1. Ringkasan
1.1 This test method includes methods for evaluating the tensile properties of vulcanized thermosetting rubber and thermoplastic elastomers. This test method can not be used to test hard glue and materials with high hardness and low elongation. Cara pengujiannya adalah sebagai berikut:

Metode A — Straight bar and dumbbell samples

Metode B — Spesimen berbentuk lingkaran

Komentar 1 -the results of the two tests are incomparable.

1.2 Satuan berdasarkan SI atau non-SI dianggap sebagai satuan standar standar ini. Since the results of using different unit systems may be different, unit yang berbeda harus digunakan secara terpisah dan tidak dicampur.

Keamanan

2 Referensi
D 1349 Spesifikasi karet — Standard test temperature

D 1566 Rubber related terminology

D 3182 Spesifikasi karet — Bahan, equipment and procedures for making standard compounds and standard vulcanization test pieces

D 3183 Spesifikasi karet — Preparation of test pieces from finished products

D 4483 Standard test methods for rubber and carbon black industrial species – Specification for measurement accuracy

2.2 ASTM Annex

Persiapan spesimen berbentuk cincin, Metode B

Standar ISO

ISO 37 – Methods for determination of tensile stress-strain properties of vulcanized or thermoplastic rubber

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

3 Terminologi
3.1 Definisi

3.1.1 Deformasi tarik jangka panjang — The residual deformation of the sample after elongation under a certain action, when the applied force is relieved, dinyatakan sebagai persentase dari panjang aslinya.

3.1.2 Long stretching deformation — The long stretching deformation of the pulled dumbbell sample is closely pressed to the cross section.

3.1.3 Kekuatan tarik — The maximum force generated in the process of breaking the sample.

3.1.4 Daya tarik — the stress used when drawing the sample

3.1.5 Stres ekstensi yang konstan — the stress generated when a sample of regular section is stretched to a specific length.

3.1.6 Thermoplastic elasters — a material similar to rubber, namun berbeda dengan karet vulkanisir biasa, dapat diproses dan didaur ulang seperti plastik.

3.1.7 Perpanjangan saat putus — the elongation of the specimen when it breaks during continuous stretching.

3.1.8 Titik hasil — The point on the stress-strain curve where the velocity of the stress change with respect to strain becomes 0 and opposite before the final failure of the specimen.

3.1.9 Ketegangan hasil — Tingkat regangan pada titik luluh

3.1.10 Hasil stres — Tingkat stres pada titik luluh

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

Method Description
4.1 For the test of tensile properties, samples are first cut from the sample material, including two parts: sample preparation and test. The shape of the specimen can be dumbbell, ring atau batang lurus, dan bentuk bagiannya teratur.

4.2 Penentuan kekuatan tarik, stres fiksasi, titik leleh dan perpanjangan putus tanpa perpanjangan awal sampel. Penentuan kekuatan tarik, stres fiksasi, yield point and elongation at break for the specimen with normal section is based on the original cross-sectional area of the specimen.

4.3 Long-term deformation by stretching and long-term deformation by tearing, measure the deformation of the sample after stretching and shrinking according to the prescribed method.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

Key Points and Applications
5.1 Bahan atau produk yang terlibat dalam pengujian ini harus mengalami gaya tarik dalam proses penerapan sebenarnya. This test is to determine such tensile properties. Namun, the tensile properties do not directly represent the whole situation of the final use of the product, because the product needs to cover a wide range of potential use conditions in actual use.

5.2 Tensile properties are dependent on materials and test conditions (kecepatan tarik, uji suhu dan kelembaban, geometri sampel, penyesuaian pra-tes, dll.). Karena itu, hasil pengujian bahan pada kondisi yang sama sebanding.

5.3 Test temperature and tensile speed have significant effects on tensile properties, yang harus dikontrol secara ketat. And the effect varies with different materials.

