For testing the truth of the allegations on the results of visual inspection, they conducted a series of tests to prove it.
Testing of chemical composition and hardness of Material Pipe 1.
Testing aims to prove that there is no mistake in choosing the material of the pipe that is used. Specification of the material used SA-210-C. Results of the chemical composition testing and the violence will be compared with the standard ASTM A201 that Standard Specification for Seamless Medium-Carbon Steel Boiler and Super-heater Tubes. Results of testing chemical composition and hardness test with the standard specifications can be seen in Tables 1.3 and 1.4.
Conclusion can be drawn from the pipe material test that the pipe material used according to the specifications as specified.
Metallographic and hardness analysis of Material Pipe 1.
Analysis of Metallographic and hardness to prove the occurrence of plastic deformation on defects that occur, then it needs micro structure observation that having defects (Figure 1.8) and free areas of defects. Then the hardness test also carry on to the area that got plastic deformation. The result of Micro-structure photographs can be seen in Figure 1.9 - 1.10.
Results of hardness test of pipe 1 are presented in Table 1.5 above.
From the results of microstructure photo test analysis and hardness test in the area around defects can be concluded that:
1. The defects occur due to plastic deformation caused by foreign bodies from outside the pipe. The collision occurs at temperatures below the re-crystallization temperature of metal (cold forming).
2. Hardness test results supported than, where the value of hardness in defect area are larger than in areas that are free of defects. The rise hardness value is evidence of plastic deformation in cold condition on defect area.
To be continue to XRD (X-Ray Diffraction) analysis on Boiler Tube (Bottom Slope) Research Part 4.
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