The Standardization of Durometers

1940 ◽  
Vol 13 (4) ◽  
pp. 969-978
Author(s):  
Lewis Larrick
Keyword(s):  
Standard Method ◽  
Hardness Test ◽  
Type A ◽  
Test Sample ◽  
Dead Load ◽  
Dead Weight ◽  
Pressure Gage ◽  
Hardness Tester ◽  
Vulcanized Rubber ◽  
Physical Tests

Abstract The hardness test is one of the most useful and convenient physical tests which can be made on vulcanized rubber. It is easily made because the equipment can be simple, compact and portable. It is particularly useful in that the test sample may be a production article which can be put into service, undamaged, after the test. Consequently the test appears in the industry in several modifications, and the tester in diverse styles. Several more or less readily portable hardness testers are available commercially. The Shore Instrument and Manufacturing Co. has its line of Durometers, types A, B, C, D, etc.; Schopper, through Testing Machines, Inc., has marketed a tester similar to the Shore type A; the U. S. Gauge Co. has an instrument of the same type using the case of their pressure gage; the Firestone Penetrometer is another well-known tester of the spring-load type, as is the Adams Densimeter. At the present time the Society's Committee D-11 on Rubber Products is studying four portable hardness testers which are based on the specifications of the Standard Method of Test for Hardness of Rubber (D314-39), three of these being spring-operated instruments, the fourth, a dead-load type. In addition to the testers mentioned above, there is the Pusey-Jones Plastometer, which is a dead-weight hardness tester rather than a plastometer.

Hardness Test and Error Analysis of N80 Oil Casing

2013 ◽  
Vol 779-780 ◽  
pp. 161-164
Author(s):  
Ding Feng ◽  
Zhi Min Li ◽  
Hong Zhang ◽  
Lei Shi ◽  
Wei Ma ◽  
...  
Keyword(s):  
Error Analysis ◽  
Hardness Test ◽  
Pressure Head ◽  
Test Sample ◽  
Rockwell Hardness ◽  
Load Pressure ◽  
Hardness Tester ◽  
Measurement Results ◽  
Causes Of Errors ◽  
Petroleum Drilling

N80 oil casing is important equipment in petroleum drilling, to analyze the mechanical features of the N80 casing; we used Rockwell apparatus to test the hardness of N80 casing. And we have analyzed and eliminated the errors which may affect the result of the hardness test to ensure the reliability. At the same time, it summed up the causes of errors and the methods to avoid and reduce the errors during the Rockwell hardness test, and analyzed the hardness tester load, pressure head, the structure as well as the test sample roughness, shape and other factors which influenced the measurement results. Keywords: n80 oil casing; hardness test; error analysis

Rationalization of the Hardness Testing of Rubber

1936 ◽  
Vol 9 (1) ◽  
pp. 83-94
Author(s):  
J. R. Scott
Keyword(s):  
Theoretical Basis ◽  
Practical Significance ◽  
Reverse Direction ◽  
Hardness Testing ◽  
Dead Weight ◽  
Rubber Industry ◽  
Hardness Tester ◽  
Vulcanized Rubber ◽  
Rubber Surface ◽  
Compression Characteristics

Abstract The object of this paper is to draw attention to the present unsatisfactory state of the hardness testing of vulcanized rubber and the need for standardization of this test, and also to present some results of an investigation into the theoretical basis of hardness testing and the practical significance of hardness measurements. In this paper the word “hardness” will be used in the sense generally accepted in the rubber industry, that is, to denote resistance to indentation. The most commonly used types of hardness tester measure hardness in terms of the depth of the indentation made by a rigid ball or blunt pin pressed into the rubber by either a dead weight or a spring. The reading given by such an instrument, usually termed the hardness number, must depend on several variable factors, namely (1) the dimensions of the ball or pin; (2) the weight used to press it into the rubber, or the compression characteristics of the spring in the case of spring-loaded instruments; (3) the direction of the scale of the instrument, i. e., whether the reading increases with the depth of indentation, as in the Pusey-Jones Plastometer, or in the reverse direction, as in the Durometer; (4) the units in which the indentation is measured, i. e., whether in 100ths of a millimeter, 1000ths of an inch, or arbitrary units. In addition to these factors relating to the instrument, the reading must also depend on the dimensions of the rubber test-piece, especially its thickness, the nature of the rubber surface, and the period for which the ball or plunger is pressed on to the rubber before the reading is taken.

scholarly journals PENINGKATAN SIFAT MEKANIS BESI COR KELABU MELALUI PROSES TEMPERING

