Robot Penghindar Halangan
Robot Penghindar Halangan (obstacle avoidance), adalah sebuah robot yang mempunyai kemampuan untuk menghindari halangan atau rintangan yang ada didepan kanan dan kiri dengan menghindar ke arah lain. Robot ini berbentuk mobil dan menggunakan roda - roda untuk menggerakkannya.
Robot ini terdiri dari komponen - komponen elektronik diantaranya, mikrokontroler AT89C2051 sebagai pengendali,sensor Infra Merah, karena sensor ini memiliki kemampuan untuk mendeteksi halangan dengan cukup baik tanpa adanya kontak langsung dan sangat murah harganya, IC 74LS14 sebagai penghasil frekuensi 40 kHz, IC LM567 sebagai penerima pemancar Infra merah, pengendali motor L293D sebagai driver motor DC. Sensor untuk menghindari halangan menggunakan sensor Infra Merah. Dan dua buah motor Dc digunakan untuk menggerakkan robot tersebut.
Robot ini menggunakan sensor Infra Merah untuk mendeteksi ada atau tidak adanya halangan, dan sebagai pembangkit frekuensi 40 kHz digunakan IC 74LS14. Kedua roda bergerak secara diferensial yang digerakkan oleh dua buah motor Dc. Sebagai penguat sinyal yang diterima oleh bagian penerima (Rx) dari sensor Infra Merah digunakan Tone detectorop LM567. Dan untuk menguatkan sinyal keluaran penguat digunakan IC 74LS14 agar sinyal betul - betul saat high 4,8 Voly dan saat Low o Volt, sensor ini maksimal bisa mendeteksi penghalang pada jarak 40 Cm, tergantung kita mau di setel pada jarak berapa.
CARA KERJA :
Tekan switch power dari switch push button untuk memulai proses Start, Sensor IR1 sebagai sensor depan akan mendeteksi apakah ada halangan, jika tidak ada maka motor A dan B akan maju sampai ada halangan yang mengaktifkan sensor depan yang mengakibatkan motor berhenti sesaat dan kemudian mundur sesaat dan memutar ke kiri atau kanan kemudian maju,Sedangkan saat sensor IR2 sebagai sensor kanan, jika sensor ini mendeteksi halangan maka Motor kiri berhenti dan Motor kanan berputar maju sehingga robot akan berbelok ke kiri dan jika sensor IR3 yang berfungsi sebagai sensor kiri bila ada halangan akan berbuat demikian sehingga robot akan berbelok ke kanan, demikian seterusnya.
Sunday, January 3, 2010
Purging of Boiler Circulating Water Pump
1.5 Purging of Boiler Circulating Water Pump
1. Verify closed cooling water is aligned to boiler circulating water pumps prior to filling:
a) Closed cooling water supply valve SG03-9 (21) open
b) Closed cooling water control valve inlet isolation valve SG03-11 (22) open
c) Closed cooling water control valve SG03-1 (66) in Auto
d) Bypass SG03-216 closed
e) Emergency thermal barrier cooling valve SG03-2 closed
2. Verify boiler circulating pump thermal barrier valves are locked open:
a) Boiler circulating pump 11/21
i) Thermal barrier supply valve SG03-20
ii) Thermal barrier return valve SG03-28 (16)
b) Boiler circulating pump 12/22
i) Thermal barrier supply valve SG03-21
ii) Thermal barrier return valve SG03-29 (16)
c) Boiler circulating pump 13/23
i) Thermal barrier supply valve SG03-22
ii) Thermal barrier return valve SG03-30 (16)
d) Boiler circulating pump 14/24
i) Thermal barrier supply valve SG03-23
ii) Thermal barrier return valve SG03-31 (16)
3. Verify boiler circulating pumps closed cooling water return header is aligned as follows:
a) Closed cooling water return control valve inlet isolation valve SG03-15 (62) is open
b) Closed cooling water return control valve inlet SG03-3 (67) in Auto
c) Closed cooling water return control valve outlet isolation valve SG03-17 (62) is open
d) Bypass SG03-217 closed
e) Emergency thermal cooling drain SG03-4 closed (vlv 14 open)
4. Close or Verify Closed boiler circulating pump suction valve as appropriate:
a) Boiler circulating pump 11/21 suction valve SG03-5 (2)
b) Boiler circulating pump 12/22 suction valve SG03-6 (2)
c) Boiler circulating pump 13/23 suction valve SG03-7 (2)
d) Boiler circulating pump 14/24 suction valve SG03-8 (2)
5. Close or Verify Closed boiler circulating pump discharge valve as appropriate:
a) Boiler circulating pump 11/21 discharge valves SG03-126 (3), and SG03-127 (3)
b) Boiler circulating pump 12/22 discharge valves SG03-128 (3), and SG03-129 (3)
c) Boiler circulating pump 13/23 discharge valves SG03-130 (3), and SG03-131 (3)
d) Boiler circulating pump 14/24 discharge valves SG03-132 (3), and SG03-133 (3)
6. Close boiler water circulating pump bypass valves as appropriate:
a) Boiler circulating pump 11/21 bypass valves SG03-94 (5), and SG03-106 (6)
b) Boiler circulating pump 12/22 bypass valves SG03-95 (5), and SG03-108 (6)
c) Boiler circulating pump 13/23 bypass valves SG03-96 (5), and SG03-110 (6)
d) Boiler circulating pump 14/24 bypass valves SG03-97 (5), and SG03-112 (6)