5.4 Deformasi tarik jangka panjang mewakili deformasi sisa sampel. Ini mewakili deformasi jangka panjang dan pemulihan sebagian sampel setelah peregangan dan retraksi. Karena itu, proses peregangan dan retraksi (dan kondisi pengujian lainnya) need to be tightly controlled to ensure comparable results.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

6 Peralatan
6.1 Mesin tarik — The tensile testing machine shall have an electric drive mechanism to ensure that the separation speed of the sample chuck is constant 500±50mm/min, and the minimum stroke is 750mm(Lihat Catatan 1). The testing machine should have a suitable dynamometer and reading recording system to ensure that the measured force deviation is within ±2%. Jika jangkauan mesin penguji tidak dapat diubah (Misalnya, dinamometer pendulum), then the deviation of the measured force when the sample is broken is ±2% of the full range of the dynamometer, and the accuracy of the measured minimum force is 10%. If the dynamometer has an automatic compensation function in the direct measurement of tensile stress, then the compensation function for the cross-sectional area of the specimen should be turned off during the measurement. The recording device should be fast enough to measure the force and ensure the required accuracy during the whole process of specimen failure. If the testing machine does not have a recording device, there should be an indicator to indicate the maximum force value during stretching. Perpanjangan harus diukur dalam sistem pengujian dengan kenaikan minimum 10%.

Catatan 1 — Jika kecepatan tarik yang digunakan adalah 1000±100mm/menit, itu harus ditunjukkan dalam laporan pengujian. In case of doubt, the test should be repeated at a speed of 500mm/min.

6.2 High and low temperature test box — the test box should meet the following requirements:

6.2.1 Di ruang ujian, there should be a heat flow around the position of the chuck and the shaft, kecepatan sekelilingnya adalah 1 menjadi 2m/s, and the temperature is kept within the range of 2 ° C of the required temperature deviation.

6.2.2 Use the calibrated temperature measuring device to measure the actual temperature near the chuck and shaft.

6.2.3 The test chamber shall have an exhaust ventilation device to discharge the gas released in high temperature (Sampel) into the atmosphere.

6.2.4 Sebelum ujian, sampel harus ditempatkan secara vertikal di dekat chuck dan poros untuk penyesuaian. Specimens should not be in contact with each other or with the walls of the test chamber except for transient contact caused by agitation of the surrounding air.

6.2.5 Place the chuck appropriately to facilitate operation in high and low temperature environments. Lewat sini, the dumbbell or straight strip specimens are placed into the chuck for as short a time as possible to reduce the temperature change of the test chamber.

6.2.6 The dynamometer should be suitable for working at the test temperature, or have good insulation with the test chamber.

6.2.7 Elongation measuring device shall be provided in the test chamber. If a ruler is used to measure the elongation of the specimen scale, the ruler should be placed parallel to the scale close to the path of the chuck movement and can be controlled from outside the test chamber.

6.3 Thickness gauges — Thickness gauges shall meet the requirements of Specification D 3767(Metode A). Untuk spesimen berbentuk cincin, lihat Artikel 14.10 dari metode pengujian ini.

6.4 Pengukuran deformasi tarik jangka panjang — Use test equipment as described in 6.1 atau seperti yang ditunjukkan pada Gambar 1. The stopwatch or other timing device should have a range greater than 30min, and the measuring accuracy of the ruler or other measuring device for elongation should be within 1%.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

7 Pemilihan sampel
7.1 The following points should be considered when selecting samples

7.1.1 The anisotropy and orientation of the material caused by the flow during preparation and treatment can affect the tensile properties. Karena itu, in the preparation of dumbbell or straight bar specimens, under the premise of knowing the calendering direction, arah pemotongan sampel harus sejajar dengan arah penanggalan. Untuk spesimen berbentuk cincin, the orientation characteristics are usually averaged to a certain extent.

