Vikings Earlander Ragnar Lodbrok

In the saga-Nordic and Germanic saga that tells the story of Viking exploration, described in enough detail how the death of their king namely Ragnar Lodbrok. AELLE king of the kingdom of Northumbria who beat Ragnar Lodbrok by putting it in the well contains a full vipers.

Ragnar Lodbrok helpless and arguably his death is the leading cause loosening of the spirit of the Vikings in exploring and colonizing other nations in Europe. Besides wave of Christianization of Western Europe to North Europe increasingly massive at the time.

Even so, the Vikings with king Ragnar Lodbrok very famous it remains a phenomenon at once serious and real threat to other nations in Europe at the time. His name is remembered, the Nordic (Northern Europe) to this day still has a passion to "roam" in the world.

Then? How the story in fiction television series Viking? Will the story Ragnar Lodbrok and this Vikings will be the same as that written in the sagas that already exist? This is certainly worth listening to, so far in the fourth season and episode ten, Ragnar Lodbrok and children were still very strong and unbeaten by King AELLE of Northumbria though. Find the answer at the end of January 2017 after the release of television series.

:)

Wear Rate of Metals (AISI 630)

Present work aimed at investigating the wear resistance of AISI 630 (UNS S17400) or 17-4 PH stainless steel hardened by precipitation hardening or aging at various hardness levels.

The PHs steels are an interesting family of steels for applying in highly stressed parts for its corrosion resistance and relative high hardness, attaining up to 49 HRC by low-temperature aging heat treatment, low distortion and excellent weldability.

The wear tests by sliding and/or abrasion were performed in a pin-on-disc tribometer whose pins had three different hardness levels (43, 37 and 33 HRC) obtained by varying the precipitation hardening treatment. The counterface discs were machined from the same steel composition and aged to the hardness of 43 HRC.

The steels wear resistances were evaluated, using sliding velocity of 0.6 m/s, normal load of 30 N, total sliding distance of 2400 m and controlled room temperature and humidity of 27 °C and 60%, respectively.

From the analysis of plotted graphs of cumulative lost volume versus sliding distance, it was observed the different wear rates as function of the heat treatment and hardness. Due to the pins different hardness, the wear resistance varied substantially.

The wear mechanisms were also investigated through scanning electron microscopy observations of the worn surfaces of the pins. It can be asserted that the decrease in the pin hardness yields to lower pin wear resistance.

The disc wear was more severe as the difference in hardness between pin and disc increased. It was presented a list of mean wear resistance, establishing the best heat treatment that minimize the wear in this material for sliding wear applications.

For the investigated range of heat treatment and hardness, the 17-4 PH steel pins with hardness of 43 HRC showed the best wear resistance of 1941 and the pin with 33 HRC the worst wear resistance of 1581.
Keywords

    Wear testWear resistancePH stainless steelHeat treatment

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    Corresponding author. Tel.: +55 47 4009 7958; fax: +55 47 4009 7940.

AISI 52100 Specification

ASTM A295 is specification which covers 52100 high carbon bearing quality steel to be used in the manufacture of anti-friction bearings. And 52100 bearing steel is the most common steel grade in ASTM A295 standard for high-carbon anti-friction bearing steel.

What is 52100 bearing steel?

AISI/ASTM 52100 bearing steel is a high carbon, chromium containing low alloy steel that is through hardening and noted in particular for use as bearings.astm aisi 52100 bearing steel

52100 bearing steel is one kind of special steel with features of high wear resistance and rolling fatigue strength. High-carbon chromium bearing steel, engineering steel and some types of stainless steel and heat resistant steel are used as materials of bearings and for other purposes.

Advantages of Chrome Bearing Steel 52100:

    Superior hardness, 60-67 on Rockwell hardness scale (Rc) at room temperature
    High carbon chrome alloy steel
    Operates continually at temperatures up to 120°C
    Used to produce precision ball bearings and roller bearings
    Cost-effective
    Long working life

1. Supply Range of ASTM 52100 Bearing Steel

AISI 52100 Steel Round Bar: diameter 8mm – 800mm
52100 Steel Plate: thickness 2mm –300mm x width 200mm – 800mm
Other sizes of 52100 steel as per customer’s requirements
Process: Cold drawn, hot rolled, forged etc.
Surface Finish: black, rough machined, turned, polished or as per given requirements.