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
A. Noor Setyo HD ◽  
Sri Widodo
Keyword(s):  
Cold Water ◽  
Hardness Test ◽  
Heating Time ◽  
Initial Energy ◽  
Test Results ◽  
Maximum Hardness ◽  
Quenching Temperature ◽  
Independent Variables ◽  
Hardness Tester ◽  
Water Media

This study aims to determine the Hardness and Toughness of cast iron after undergoing a Tempering process with independent variables heating time and dependent Hardness, microstructure and toughness Impack. Quenching was carried out at temperatures of 7750C, 8000C and 8250C in cold water media, while Tempering was carried out at temperatures of 2000C, 3000C and 4000C with a holding time of 15 minutes. Vickers Hardness test results using "Micro Hardness Tester" after Quenching have increased by an average of 95.6% at Quenching 7750C, 99.8% at Quenching 8000C and 107.1% at Quenching temperature 8250C from Hardness value of row material of 256.6 BHN or 260.8 VHN0,040. The maximum hardness value is obtained 531.4 BHN or 553.6 VHN 0,040 at Quenching temperature 8250C and the lowest Hardness of 501.8 BHN or 541,8 VHN0,040 at Quenching 7750C temperature, has Cementite phase as a matrix with little Martensite, is due to treatment The partial tempering of Martensite is replaced by the ferrite phase between Cementites. The results of the study concluded that at Tempering temperatures of 2000C, 3000C and 4000C, the toughness of FC 30 experienced an increase of 106.5%, 121.9% and 130.5% from the initial energy of 5.21 Joule / mm2, whereas violence decreased by 88, 6%, 80.8% and 40.4% of the original Hardness of 260.8 VHN 0,040

scholarly journals Thermoset Polymer Splicing Study Using a variation of welding

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Adi Prastyo Utomo ◽  
Prantasi Harmi Tjahjanti
Keyword(s):  
Hardness Test ◽  
Test Sample ◽  
Test Method ◽  
Polymer Materials ◽  
Hardness Testing ◽  
Hot Gas ◽  
Thermoset Polymer ◽  
Materials Used ◽  
Thickness Variations ◽  
Plastic Welding

There is not much plastic welding currently done and not much research has been done on plastic welding. The purpose of this study was to study the use of welding variations used to join the thermoset polymer material. The thermoset polymer materials used are acrylic, melamine and bakelit with the test sample measuring 80mm in length, 30mm in width and 3mm in thickness. Variations in welding are used using hot gas welding, electric soldering and gas torches. The test method is carried out after welding to determine the porosity of the weld using a penetrant liquid. Hardness testing was also carried out. The best welding results are shown on acrylic material using electric solder, showing that the amount of porosity is the least, and has the highest hardness test.

Hardness Testing of Vulcanized Rubber. II. Comparisons of Readings of Various Instruments

1944 ◽  
Vol 17 (1) ◽  
pp. 194-199
Author(s):  
H. A. Daynes ◽  
J. R. Scott
Keyword(s):  
The Other ◽  
Hardness Testing ◽  
Hardness Tester ◽  
Vulcanized Rubber

Abstract Tests have been made on numerous rubbers with the R.A.B.R.M. hardness gauge, the Strachan piezomicrometer, and the Pusey and Jones plastometer (using in each case ¼-in. and ⅛-in. diameter balls) and with the Shore durometer and Schopper hardness tester, to determine the relationships between the readings given by these instruments. The results are tabulated and represented graphically as correlation curves. A conversion chart is given by which the reading obtained with any one instrument or size of ball can readily be converted into the corresponding reading for any of the other instruments or sizes of ball.

The Hardness of Very Soft Rubbers

1956 ◽  
Vol 29 (3) ◽  
pp. 852-856
Author(s):  
R. F. Blackwell
Keyword(s):  
Calibration Curve ◽  
Laboratory Work ◽  
Dead Load ◽  
Scale Reading ◽  
British Standard ◽  
Hardness Tester ◽  
Alternative Method ◽  
The Dead ◽  
Dial Gauge

Abstract Hardness determinations are frequently required on very soft rubbers in the range of 5 to 30 (Shore). It is usual to make such measurements in the shop with a pocket-type tester; however this is not entirely satisfactory for laboratory work where a more precise reading is usually required, calling for a hardness tester of the dead-load type. Such a tester, moreover, is useful to keep a check on the accuracy of pocket testers. The British Standard dead-load hardness tester is not calibrated below 30° BS, but a method of extending the range downwards has been proposed, whereby the standard indentor of this tester is replaced by one of 0.25 inch diam.; unfortunately this method has the disadvantage of involving more than one revolution of the dial gauge needle, and a directly calibrated scale would be out of the question. There is, however, an alternative method in use at BRPRA, which gives hardness readings down to 4° in one revolution; and which replaces the standard added load of 535 grams by one of 70 grams. At present, a calibration curve is provided to convert from scale reading to hardness degrees, but it is intended to add a second scale in due course.