7.1.2 Kecuali ditentukan, for thermoplastic rubbers or elasteers, specimens shall be cut from injection molded specimens with a thickness of 3.0±0.3mm, and the test results obtained from specimens of other thicknesses shall be comparable. The samples should be two sets of perpendicular and parallel forming flow directions. The size of the test piece or test plate should be able to meet the test requirements.

7.1.3 The elongation of the annular specimen can be measured by the separation of the collet, but the elongation distribution on the radius width of the specimen is inconsistent. Untuk mengurangi efek ini, the sample width should be smaller than the diameter of the annular sample.

7.1.4 When the sample is used for ordinary tensile test, the failure of the sample generally occurs in the chuck. Karena itu, the straight bar specimen is used only when the sample cannot be made of other shapes. For non-destructive stress-strain or material modulus experiments, straight strip specimens should be used.

7.1.4 Ukuran sampel tergantung pada kebutuhan material, alat uji dan sampel yang digunakan untuk pengujian. Untuk bahan dengan perpanjangan putus yang rendah, longer specimens can be used to improve the accuracy of elongation measurement.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

Kalibrasi alat uji
8.1 Calibrate the test machine according to Procedure A of Specification E 4 for dynamometers of measuring precision type, and calibrate one or more force points according to the 7 Dan 18 test of specification E 4. For pendulum dynamometers, ikuti langkah-langkah berikut untuk mengkalibrasi:

8.1.1 Masukkan salah satu ujung sampel halter ke dalam chuck mesin uji.

8.1.2 Lepaskan chuck bawah dari mesin penguji, artinya, the clamping mechanism of the sample is on the upper chuck of the testing machine.

8.1.3 Pasang pengait pada chuck bawah untuk menahan ujung bawah sampel

8.1.4 Hang a weight with a known weight on the hook, so that a certain mass can be temporarily applied to the lower fixture of the sample (Lihat Catatan 2).

8.1.5 Turn on the fixture movement monitoring device and keep it running until the weight is free to hang on the sample in the ordinary test.

8.1.6 If a disc or ruler (or equivalent tester for stress compensation) does not indicate force values within the specified accuracy, the equipment should be effectively checked for faults (misalnya. friction on shafts or other moving parts). Perlu ditentukan bahwa massa chuck dan hook bawah juga diperhitungkan.

8.1.7 Setelah gesekan dan kesalahan lain dari mesin uji dihilangkan, the testing machine is calibrated to know that the weight is measured at three points at about 10, 20 Dan 50% dari skala penuh mesin pengujian. If ratchets and spines are used in normal testing, they should also be used in calibration. Friction is checked by mounting a ratchet.

Catatan 3 — There should be a device to prevent weights from falling from the test machine.

8.2 Pegas dapat digunakan untuk perkiraan kalibrasi cepat.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

9 Suhu uji
9.1 Kecuali ditentukan, suhu pengujian standar adalah 23±2℃. Sampel harus disesuaikan pada 23 ° C setidaknya 3 jam. Jika bahan dipengaruhi oleh kelembapan, spesimen harus dikondisikan pada 50±5%R.H. untuk lebih dari 24 jam sebelum ujian. Jika diuji pada suhu lain, suhu yang tercantum dalam Spesifikasi D 1349 akan digunakan.

9.2 If the test is carried out at A temperature higher than 23℃, sampel metode A harus dipanaskan terlebih dahulu selama 10±2 menit; Method B should be preheated for 6±2min. Sebelum setiap interval pengujian, the specimens are placed in the test chamber separately, so that all specimens are continuously subjected to the same warm-up time. Preheating tests at high temperatures should be strictly limited to prevent persulphation and thermal aging.

Catatan 3 — Peringatan: Di antara peringatan lainnya, use insulated, cold gloves to protect hands from high and low temperatures. Masker harus digunakan selama percobaan suhu tinggi untuk mencegah terhirupnya gas beracun ketika pintu kotak percobaan dibuka.