2. Relevant Steel Specification of ASTM 52100 Bearing Steel
Country USA German Japan British
Standard ASTM A295 DIN 17230 JIS G4805 BS 970
Grades 52100 100Cr6/1.3505 SUJ2 535A99/EN31

3. Chemical Composition of 52100 Bearing Steel and Equivalents
Standard Grade C Mn P S Si Ni Cr Cu Mo
ASTM A295 52100 0.93-1.05 0.25-0.45 0.025 0.015 0.15-0.35 0.25 1.35-1.60 0.30 0.10
DIN 17230 100Cr6/1.3505 0.90-1.05 0.25-0.45 0.030 0.025 0.15-0.35 0.30 1.35-1.65 0.30 –
JIS G4805 SUJ2 0.95-1.10 0.50 0.025 0.025 0.15-0.35 – 1.30-1.60 – –
BS 970 535A99/EN31 0.95-1.10 0.40-0.70 – – 0.10-0.35 – 1.20-1.60 – –

4. Mechanical Properties of ASTM A295 52100 Bearing Steel
Properties Metric Imperial
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Hardness, Brinell – –
Hardness, Knoop (converted from Rockwell C hardness) 875 875
Hardness, Rockwell C (quenched in oil from 150°C tempered) 62 62
Hardness, Rockwell C (quenched in water from 150°C tempered) 64 64
Hardness, Rockwell C (quenched in oil) 64 64
Hardness, Rockwell C (quenched in water) 66 66
Hardness, Vickers (converted from Rockwell C hardness) 848 848
Machinability (spheroidized annealed and cold drawn. Based on 100 machinability for AISI 1212 steel) 40 40

    52100 Steel Physical Properties

Properties Metric Imperial
Density 7.81 g/cm3 0.282 lb/in³
Melting point 1424°C 2595°F

    52100 Alloy Steel Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@ 23-280°C/73.4- 36°F, annealed) 11.9 µm/m°C 6.61 µin/in°F
Thermal conductivity (typical steel) 46.6 W/mK 323 BTU in/hr.ft².°F

5. Forging of A295 52100 Bearing Steel

AISI 52100 alloy steel is forged at 927 to 1205°C, and should not be forged below 925ºC. A post-forge equalization treatment is recommended at 745ºC for 4-6 hours followed by air cooling for SAE/AISI 52100 steel.

6. Heat Treatment for ASTM 52100 Bearing Steel

ASTM/AISI 52100 alloy bearing steel is heated at 816°C followed by quenching in oil. Before performing this process, it is subjected to normalizing heat treatment at 872°C followed by slowly cooling in order to reduce the machining stress.

Hot Working

AISI 52100 bearing steels alloy can be hot worked at 205 to 538°C.

Cold Working

AISI 52100 bearing steel can be cold worked using conventional techniques in the annealed or normalized conditions.

Annealing

For spheroidize anneale, the following isothermal anneal is recommended:

    1500ºF (815ºC) for 3 hours
    1350ºF (735ºC) for 4 hours
    1250ºF (675ºC) for 3 hours
    Slow cool to 1000ºF (540ºC) then air cool.

Quenching

AISI 52100 alloy bearing steel could be hardened by quenching in water from 801-829 degree or quench in oil from 816-842 degree.

Tempering

Temper to desired hardness as indicated by tempering curves after water or oil quench.

7. Applications of 52100 Bearing Steel

Alloy steel 52100 grade bearing steel is mainly used for the manufacture of aircraft bearings and other highly stressed parts. This steel grade 52100 steel is preferably vacuum arc re-melted to give optimum performance.

Typical applications: Bearing Manufacture, CV joints, ball screws, gauges, knife etc.

Otai Steel is one of reliable and serious special steel supplier of 52100 bearing steel materials. We stock and export such bearing steels worldwide. In the end of each month, we may have some 52100 bearing steel materials for sale or in discount. You are free to request a 52100 bearing steel price anytime.

Es Buah Pembawa Rejeki

Aslinya Malang, Jawa Timur, nama panggilannya Cak gondrong. Berawal dari gerobak kecil jualan es buah di depan pabrik YKK, kini ia sudah memiliki sedikitnya lima buah rombong besar di sekitar Cibitung. Satu di pinggir Kalimalang depan YKK, dua di gang monyet dan maspion, dan dua lagi di jarakosta.

Banyak cerita pahit darinya sebelum ia meraih pencapaian seperti sekarang ini. Ya, omset kelima rombong es buahnya dalam sehari bisa mencapai 4-6 juta. Belum termasuk pisang cokelat yang ia jajakan juga berbarengan di lapaknya. Saat bulan puasa justru menggila, omset dari semua gerobak-gerobak es buahnya tersebut pernah mencapai 10 juta per hari.

Semua itu tentu tidak asal cling bimsalabim abrakadabra seperti orang main sulapan. Ia, Cak Gondrong memiliki sederet kisah pilu yang tidak semua bisa saya tuangkan dalam secuil kisah ini. Dari pertama ia jualan dengan rombong kecil dan diusir satpam, hingga proses belajarnya ke tukang buah di pasar induk Cibitung, untuk belajar menentukan buah yg berkualitas sehingga saat dijadikan es buah rasanya tentu benar-benar segar.

