is 304C and outlet temperature is 414C.


Secondary super-heater is located at the crossing of very hot gas that is above the combustion chamber and the heat radiation is received directly from the combustion chamber. The steam temperature enter to secondary super-heater was 414 C and exit steam temperature was 541C, pressure 169 kg/cm2. Steam comes out of the secondary super-heater is then used to rotating the HP Turbine.

From information obtained that the pipeline has been operating for about 10 years, namely since 2004. The pipeline has not experienced to be replacement because it is designed to operate for approximately 30 years. This pipe number 2 materials (SSH Pipe) was originally stated to SA-213-T22, but on 2 May 2014 got confirmation that material actually is SA-213-T12. Specification in detail of the pipe and its operational conditions are described in Table 2.1 and Table 2.2.



Another information about operating condition, Inner pipe temperature 414C, Inner pressure 17 MPa and Flue Gas temperature 900C.

Visual Inspection of Super-heater tube can be read on Boiler Tube Research (Super-Heater) Part 2.

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