9.3 Untuk uji suhu rendah, sampel harus didinginkan terlebih dahulu setidaknya selama 10 menit.

Metode pengujianA — Straight bar and dumbbell specimens

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

10 Peralatan
10.1 Cutting Knife — The shape and dimensions of the cutting knife shall be as shown in Figure 2. The inside of the narrow part of the cutter shall be perpendicular to the cutter end face and at least 5mm from the cutter end face shall be polished. The shape of the cutter should remain unchanged without defects. (Lihat Catatan 4)

Catatan 4 — Kondisi alat pemotong dapat diketahui dengan mengamati titik patah sampel. The fractured sample was removed from the chuck and spliced along the fracture surface to observe whether the sample failure occurred at the same location. Jika kegagalan terjadi di lokasi yang sama, it means that the cutter may become blunt, cacat, atau bengkok di lokasi ini.

10.2 Marking lines — Two marking lines drawn on the sample to measure elongation and strain are called marking lines (Lihat Catatan 5). The marker shall include a flat plate with two bumps parallel to each other. Permukaan yang terangkat (sejajar dengan permukaan pelat) harus memiliki bidang yang panjang dan sempit, dan kedua sisinya harus ditempatkan pada bidang yang sama. Pesawat yang ditinggikan adalah 0.05 lebar hingga 0,08 mm dan panjang minimal 15 mm. The Angle between the plate and the bulge was at least 75º. Jarak antara pusat kedua bidang yang ditinggikan harus dijaga tetap dalam jarak 1% of the required or target distance deviation. A handle shall be included on the back or top of the marker.

Catatan 4 — No marking is required if contact extensionometers are used.

10.3 Ink Marks — Gunakan flat, permukaan keras (kayu keras, logam, atau plastik) to make ink or toner marks. The ink or toner should be firmly bonded to the sample, not corroding the sample, and contrast with the color of the sample.

10.4 Chuck — Meteran uji memiliki dua collet, salah satunya dihubungkan dengan dinamometer.

10.4.1 The chuck of the test dumbbell sample should have a self-tightening device to generate constant pressure on the surface of the chuck, and the clamping force should increase with the increase of elongation to prevent sliding and make the failure occur in the narrow part of the sample. A constant pneumatic chuck is also applicable. There is a special part in the broken part of the fixture so that the sample can be inserted into the fixture with the same length and the stress distribution is uniform.

10.4.2 The fixture used for testing straight strip samples shall have pneumatic fixture, mulut penjepit atau gesper baut, so that the clamping force of the fixture can be applied evenly to the entire width of the sample.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

11 Sampel
11.1 Spesimen halter — Kapanpun memungkinkan, specimens should be injection molded or cut from specimens 1.3 tebalnya hingga 3,3 mm. The thickness and size of the specimen can be cut by one test method (see Specification D 3182). Benda uji dapat dibuat langsung atau dipotong dan dipoles dari produk jadi. If the test piece is prepared directly from the finished product, permukaannya tidak boleh dari kulit atau kain yang keras. According to the requirements of specification D 3183. All specimens shall be cut parallel to the length of the specimen, kecuali ditentukan. Jika spesimen disiapkan sesuai spesifikasi D 3182, ketebalannya harus 2,0±0,2 mm dan dipotong sepanjang orientasi material. Use C type cutter (ARA. 2), use a simple stamping device, and ensure the smoothness of the cut surface. .

11.1.1 Memberi Label pada Spesimen Dumbbell — Dumbbell specimens shall be marked as described in 10.2, and the specimens shall not be subjected to tension when marked. The marking line should be drawn on the narrow part, at the same distance from the center of the sample and perpendicular to the vertical axis. The distance between the two marks is 25.00±0.25mm for type C and type D samples. The other is 50.00±0.5mm

11.1.2 dumbbell sample thickness measurement — The thickness of the sample should be measured at three points, one at the center and two at the ends of the narrow part. The median of the three values is used to calculate the cross-sectional area. Jika kisaran ketebalan sampel lebih besar dari 0.08, the sample is rejected. Lebar sampel dapat dihitung sesuai dengan lebar bagian kerja pemotong.