7. Open drain valves (44) and (18).
8. Verify Closed Strainer drain valves SG03-44, and SG03-45.
9. Close boiler circulating pump motor cavity isolation valve:
a) Boiler circulating pump 11/21 motor cavity valve SG03-246 (10A)
b) Boiler circulating pump 12/22 motor cavity valve SG03-247 (10A)
c) Boiler circulating pump 13/23 motor cavity valve SG03-248 (10A)
d) Boiler circulating pump 14/24 motor cavity valve SG03-249 (10A)
10. Close boiler circulating pump motor cavity cooling water valve:
a) Boiler circulating pump 11/21 motor cavity cooling water SG03-250
b) Boiler circulating pump 12/22 motor cavity cooling water SG03-251
c) Boiler circulating pump 13/23 motor cavity cooling water SG03-252
d) Boiler circulating pump 14/24 motor cavity cooling water SG03-253
11. Open bypass valves and vent valves:
a) SG03-102 (5A), SG03-107 (6A), (7), and (57)
b) SG03-103 (5A), SG03-109 (6A), (7), and (57)
c) SG03-103 (5A), SG03-111 (6A), (7), and (57)
d) SG03-104 (5A), SG03-113 (6A), (7), and (57)
12. Verify low pressure fill spool piece is removed and outlet isolation valve SG03-39 (50) is closed.
13. Open boiler circulating pumps high pressure fill isolation valve SG03-36 (38).
14. Open boiler circulating pumps fill strainer inlet (SG03-42) isolation valve.
15. Blowdown fill line through fill strainer drain valves SG03-44, and SG03-45.
16. Open boiler circulating pumps fill outlet (SG03-43) isolation valves.
1. Verify closed cooling water is aligned to boiler circulating water pumps prior to filling:
a) Closed cooling water supply valve SG03-9 (21) open
b) Closed cooling water control valve inlet isolation valve SG03-11 (22) open
c) Closed cooling water control valve SG03-1 (66) in Auto
d) Bypass SG03-216 closed
e) Emergency thermal barrier cooling valve SG03-2 closed
2. Verify boiler circulating pump thermal barrier valves are locked open:
a) Boiler circulating pump 11/21
i) Thermal barrier supply valve SG03-20
ii) Thermal barrier return valve SG03-28 (16)
b) Boiler circulating pump 12/22
i) Thermal barrier supply valve SG03-21
ii) Thermal barrier return valve SG03-29 (16)
c) Boiler circulating pump 13/23
i) Thermal barrier supply valve SG03-22
ii) Thermal barrier return valve SG03-30 (16)
d) Boiler circulating pump 14/24
i) Thermal barrier supply valve SG03-23
ii) Thermal barrier return valve SG03-31 (16)
3. Verify boiler circulating pumps closed cooling water return header is aligned as follows:
a) Closed cooling water return control valve inlet isolation valve SG03-15 (62) is open
b) Closed cooling water return control valve inlet SG03-3 (67) in Auto
c) Closed cooling water return control valve outlet isolation valve SG03-17 (62) is open
d) Bypass SG03-217 closed
e) Emergency thermal cooling drain SG03-4 closed (vlv 14 open)
4. Close or Verify Closed boiler circulating pump suction valve as appropriate:
a) Boiler circulating pump 11/21 suction valve SG03-5 (2)
b) Boiler circulating pump 12/22 suction valve SG03-6 (2)
c) Boiler circulating pump 13/23 suction valve SG03-7 (2)
d) Boiler circulating pump 14/24 suction valve SG03-8 (2)
5. Close or Verify Closed boiler circulating pump discharge valve as appropriate:
a) Boiler circulating pump 11/21 discharge valves SG03-126 (3), and SG03-127 (3)
b) Boiler circulating pump 12/22 discharge valves SG03-128 (3), and SG03-129 (3)
c) Boiler circulating pump 13/23 discharge valves SG03-130 (3), and SG03-131 (3)
d) Boiler circulating pump 14/24 discharge valves SG03-132 (3), and SG03-133 (3)
6. Close boiler water circulating pump bypass valves as appropriate:
a) Boiler circulating pump 11/21 bypass valves SG03-94 (5), and SG03-106 (6)
b) Boiler circulating pump 12/22 bypass valves SG03-95 (5), and SG03-108 (6)
c) Boiler circulating pump 13/23 bypass valves SG03-96 (5), and SG03-110 (6)
d) Boiler circulating pump 14/24 bypass valves SG03-97 (5), and SG03-112 (6)
