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High Electrical Potential Electrons - + X-ray Generator or Radioactive Source Creates Radiation Exposure Recording Device Radiation Penetrate the Sample.

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Presentasi berjudul: "High Electrical Potential Electrons - + X-ray Generator or Radioactive Source Creates Radiation Exposure Recording Device Radiation Penetrate the Sample."— Transcript presentasi:

1 High Electrical Potential Electrons - + X-ray Generator or Radioactive Source Creates Radiation Exposure Recording Device Radiation Penetrate the Sample

2 Definisi Non Destructive Test; NDT adalah pengujian material yang dilakukan tanpa harus merusak bagian konstruksi (produk, material) atau obyek yang diuji untuk mengetahui cacat baik cacat luar maupun cacat dalam.

3 Hasil pemeriksaan produk mengenai jenis cacat, bentuk, tempat yang diteliti, keadaan produk dan lain-lainnya harus dicatat secara tepat, dan langkah selanjutnya bagi produk yang lulus pemeriksaan, tingkat kualitasnya harus dicatat dan hasil pencatatan tersebut harus diberikan sebagai umpan balik pada bagian perencanaan teknik. Bagian perencanaan teknik mengadakan pengaturan kualitas menurut data tersebut dan dilaksanakan untuk pencegahan cacat- cacat. Untuk memelihara dan menyempurnakan data tersebut agar selalu dapat menyiapkan standar pemeriksaan yang lebih sempurna.

4 Tujuan dan Peranan Pengujian untuk menjamin mutu (kualitas) dan kepercayaan terhadap kontruksi (produk, material), yaitu dengan cara memisahkan produk yang gagal. penekanan biaya dengan mengetahui lebih dulu produk yang cacat, yaitu penerimaan bahan baku dan bahan yang diproses dari proses awal sampai akhir bahwa produk yang cacat diketahui seawal mungkin. penyempurnaan teknik, yaitu menyisihkan produk yang cacat dilakukan lebih awal dan langkah selanjutnya tingkat kualitas dapat dipelihara dengan memeriksa data secara kolektif, sehingga kualitas dan teknik pembuatan dapat disempurnakan.

5 Peranan pengujian atau pemeriksaan dapat dikelompokkan menjadi tiga kelas, yaitu pengujian untuk : Keperluan pembuat; untuk menunjang usaha- usaha perbaikan kepercayaan, kualitas produk (material), perbaikan teknik pembuatan, dan pengurangan biaya pembuatan. Keperluan pemakai; untuk kepastian kualitas saat pembelian, kepastian dan ketahanan kulaitas selama penggunaan, dan cara untuk memilih pembuat dan membandingkan hasil. Keperluan masyarakat; untuk penilaian terhadap kualitas produk (material), jaminan untuk keamanan masyarakat.

6 Untuk menjamin kualitas dan kepercayaan, pengujian atau pemeriksaan harus dilakukan secara terus menerus sejak dari tahap perencanaan sampai dengan tahap pemakaian. Tahap-tahap yang harus dilakukan antara lain: Pengujian atau pemeriksaan untuk penjajagan. Pengujian atau pemeriksaan untuk penelitian dan pengembangan. Disain meliputi: –pengujian atau pemeriksaan untuk pemilihan bahan –pengujian atau pemeriksaan untuk pembuat –pengujian atau pemeriksaan untuk penentuan persyaratan disain

7 Penggunaan meliputi : »pengujian atau pemeriksaan untuk penerimaan »pengujian atau pemeriksaan untuk perawatan Material : pengujian atau pemeriksaan penerimaan. Pembuatan meliputi : »pengujian atau pemeriksaan untuk cara pemrosesan »pengujian atau pemeriksaan untuk pemilihan kondisi proses »pengujian atau pemeriksaan untuk pengawasan kualitas »pengujian atau pemeriksaan untuk proses produksi

8 Persiapan Sebelum Pengujian Kepastian dari standar yang digunakan. Di dalam pengujian atau pemeriksaan terdapat bermacam- macam standar dengan spesifikasi yang berbeda-beda. Berhubung dengan hal tersebut, maka sebelum pengujian dilaksanakan harus ditentukan lebih dulu standar yang akan digunakan termasuk tahun penerbitannya. Kepastian tentang jadwal dan lingkungan pemeriksaan. Pengujian atau pemeriksaan produk menyesesuaikan jadwal proses produksi yang dibuat agar tidak menghambat seluruh pekerjaan dengan memperhitungkan kemungkinan adanya pekerjaan yang tidak memenuhi syarat yang akan memerlukan waktu tambahan untuk memperbaiki. Supaya tidak mengganggu pelaksanaan pemeriksaan, maka lingkungan pemeriksaan juga harus dipastikan lebih dahulu, agar pemeriksa dapat melakukan tugasnya dengan baik dan aman.