11.2 Spesimen strip lurus — If dumbbells or annular specimens cannot be cut from the sample, spesimen strip lurus (misalnya, narrow strips, tabung kecil, or fine electrical insulation) can be cut. Spesimen harus cukup panjang untuk dimasukkan ke dalam perlengkapan. The marking is made as 11.1.1. Untuk menghitung luas penampang uji dari tabung, massa, panjang dan kepadatan tabung harus digunakan. Luas penampang dihitung sebagai berikut:

A=M/DL(1)(1)

Di mana:

A= luas penampang,cm2

M= massa,G

D = kepadatan,gram/cm3

L = panjang,cm

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

12 Langkah
12.1 Penentuan tegangan tarik, kekuatan tarik dan titik luluh — Masukkan sampel halter ke dalam perlengkapan mesin penguji, pay attention to adjust the gripping symmetry of the sample, agar gaya tarik merata pada bagian sampel. Hal ini akan menghindari perkiraan gaya tarik spesimen yang berlebihan. The test speed is 500±50mm/min(Lihat Catatan 7) unless special requirements are required. Start the testing machine and pay attention to the marking to prevent the influence of parallax. The force values at special elongation and at fracture of the sample were recorded. Elongation can be measured using extensionmeters, automated plotting, or optical tracking systems. Keakuratan pengukuran perpanjangan pada patahan berada dalam batasnya 10%. The calculation is given in 13.

Catatan 8 — Jika titik leleh sampel di bawah 20% perpanjangan saat kecepatan pengujian 500±50mm/menit, kecepatan pengujian dapat dikurangi menjadi 50±5mm/menit. Jika titik leleh sampel masih dibawah 20% pemanjangan, kecepatan pengujian dapat dikurangi menjadi 5±0,5 mm/menit. Sample speed should be recorded.

12.2 Penentuan deformasi tarik jangka panjang — The sample is loaded into the testing machine or device described in 6.1 seperti yang ditunjukkan pada Gambar 1. Care should be taken to adjust the gripping symmetry of the sample so that the tensile force is evenly distributed on the sample cross section. The speed of the chuck separation should be as constant as possible, so that the time to reach the prescribed elongation is 15s, and this elongation is maintained for 10min. Setelah 10 menit, the load was released immediately and allowed to return freely for 10min. Setelah itu, the residual deformation within the standard distance was measured, and the measurement accuracy was 1% dari jarak aslinya. Use a stopwatch to track the time. Melihat 13 untuk perhitungan.

12.3 Measurement of long-term fracture deformation — Setelah sampel dipecah selama 10 menit, the sample should be carefully spliced together to measure the residual deformation within the standard distance, and the calculation is shown in 13

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

13 Perhitungan
13.1 Perhitungan kekuatan pada setiap perpanjangan:

where

T(XXX)= kekuatan pada perpanjangan (XXX)%,MPa

F(XXX)= tegangan pada perpanjangan tertentu,M N

A= cross-sectional area of the sample,m2

13.2 Perhitungan kekuatan luluh

where

Y(menekankan)= kekuatan luluh,MPa

F(kamu)= kekuatan luluh,M N

A= cross-sectional area of the sample,m2

13.3 The yield point is evaluated as the point on the stress-strain curve where the velocity of the stress change with respect to strain becomes zero and opposite before the final failure of the specimen.

13.4 Perhitungan kekuatan tarik

where

TS = kekuatan tarik,MPa

F(MENJADI)= maximum force at fracture,M N

A= cross-sectional area of the sample,m2

13.5 Compute the elongation at any elongation;

where

E = persentase perpanjangan (jarak dalam skala),%

L = jarak pengamatan dalam jarak standar sampel,mm

L(0)= length of the sample’s original marking distance,mm

13.6 Elongation at break is calculated by substituting L at the time of sample fracture into Equation 5.

13.7 Rumus 5 can also be used to calculate long-term deformation, as long as L in the formula is substituted by the residual deformation after 10 menit.

