scholarly journals PENGARUH VARIASI HOLDING TIME TERHADAP KEMAMPUKERASAN BAJA MENGGUNAKAN ALAT UJI JOMINY

2018 ◽  
Vol 8 (2) ◽  
pp. 257
Author(s):  
Yusuf ◽  
Yudi Chandra
Keyword(s):  
Holding Time ◽  
Jominy Test

Kemampukerasan adalah kemampuan suatu material untuk dapat dikeraskan sampai kedalaman tertentu dengan cara perlakuan panas dengan properti mekanik, hingga terbentuk martensit pada proses pendinginan untuk mencapai kekerasan tertentu. Salah satu metode pengujian hardenability yaitu jominy test (Van Vlack, 1991). Uji jominy merupakan sebuah metode untuk mengetahui kemampuan pengerasan logam (baja). Pengujian jominy tes dilakukan berdasarkan standard ASTM A255. Pengujian dilakukan mengunakan baja ST 42 dengan panjang 100 mm dan diameter 25.4 mm dengan spesimen uji sebanyak 3 buah. Hasil pengujian spesimen 1 dengan holding time 30 menit menghasilkan nilai kemampukerasan 43,7 HRB, untuk spesimen 2 dengan Holding Time 60 menit menghasilkan nilai kemampukerasan 43,7 HRB, sedangkan pada spesimen 3 dengan holding Time 90 menit menghasilkan nilai kemampukerasan 47 HRB. Semakin lama dilakukan holding Time pada spesimen maka nilai kekerasan yang dihasilkan akan lebih tinggi.

scholarly journals Pengaruh jarak nozzle penyemprot terhadap kemampukerasan baja komersil dengan metode jominy test

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Yusuf Yusuf ◽  
Asep Ruchiyat ◽  
Muh Anhar
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
Test Method ◽  
Holding Time ◽  
Heat Treatment Process ◽  
Wear And Tear ◽  
Jominy Test ◽  
Specimen Number

Steel is the material most widely used in the industry. To avoid wear and tear on steel, it is necessary to do heat treatment to improve the mechanical properties of the steel according to its application in the field. The increase in hardenability in metals can be determined by doing a hardenability test, namely the Jominy test method. The Jominy test is a method to determine the hardness value of metal using ASTM standards. This research was conducted with varying the distance of the nozzle of the sprayer to the lower end of the specimen, namely 10 mm, 12.5 mm, and 14 mm with a long spraying time of 15 minutes. The heat treatment process at temperature of 780oC and 90 minutes holding time. The averagehardness value of specimen number one (10 mm spraying distance) is 45.43 kgf, specimen number two (12.5 mm spraying distance) is 45.68 kgf, and specimen number three (14 mm spraying distance) is 44.31 kgf. The highest hardness value was specimen number two, there was an increase of 1.87 kgf (4.02%), according to ASTM standards where the spraying distance was 12.5 mm.Keywords: Steel, spraying distance, Jominy test.

An Impact of Yogic Practices and Weight Training on Breath Holding Time of College Men Players

2012 ◽  
Vol 3 (1) ◽  
pp. 7-8
Author(s):  
Dr. A. S. NAGESWARAN Dr. A. S. NAGESWARAN ◽  
Keyword(s):  
Weight Training ◽  
College Men ◽  
Holding Time ◽  
Breath Holding

scholarly journals Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology

2021 ◽  
Vol 13 (12) ◽  
pp. 6739
Author(s):  
Darko Landek ◽  
Lidija Ćurković ◽  
Ivana Gabelica ◽  
Mihone Kerolli Mustafa ◽  
Irena Žmak
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Nonlinear Models ◽  
Slip Casting ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Aqueous Suspensions ◽  
Temperature Heating

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

scholarly journals A Response Surface Methodology (RSM) Approach for Optimizing the Attenuation of Human IgE-Reactivity to β-Lactoglobulin (β-Lg) by Hydrostatic High Pressure Processing

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1741
Author(s):  
Xin Sun ◽  
Jialing Vivien Chua ◽  
Quynh Anh Le ◽  
Francisco Trujillo ◽  
Mi-Hwa Oh ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Optimal Condition ◽  
Response Surface ◽  
High Pressure Processing ◽  
Molecular Structures ◽  
Holding Time ◽  
P Value ◽  
Molecular Change ◽  
Ige Reactivity ◽  
Β Lactoglobulin

The response surface methodology (RSM) and central composite design (CCD) technique were used to optimize the three key process parameters (i.e., pressure, temperature and holding time) of the high-hydrostatic-pressure (HHP) processing either standalone or combined with moderate thermal processing to modulate molecular structures of β-lactoglobulin (β-Lg) and α-lactalbumin (α-La) with reduced human IgE-reactivity. The RSM model derived for HHP-induced molecular changes of β-Lg determined immunochemically showed that temperature (temp), pressure (p2) and the interaction between temperature and time (t) had statistically significant effects (p < 0.05). The optimal condition defined as minimum (β-Lg specific) IgG-binding derived from the model was 505 MPa at 56 °C with a holding time of 102 min (R2 of 0.81 and p-value of 0.01). The validation carried at the optimal condition and its surrounding region showed that the model to be underestimating the β-Lg structure modification. The molecular change of β-Lg was directly correlated with HHP-induced dimerization in this study, which followed a quadratic equation. The β-Lg dimers also resulted in the undetectable human IgE-binding.

scholarly journals Effects of holding temperature and holding time on pore structures in porous aluminum fabricated by friction stir processing

2009 ◽  
Vol 59 (11) ◽  
pp. 642-646 ◽  
Author(s):  
Takao Utsunomiya ◽  
Yu-ichiro Ozeki ◽  
Yoshihiko Hangai
Keyword(s):  
Friction Stir Processing ◽  
Holding Time ◽  
Porous Aluminum ◽  
Friction Stir ◽  
Pore Structures ◽  
Holding Temperature

Influence of heating temperature and holding time on the formation sequence of iron aluminides at the interface of Fe/Al coatings

2021 ◽  
pp. 102516
Author(s):  
You Wang ◽  
Nan Deng ◽  
Zhangjian Zhou ◽  
Zhenfeng Tong
Keyword(s):  
Heating Temperature ◽  
Iron Aluminides ◽  
Holding Time
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