9 Pemilihan pemeriksa dan alat yang digunakan. Pemeriksaan sangat tergantung dari pemeriksa, metoda pemeriksaan, dan alat yang digunakan, oleh karena itu harus didasarkan pada spesifikasi dan standar yang ada. Persiapan benda uji. Sebelum melakukan pemeriksaan produk, harus ditentukan lebih dahulu cara-cara pengujian yang akan digunakan dengan memperhatikan perencanaan dan fungsi produk. Untuk penanganan produk hasil pemeriksaan, perlu dipelajari tentang cacat maupun letak cacat di dalam produk, dan dipersiapkan benda uji sesuai dengan persyaratan yang diperlukan, serta alat uji harus dikalibrasi terlebih dahulu sebelum digunakan. Persiapan Sebelum Pengujian (lanjutan)

10 NDT terhadap lasan, pada dasarnya memiliki 2 fungsi: Quality control, yang memonitor welder dan peralatan, kualitas, dan logam dasar yang dipergunakan. Diterima atau diafkir suatu hasil lasan yang disesuaikan dengan fungsinya. Tujuan utama Inspeksi las melalui NDT adalah keberadaan diskontinuitas. Sehingga diskontinuitas tersebut harus dideteksi, diidentifikasi, dicari lokasinya, ukurannya dan orientasinya.

11 Pertimbangan Pemilihan Metoda NDT pada Struktur Lasan: Karakteristik diskontinuitas Persyaratan mekanika perpatahan Ukuran komponen Kemampuan dibawanya peralatan Kendala-kendala lainnya: –Jalan masuk ke lokasi inspeksi –Geometri struktur (datar, lengkung, tebal, tipis, dll) –kondisi permukaan (halus, tidak beraturan, dll) –Mode inspeksi (preservice, in-service, kontinyu, periodik, sesaat) –Lingkungan (tidakj bersahabat, dibawah air, dll) –Waktu yang tersedia untuk inspeksi (cepat, intensif) –kehandalan –Aplikasi gabungan metoda pengujian –Harga

12 Metoda NDT: Visual Liquid Penetrant Magnetic Particle Eddy Current Ultrasonic Radiografi Microwave Acoustic Emission Thermography Laser Interferometry Replication Flux Leakage Acoustic Microscopy Magnetic Measurements Tap Testing

13 Five Most Common NDT Methods Visual Liquid Penetrant Magnetic Ultrasonic X-ray

14 Most basic and common inspection method. Tools include fiberscopes, borescopes, magnifying glasses and mirrors. Robotic crawlers permit observation in hazardous or tight areas, such as air ducts, reactors, pipelines. Portable video inspection unit with zoom allows inspection of large tanks and vessels, railroad tank cars, sewer lines. Visual Inspection

15 Visual inspection is useful for checking the following: Dimensional accuracy of weldments Conformity of welds to size and contour requirements Acceptability of weld appearance with regard to surface roughness, weld spatter, and cleanness Presence of surface flaws such as unfilled craters, pockmarks, undercuts, overlaps, and cracks. Visual inspection is useful for checking the following: Dimensional accuracy of weldments Conformity of welds to size and contour requirements Acceptability of weld appearance with regard to surface roughness, weld spatter, and cleanness Presence of surface flaws such as unfilled craters, pockmarks, undercuts, overlaps, and cracks. (a) Mirror on stem: may be flat for normal view or concave for limited magnification. (b) Hand magnifying glass (magnification usually 2–3´). (c) Illuminated magnifier; field of view more restricted than D (magnification 5–10´). (d) Inspection glass, usually fitted with a scale for measurement; the front surface is placed in contact with the work (magnification 5–10´). (e) Borescope or intrascope with built-in illumination (magnification 2–3´). (a) Mirror on stem: may be flat for normal view or concave for limited magnification. (b) Hand magnifying glass (magnification usually 2–3´). (c) Illuminated magnifier; field of view more restricted than D (magnification 5–10´). (d) Inspection glass, usually fitted with a scale for measurement; the front surface is placed in contact with the work (magnification 5–10´). (e) Borescope or intrascope with built-in illumination (magnification 2–3´).