13.8 Test Results — Hasil tes dinyatakan sebagai median dari hasil tiga sampel independen yang berurutan. Dalam dua kasus khusus, lima sampel diuji dan nilai median dari lima sampel dilaporkan.

13.8.1.Kasus spesial 1 — When the results of one or two samples in the test do not meet the specified measurement.

13.8.2 Kasus spesial 2 — For arbitral tests.

Metode B — Spesimen berbentuk lingkaran

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

14 Peralatan
14.1 Pemotong — A circular cutter is shown in Figure 3. Use a cutting knife to cut the annular sample from the flat test piece, and install a part of the upper shaft of the cutting knife into the rotary compression device, under which the test piece can be fixed in the rubber fixing device.

14.1.1 Penahan kedalaman bilah — The cylindrical disk in the retainer shall be at least 0.5mm thicker than the thickness of the rubber sheet to be cut. Its diameter should be smaller than the inner diameter of the sample, sehingga tonjolan mata pisau dapat diatur dari alat pemotong. Lihat Gambar 3

14.2 Pelat pemasangan karet — A device for holding rubber in place during cutting, the upper and lower surfaces parallel to each other, and made of hard polymeric materials (lem keras, poliuretan dan polimetil metakrilat). Holes of about 1.5mm in diameter are distributed at intervals of 6 to 7mm through the center of the plate. All these holes shall communicate with the mold cavity inside to reduce the air pressure used to hold the test piece. Angka 4 is used to hold the standard test piece (sekitar 150×150×2mm) selama pemotongan.

14.3 Sumber tekanan udara — A vacuum pump can be used to maintain a suction force of 10kPa on the specimen at the center of the gripper mold cavity.

14.4 Soapy water — Use neutral soapy water to lubricate the knife.

14.5 Pemotongan putar — Use a precision rotary machine or other equipment that can provide a speed of at least 30rad/s to cut the test piece. The cutter rotating device shall be mounted on a horizontal plane with a vertical positioner to support the rotating connecting rod and the shaft used for the cutter. Eksentrisitas poros yang berputar harus kurang dari 0,01 mm.

14.6 Built-in table — There shall be a table or other device that can be moved along the x-y axis respectively to hold and position the test piece so that the test piece corresponds to the axis of rotation of the rotary cutter.

14.7 Mesin uji tarik — shall comply with the requirements described in 6.1.

14.8 Perlengkapan Tes — The fixture of the annular sample is shown in Figure 5. Mesin pengujian harus dikalibrasi sesuai dengan 8 artikel.

14.9 Test chambers — High and low temperature test chambers shall meet the requirements in 6.2.

14.9.1 Perlengkapan tersebut tidak hanya cocok untuk pengujian pada suhu kamar. Namun, di bawah suhu khusus, pelumasan yang tepat harus digunakan untuk memastikan pelumasan poros yang berputar.

14.9.2 Dinamometer harus sesuai untuk digunakan pada suhu operasi atau diisolasi dengan baik dari ruang uji.

14.10 Pengukur Ketebalan — Thickness gauges shall meet the requirements of Specification D 3767(Metode A).

14.10.1 The main components of the thickness gauge, permukaan pengukuran atas berbentuk silinder (longitudinal axis along the vertical direction) setidaknya tinggi 12mm dan diameter 15,5±0,5mm. In order to fit the small annular sample, the measuring head with diameter of 15.5mm is used to measure, dan pengukurannya tidak akan menyebabkan pemanjangan sampel. The bottom of the cylindrical surface can be cut off half along the center so that there is no interference when measuring small samples. Ujung pengukur yang melengkung juga dapat digunakan.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