Jarih payahnya selama tidak kurang dari 10 tahun sekarang dapat ia dan keluarganya rasakan. Di kampung halamannya di Malang sana ia sudah mampu berinvestasi sebidang tanah, yang rencananya di masa tua nanti ingin ia jadikan sebuah ruko kecil untuk menikmati sisa hidup. Adapun di sini semua orang di komplek perumahannya memanggilnya pak bos, meski ia lebih suka memperkenalkan dirinya sebagai cak gondrong.

Kuncinya hanya satu dan sederhana, yaitu ulet. Meski itu sangat sukar untuk dituangkan dalam proses menuju sukses tersebut. Yang pasti menurut Cak Gondrong, tak ada yg mustahil jika kita mau berusaha tak kenal putus asa (tahan banting) dan tentu tak lupa dilanjut berdoa kepada Tuhan YME. Semoga kisah ini menginspirasi kita semua, dan yang tinggal di sekitar Bekasi Kabupaten boleh kiranya mampir di lapaknya. 

***Kisah ini hasil perjumpaanku dengan bos es buah, Cak Gondrong di lapaknya kemarin sore saat mampir icip-icip es buah dan piscoknya.***

Manfaat Donor Darah Bagi Kesehatan Pendonor

Donor darah merupakan salah satu kegiatan sosial yang bertujuan untuk membantu antar sesama manusia yang sedang membutuhkan transfusi darah. Namun, bila ditelisik dari segi kesehatan ternyata mendonorkan darah tidak hanya bermanfaat bagi mereka yang membutuhkanya. Tapi, kita sebagai pendonor, turut mendapatkan manfaat besar bagi kesehatan diri sendiri ketika rutin mendonorkan darah.

Berikut 8 manfaat donor darah bagi kesehatan apabila rutin mendonorkan darahnya ke Palang Merah Indonesia (PMI), seperti dikutip dari Boldsky.com :

1. Mengurangi penyakit jantung

Salah satu manfaat kesehatan dari mendonorkan darah secara teratur adalah membuat jantung Anda senantiasa sehat. Dengan melakukan donor darah, otomatis sirkulas darah Anda akan mejadi lebih baik, jantung akan terlatih untuk terus memompa darah sehingga dapat meningkatkan zat besi dalam darah dan menjadikan tubuh lebih sehat serta mengurangi Anda menderita penyakit jantung.

2. Membakar kalori

Mendonorkan darah secara teratur akan membantu Anda membakar kalori dalam tubuh, tidak percaya? Bayangkan saja, ketika darah yang Anda donorkan sebanyak 450 ml, maka Anda pun kehilangan sekitar 650 kalori.

3. Menurunkan risiko kanker

Selain membantu membakar kalori, mendonorkan darah pun dapat menurnkan risiko terjadinya kanker. Termasuk kanker hati, paru-paru, usus besar, perut, dan kanker tenggorokan.

4. Meningkatkan produksi darah

Manfaat mendonorkan darah secara teratur dapat membantu merangsang produksi sel-sel darah baru. Proses mendonorkan darah ini, akan membantu tubuh tetap sehat dan bekerja lebih efisien.

5. Pikiran lebih stabil

Apakah Anda tahu bahwa mendonorkan darah secara rutin dapat membantu Anda menjaga pikiran tetap stabil? Inilah faktanya. Dengan mendonorkan darah, dapat membuat Anda merasa lebih bahagia dan damai. Bahagia karena dapat menolong sesama dan damai dengan tubuh sendiri ternyata juga dapat meningkatkan kesehatan secara psikologis.

6. Bagian dari periksa kesehatan

Mendonorkan darah juga dapat digunakan sebagai uji pemeriksaan kesehatan diri sendiri. Ketika darah yang Anda miliki berada di dalam kantong darah dan diperiksa di laboratorium, maka tim medis akan melihat apakah Anda menderita suatu penyakit tertentu atau tidak. Sebab jika Anda negatif dari segala jenis penyakit, maka darah yang Anda miliki dapat disumbangkan untuk mereka yang membutuhkan. Jika tidak, maka Anda akan diberitahu apa yang sebenarnya sedang terjadi.

7. Menjadi lansia yang sehat

Banyak orang tua yang memiliki kesehatan cukup baik dan prima di usianya yang telah lanjut tersebut. Ini sebabkan karena mereka senantiasa menyumbangkan darahnya sejak muda sampai mereka tua.

8. Menurunkan kolesterol

Manfaat kesehatan lain dari mendonorkan darah secara rutin adalah menurunkan kolesterol, sehingga dapat membantu Anda dalam mengurangi kadar kolesterol dalam tubuh. Dengan melakukan donor darah, kolesterol yang ada di dalam darah secara tidak langsung akan berkurang bersamaan dengan keluarnya darah yang lama. Ini sangat bagus untuk menurunkan kolesterol.

Jadi, setelah kita mengetahui berbagai macam manfaat donor darah, masihkah ragu untuk melakukannya? Mari bersama-sama menjadikan diri kita bermanfaat bagi orang lain, karena hidup ini hanya sekali. 😊

Penulis Donor Darah di PMI Bekasi