The Impact Resiliometer

1934 ◽  
Vol 7 (3) ◽  
pp. 591-598 ◽  
Author(s):  
Paul Lüpke
Keyword(s):  
Elastic Properties ◽  
Physical Science ◽  
Sustained Load ◽  
Plastic Properties ◽  
Dual Nature ◽  
Hardness Tester ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
The Impact ◽  
Average User

Abstract Original Purpose The writer's first conception of an instrument for quickly measuring the resilience of rubber samples arose in connection with the basic idea for and development of the present A.S.T.M. hardness tester, in an endeavor to provide a reproducible means of measuring and expressing those properties of rubber compounds superficially apparent to the average user. It seemed that if the resistance to pressure (indenting or flexing) and the pressure, or force, of recovery, of a sample were duplicated, the article produced would “feel” the same as the sample, and under normal conditions of use would act mechanically the same. Nature of Problem This problem of measurement, as is generally known, is complicated by the time-hysteresis characteristic of vulcanized rubber compounds, arising through a dual nature, and causing them to manifest both elastic and plastic properties. Any instrument which applies load momentarily measures the almost purely elastic properties, while one which applies a more or less sustained load measures elastic properties modified by the material's partially plastic nature. These ideas are expressed from commercial and industrial viewpoints without regard to their possible deviations from the strict definitions accepted in physical science.

scholarly journals Mechanical Properties of Anatomic Finishing Files: XP-Endo Finisher and XP-Clean

2018 ◽  
Vol 29 (2) ◽  
pp. 208-213 ◽  
Author(s):  
Eduarda Santiago Vaz-Garcia ◽  
Victor Talarico Leal Vieira ◽  
Natasha Pereira da Silva Ferreira Petitet ◽  
Edson Jorge Lima Moreira ◽  
Hélio Pereira Lopes ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Visual Inspection ◽  
Hardness Test ◽  
Cyclic Fatigue ◽  
Radius Of Curvature ◽  
Weibull Analysis ◽  
Micro Hardness ◽  
Significance Level ◽  
Hardness Tester ◽  
Improved Performance

Abstract The aim of the present study was to evaluate the cyclic fatigue of two anatomic finishing files: XP-Endo Finisher and XP-Clean. Roughness pattern and the micro-hardness of the files were also assessed. Instruments were subjected to cyclic fatigue resistance measuring the time to fracture in an artificial stainless-steel canal with a 60° angle and a 5-mm radius of curvature. The fracture surface of all fragments was examined with a scanning electron microscope. The roughness of the working parts was quantified by using a profilometer and the micro-hardness test was carried out using a Vickers hardness tester. Results were statistically analyzed using a student´s t-test at a significance level of P < 0.05. Weibull analysis was also performed. XP-Endo Finisher presented significantly longer cyclic fatigue life than XP-Clean instruments (P<0.05). XP-Endo Finisher was able to withstand 1000% more cycles to fracture when compared to XP-Clean instruments. SEM visual inspection of the fracture surfaces revealed fractographic characteristics of ductile fracture in all tested instruments; wide-ranging forms of dimples were identified and no plastic deformation in the helical shaft of the fractured instruments was observed. When mean life was compared XP-Endo Finisher lasted longer than XP-Clean with a probability of 99.9%. XP-Endo Finisher instruments also exhibited significantly lower roughness than XP-Clean instruments (P<0.05). No differences in the micro-hardness was observed between the files (P>0.05). It can be concluded that XP-Endo Finisher instruments showed improved performance when compared with XP-Clean instruments, demonstrating higher cyclic fatigue resistance and lower roughness.

The Effect of Annealing to the Hardness of Oxide Dispersion Strengthened (ODS) Fe-15Cr-0.3Y2O3 Alloy

2017 ◽  
Vol 888 ◽  
pp. 428-431
Author(s):  
Farha Mizana Shamsudin ◽  
Yusof Abdullah ◽  
Shahidan Radiman ◽  
Nasri A. Hamid
Keyword(s):  
Vickers Hardness ◽  
Spherical Shape ◽  
Hardness Test ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Alloy Matrix ◽  
Hardness Tester ◽  
Powder Particles ◽  
Average Size ◽  
Vickers Hardness Test