15. Spesimen berbentuk lingkaran

15.1 Spesimen Annular ASTM — Ada dua jenis, generally 1-shaped specimens are used

15.1.1 Ukuran sampel

Jenis 1

The inner perimeter is 50.0±0.01mm

Diameter bagian dalam adalah 15,92±0,003mm

The radial width is 1.0±0.01mm

The thickness is 1.0~3.3mm

Jenis 2

The inner perimeter is 100.0±0.2mm

Diameter bagian dalam adalah 29,8±0,06mm

The radial width is 2.0±0.02mm

The thickness is 1.0~3.3mm

15.2 Spesimen ISO Annular — Specimens are classified as normal and small according to ISO 37, yang menentukan prosedur pengujian khusus mereka.

biasa

The inner diameter is 44.6±0.2mm

The outer diameter is 52.6±0.2mm

The thickness is 4.0±0.2mm

Ukuran kecil

Diameter dalam 8,0±0,1mm

Diameter luar 10,0±0,1mm

The thickness is 1.0±0.1mm

15.3 Potong sampel berbentuk lingkaran dari pipa — the diameter of the annular sample should be determined by the wall thickness of the pipe and should meet the requirements of the product.

15.4 Persiapan sampel pemotongan — Place the blade in the holder of the cutter and adjust the depth of the blade. Tempatkan pemotong pada mesin press putar dan sesuaikan poros atau meja sehingga bagian bawah dudukan pisau berada 13 mm di atas pelat penahan sampel.. Shrink the stopper with the rotating shaft moving vertically. This allows the end of the blade retainer to penetrate the surface of the plate. The sample was placed into the gripper and the cavity pressure was reduced to 10kPa. Basahi permukaan benda uji dengan air sabun netral. The cutter should be stopped after reducing the cutter at a constant speed, and the cutter gripper should not touch the test piece at this time. Adjust blade depth if necessary. Reset the shaft before the next cutting.

15.5 Preparation of a sample cut from a tube — A shaft is inserted into the tube, the diameter of which is slightly larger than the diameter of the tube. Place the shaft and tube together on the machine tool. The specimen of the required axial thickness is cut from the sample with the blade or cutter on the machine tool. For thin-walled tubes, when laid flat, a cutter with two parallel blades can be used to cut.

15.6 Annular sample:

15.6.1 Perimeter — The inner perimeter can be measured with a cone or gauge. Tidak ada tegangan yang dapat digunakan untuk mengubah eliptisitas spesimen annular selama pengukuran. Keliling median dapat didasarkan pada keliling bagian dalam, meridional width, and π(3.14).

15.6.2 Lebar radial — Distribute three measuring points equally on the circumference of the specimen as per the thickness gauge in 14.10.

15.6.3 Ketebalan — The thickness of the disk from the inner circle to the outer circle can be measured by a thickness meter according to specification D 3767 when cutting annular specimens.

15.6.4 Luas penampang — Cross-sectional area was calculated as the median of three measurements: radial width and thickness. Untuk sampel dinding pipa tipis, the cross-sectional area was calculated using the axial length of the cutter and the wall thickness.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

16 Proses
16.1 Penentuan tegangan tarik, daya tarik, perpanjangan titik putus dan titik leleh benda uji berbentuk cincin – dengan pelumasan poros yang sesuai dengan perlengkapan pelumas, seperti minyak mineral atau minyak silikon. Should choose to use the prescribed and have no impact on the material. Perhitungan dan penyetelan posisi awal pusat poros kedua perlengkapan tersebut adalah sebagai berikut:

Di mana:

IS= initial distance from the center of the jig axis,mm

C(TS)= perimeter of the sample, untuk tipe 1 sampel adalah diameter dalam, untuk tipe 2 sampel adalah diameternya,mm

C(SP)= circumference of the jig shaft,mm

The test speed was 500±50 mamms (lihat Catatan 7 Dan 8), unless otherwise required. Start the test machine and record the force and the relative displacement of the two jig axes. Elongation and stress were recorded at fracture. The calculations are given in Section 17,

Catatan 8 — The test speed was 100±10mm/min using small ring type samples of ISO.