16 Gage for visual inspection of a fillet weld at a 90° intersection. Similar gages can be made for other angles. Dimension given in inches Gage for visual inspection of a fillet weld at a 90° intersection. Similar gages can be made for other angles. Dimension given in inches

17 Appearance Standards. Workmanship standard for visual comparison during inspection of single-V-groove welds and fillet welds. Dimensions given in inches

18 A liquid with high surface wetting characteristics is applied to the surface of the part and allowed time to seep into surface breaking defects. The excess liquid is removed from the surface of the part. A developer (powder) is applied to pull the trapped penetrant out the defect and spread it on the surface where it can be seen. Visual inspection is the final step in the process. The penetrant used is often loaded with a fluorescent dye and the inspection is done under UV light to increase test sensitivity. Liquid Penetrant Inspection

19 Magnetic Particle Inspection The part is magnetized. Finely milled iron particles coated with a dye pigment are then applied to the specimen. These particles are attracted to magnetic flux leakage fields and will cluster to form an indication directly over the discontinuity. This indication can be visually detected under proper lighting conditions.

20 Radiography The radiation used in radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see as visible light. The radiation can come from an X-ray generator or a radioactive source. High Electrical Potential Electrons - + X-ray Generator or Radioactive Source Creates Radiation Exposure Recording Device Radiation Penetrate the Sample

21 Film Radiography Top view of developed film X-ray film The part is placed between the radiation source and a piece of film. The part will stop some of the radiation. Thicker and more dense area will stop more of the radiation. = more exposure = less exposure The film darkness (density) will vary with the amount of radiation reaching the film through the test object.

22 Radiographic Images

23 High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws. Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features that reflect sound. f plate crack initial pulse crack echo back surface echo Oscilloscope, or flaw detector screen Ultrasonic Inspection (Pulse-Echo)

24 Three positions of the contact type of transducer along the zigzag scanning path used during ultrasonic inspection of welded joints. The movement of the sound beam path across the weld is shown on a section taken along the centerline of the transducer as it is moved from the far left position in the scanning path (a), through an intermediate position (b), to the far right position (c). Sound beam path in a flat testpiece being ultrasonically inspected with a shear wave from an angle-beam transducer, showing the skip distance between the nodes where the beam reflects from the surfaces

25 Ultrasonic scanning procedures to detect longitudinal and transverse discontinuities in welds that (a) are not ground flush and (b) are ground flush

26 Ultrasonic scanning procedure for full- penetration groove weld (a) and double-fillet welds (b) in corner joints

27 Discontinuity Signals Transducer scanning positions for distinguishing between weld metal flaws that are (a) vertically oriented and (b) in an inclined position

28 Common Application of NDT Inspection of Raw Products Inspection Following Secondary Processing In-Services Damage Inspection

29 Inspection of Raw Products Forgings, Castings, Extrusions, etc.

30 Machining Welding Grinding Heat treating Plating etc. Inspection Following Secondary Processing

31 Cracking Corrosion Erosion/Wear Heat Damage etc. Inspection For In-Service Damage

32 Power Plant Inspection Probe Signals produced by various amounts of corrosion thinning. Periodically, power plants are shutdown for inspection. Inspectors feed eddy current probes into heat exchanger tubes to check for corrosion damage. Pipe with damage

33 Wire Rope Inspection Electromagnetic devices and visual inspections are used to find broken wires and other damage to the wire rope that is used in chairlifts, cranes and other lifting devices.

34 Storage Tank Inspection Robotic crawlers use ultrasound to inspect the walls of large above ground tanks for signs of thinning due to corrosion. Cameras on long articulating arms are used to inspect underground storage tanks for damage.

35 Aircraft Inspection Nondestructive testing is used extensively during the manufacturing of aircraft. NDT is also used to find cracks and corrosion damage during operation of the aircraft. A fatigue crack that started at the site of a lightning strike is shown below.

36 Jet Engine Inspection Aircraft engines are overhauled after being in service for a period of time. They are completely disassembled, cleaned, inspected and then reassembled. Fluorescent penetrant inspection is used to check many of the parts for cracking.

37 Pressure Vessel Inspection The failure of a pressure vessel can result in the rapid release of a large amount of energy. To protect against this dangerous event, the tanks are inspected using radiography and ultrasonic testing.

38 Rail Inspection Special cars are used to inspect thousands of miles of rail to find cracks that could lead to a derailment.

39 NDT is used to inspect pipelines to prevent leaks that could damage the environment. Visual inspection, radiography and electromagnetic testing are some of the NDT methods used. Remote visual inspection using a robotic crawler. Radiography of weld joints. Magnetic flux leakage inspection. This device, known as a pig, is placed in the pipeline and collects data on the condition of the pipe as it is pushed along by whatever is being transported. Pipeline Inspection

40 Macam-macam Jenis Cacat

41 Macam-macam Jenis Cacat (lanjutan)

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