The objective of this study is to investigate the microstructure and effect of annealing to the hardness properties of oxide dispersion strengthened (ODS) Fe-15Cr-0.3Y2O3 alloy. This type of alloy was prepared by mechanical alloying (MA) method followed by compacting and sintering. The microstructure of milled Fe-15Cr-0.3Y2O3 alloy powders and pellet was examined by using field emission scanning electron microscope (FESEM). The milled alloy powders consist of nearly spherical shape of powder particles with average size of 10 µm. For the alloy pellet microstructure, the formations of Y2O3 nanoparticles with average size of 5 nm were observed indicating the dispersion and incorporation of this nano-scale dispersoids into the alloy matrix. Fe-15Cr-0.3Y2O3 alloy pellet was annealed at temperature of 600°C, 800°C and 1000°C, respectively for the Vickers hardness test. The Vickers hardness test was performed by using a micro-Vickers hardness tester with a load of 200 gf. The hardness value (HV) of this alloy pellet started to decrease at temperature of 600°C indicating the grain growth of this material at high temperature

scholarly journals Perbedaan Penggunaan Bahan Desensitizing dan Tanpa Desensitizing Pasca Bleaching Ekstra-Koronal terhadap Kekerasan Email

2012 ◽  
Vol 19 (2) ◽  
pp. 119
Author(s):  
Wignyo Hadriyanto
Keyword(s):  
Vickers Hardness ◽  
Artificial Saliva ◽  
Hardness Test ◽  
Acrylic Resin ◽  
Micro Hardness ◽  
Vickers Hardness Number ◽  
Hardness Tester ◽  
Group I ◽  
Significant Difference ◽  
The Subject

Latar Belakang. Pada bleaching ekstrakoronal diketahui terjadi proses demineralisasi sehingga terjadi hiersensitivitas dentin. UltraEZ salah satu bahan desensitizing yang dapat mengurangi hipersensitivitas akibat demineralisasi email pasca bleaching ekstrakoronal terkini. Tujuan penelitian ini bertujuan untuk mengetahui perbedaan kekerasan email pasca pemutihan gigi ekstra-koronal dengan aplikasi bahan desensitizing dan tanpa aplikasi bahan desensitizing. Metode penelitian ini menggunakan 20 gigi premolar permanen pasca pencabutanyang masih utuh dan direndam dalam saliva buatan, kemudian dilakukan pemolesan pada bagian bukal dengan menggunakan pasta profilaksis kemudian gigi dicuci dan dikeringkan. Bahan pemutih Opalescence Xtra Boost diaplikasikan pada semua permukaan bukal gigi premolar kemudian dibagi menjadi 2 kelompok yaitu kelompok I, II, masing-masing kelompok sebanyak 10 gigi. Kelompok I sebagai kelompok control setelah dilakukan pemutihan, tidak dilakukan aplikasi Ultra-EZ, dimasukkan dalam wadah botol dan direndam dalam saliva buatan kemudian disimpan dalam incubator. Mahkota dan akar gigi,kemudian ditanam dalam resin akrilik sesuai kelompok sebelumnya dengan permukaan bukal menghadap ke atas. Semua sampel diuji kekerasannya dengan uji kekerasan Vickers menggunakan beban 100 g selama 15 detik. Permukaan bukal menghadap ke atas, kemudian dijepit dengan alat penjepit pada meja alat Micro Vickers Hardness Tester. Sampel diatur sedemikian rupa sehingga akan terlihat gambar yang dapat diukur panjang diagonalnya langsung dengan micrometer yang ada pada lensa okuler. Nilai kekerasan email dalam Vickers hardness number (VHN) juga dapat diperoleh dari table setelah mengetahui rata-rata panjang diagonal, berat badan yang digunakan dan waktu yang digunakan untuk uji kekerasan. Pengujian ini dilakukan pada setiap kelompok. Selanjutnya diuji dengan uji-t. hasil penelitian menunjukkan ada perbedaan yang bermakna antara aplikasi ultraEZ lima menit dibandingkan tanpa aplikasi ultraEZ terhadap kekerasan email pada p>0,05. Background. One of the side effect of bleaching agent is a dentine hypersensitive and ultraEZ is an agent can diminish this process. The purpose of this study was to evaluate difference of enamel microhardness post external bleaching with or without ultra-eze application. Method. Twenty extracted permanent bicuspid used in this study were divided into two group, each group contains 10 bicupids. Group I was treated external bleaching without ultra-eze application and group II was treated external bleaching with application ultraEZ for five minutes. After that all of the subject were seaked the artificial saliva and kept in the incubator 24 hours. Teeth were embedded into acrylic resin with the buccal sirface facing up. Further all of the subject was evaluated by Vickers using 100 g load for 15 seconds. Teeth were stapled on the Micro Hardness Tester table diagonal of emage was measure using micrometer attach on ocular lesnse. Email hardness can be known after calculating, the everage diagonal length, the load used and the duration of hardness test. Further the data was analize using t-test. The result shows there is significant difference between bleaching with and without the application of ultra-eze.

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