MONITORING PROSES CREEP SECARA TAK RUSAK DENGAN METODE ULTRASONIK

ABSTRAK

MONITORING PROSES CREEP SECARA TAK RUSAK DENGAN METODE ULTRASONIK. Banyak komponen PLTN yang mengalami degradasi material diakibatkan oleh fenomena creep karena beroperasi pada lingkungan temperatur dan tegangan tinggi. Untuk mencegah terjadinya kegagalan selama PLTN beroperasi, dilakukan penelitian monitoring proses creep secara tak merusak dengan metode ultrasonik. Pengujian ultrasonik dilakukan terhadap material yang telah mengalami uji creep dengan berbagai variasi waktu pengujian. Hasil pengujian menunjukkan bahwa semakin lama pengujian creep berlangsung, cepat rambat gelombang ultrasonik mengalami penurunan, sedangkan atenuasi mengalami kenaikan, yang disebabkan cacat di dalam spesimen yang berupa void yang berkembang menjadi retak mikro dan retak makro. Keberadaan cacat ini akan mengganggu perambatan gelombang sehingga yang mengakibatkan penurunan cepat rambat. Selain itu, cacat di dalam spesimen akan menghamburkan gelombang ultrasonik sehingga memperbesar atenuasi.

KATA KUNCI: Degradasi material, Monitoring tak rusak, Metode ultrasonik

ABSTRACT

NON-DESTRUCTIVE MONITORING OF CREEP PROCESS USING ULTRASONIC METHOD. Material degradation due to creep phenomenon often occurs in many NPP’s components in high temperature and stress environment. To prevent failures during NPP operation, study of non-destructive monitoring of creep process using ultrasonic method was conducted. Ultrasonic tests were performed on material following creep test under various elapsed time. Testing results show that the propagation velocity of ultrasonic wave decreased and attenuation increased with increasing time of creep test, which were caused by defects that occurred in the specimen in the form of voids which turned into microcracks and macrocracks. The presence of these defects disturbed wave propagation, thus resulting in the decrease of propagation velocity. In addition, defects in the specimen also would scatter the ultrasonic wave which resulted in the increase of attenuation.

FREE TERMS: Material degradation, Non-destructive monitoring, Ultrasonic method