16.2 Eksperimen pada suhu non-standar — Gunakan ruang uji seperti yang dijelaskan dalam 6.2 and read the warning in Note 2. For tests higher than 23 °C, sampel dipanaskan terlebih dahulu pada suhu ini selama 6±2 menit. Untuk pengujian di bawah suhu kamar, sampel harus diatur pada suhu tersebut setidaknya selama 10 menit. Suhu pengujian di D 1349 seharusnya digunakan. Test pieces shall be placed in test chambers separately to meet requirement 9.2.

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

17 Perhitungan
17.1 Kecuali satu poin penting, the stress-strain properties of the ring specimen are calculated as those of the dumbbell or straight strip specimen. Ketika spesimen annular diregangkan, the stress distribution of each edge of the annular specimen is not uniform in width (dari kiri ke kanan). The initial inner diameter of the sample is smaller than the initial outer diameter. Karena itu, the stress in the inner test is greater than that in the outer test in the sample stretching, caused by the different initial size.

17.2 The following options are available for calculating tensile and breaking strengths.

17.2.1 Fixed elongation stress — The median perimeter of the annular specimen was used to calculate the elongation. The reason for using the median perimeter is that it corresponds to the average over the edges of the annular specimen.

17.2.2 Perpanjangan saat putus — Keliling bagian dalam benda uji annular digunakan sebagai dasar perhitungan, as it corresponds to the maximum stress on each edge of the specimen. This position is also the starting position of the sample failure.

17.3 Tegangan ekstensi konstan dihitung berdasarkan Persamaan 2 di dalam 13.1

17.3.1 Perpanjangan yang digunakan untuk menentukan gaya dalam Persamaan 2 (13.1) dihitung sebagai berikut

Di mana:

E = perpanjangan,%

L= increase in the distance between fixtures,mm

MC(TS)= keliling median sampel,mm

17.3.2 In Equation 7, the distance between fixtures at fixed extension is calculated using the following equation:

17.4 Titik luluh dihitung berdasarkan Persamaan 3 di dalam 13.2

17.5 Menggunakan 13.3 to determine the yield stress. Karena tegangan luluh digunakan untuk mengevaluasi sifat material secara keseluruhan, keliling median digunakan untuk menghitung.

17.6 Calculate tensile strength according to Formula 4 di dalam 13.4.

17.7 Elongation at break is calculated according to the following formula (lihat Catatan 9 Dan 10)

Di mana:

E = perpanjangan putus,%

L= the increased distance of the fixture at break,mm

IC(TS)= keliling dalam awal pola,mm

17.8 The inner perimeter can be used for both types of specimens (melihat 15.1.1 ukuran). Tipe keliling bagian dalam 2 spesimen annular dihitung menggunakan diameter dalam.

Catatan 9 — Persamaan 7 Dan 8 can only be used if the initial spacing of the fixture is adjusted according to Equation 7.

Catatan 10 — Caution should be taken when using this method because stresses at elongations slightly below the elongation at break (4 ke 5%) may not be calculated when different sizes are used to calculate 1) fixed elongation stress (kurang dari tegangan putus) Dan 2) perpanjangan saat putus (melihat 20.1 Dan 20.2).

ASTM D412-0 “Metode Uji Tarik Karet Vulkanisir dan Elastomer Termoplastik”

18 Report
18.1 The report should include the following:

18.1.1 Based on the results of Section 13 atau 17

18.1.2 Jenis sampel dan deskripsi, sesuai dengan tipe pemotong 13 bagian, di Amerika, unit buatan sendiri atau metrik

18.1.3 Date of experiment

18.1.4 Uji kecepatan

18.1.5 Suhu dan kelembaban laboratorium

18.1.6 Suhu uji (jika tidak 23±2℃)

18.1.7 Date of vulcanization or (Dan) rubber preparation, if possible

19 Akurasi dalam penyimpangan (dihilangkan)

20 Kata Kunci (dihilangkan)