7. Open drain valves (44) and (18).
8. Verify Closed Strainer drain valves SG03-44, and SG03-45.
9. Close boiler circulating pump motor cavity isolation valve:
a) Boiler circulating pump 11/21 motor cavity valve SG03-246 (10A)
b) Boiler circulating pump 12/22 motor cavity valve SG03-247 (10A)
c) Boiler circulating pump 13/23 motor cavity valve SG03-248 (10A)
d) Boiler circulating pump 14/24 motor cavity valve SG03-249 (10A)
10. Close boiler circulating pump motor cavity cooling water valve:
a) Boiler circulating pump 11/21 motor cavity cooling water SG03-250
b) Boiler circulating pump 12/22 motor cavity cooling water SG03-251
c) Boiler circulating pump 13/23 motor cavity cooling water SG03-252
d) Boiler circulating pump 14/24 motor cavity cooling water SG03-253
11. Open bypass valves and vent valves:
a) SG03-102 (5A), SG03-107 (6A), (7), and (57)
b) SG03-103 (5A), SG03-109 (6A), (7), and (57)
c) SG03-103 (5A), SG03-111 (6A), (7), and (57)
d) SG03-104 (5A), SG03-113 (6A), (7), and (57)
12. Verify low pressure fill spool piece is removed and outlet isolation valve SG03-39 (50) is closed.
13. Open boiler circulating pumps high pressure fill isolation valve SG03-36 (38).
14. Open boiler circulating pumps fill strainer inlet (SG03-42) isolation valve.
15. Blowdown fill line through fill strainer drain valves SG03-44, and SG03-45.
16. Open boiler circulating pumps fill outlet (SG03-43) isolation valves.
Mesin Bubut
MESIN BUBUT KONVENSIONAL
Mesin bubut konvensional adalah mesin perkakas atau mesin bubut biasa yang memproduksi benda benda bentuk silindris.Mekanisme gerakan eretan,memasang eretan melintang dan eretan atas di layani dengan hendel hendel secara manual(dengan tangan),baik secara otomatis maupun langsung.
Macam macam pekerjaan yang dapat di lakukan dengan mesin bubut konvensional adalah;
-membubut rata
-membubut bertingkat
-mengebor dengan membubut dalam
-membuat rigi
-membuat ulir segi tiga luar dan dalam
-membuat segi enam luar dan dalam
-membuat tirus dan ulir tirus
-membuat copy
-membuat eksentrik
A.PERSIAPAN MEMBUBUT
jika menerima order /job,untuk pekerjaan membubut,kita tidak bisa langsung memotong benda kerja lalu kita bentuk langsung,tetapi harus kita pelajari terlebih dahulu,beberapa hal yang harus kita pelajari sebelum melakukan pembubutan antara lain:)
-mempelajari gambar kerja,untuk mendapat bentuk dan ukurannya
-bahan yang harus kita ketahui(lunak,sedang dan atau keras)
-kwalitas bubutan yang diinginkan(halus/kasar)
-pahat yang cocok kita gunakan(baik bentuk maupun bahan dari bahannya)
-alat bantu yang di perlukan(alat pembawa,penyangga/penyangga tetap/brill)
-apa mesin hoes bekerja ganda atau tunggal
untuk gerakan eretan kecepatan mesin(putaran gigi pada roda2 gigi pengganti yang halus di pasang pada waktu melakukan pembubutan tertentu
Mesin bubut konvensional adalah mesin perkakas atau mesin bubut biasa yang memproduksi benda benda bentuk silindris.Mekanisme gerakan eretan,memasang eretan melintang dan eretan atas di layani dengan hendel hendel secara manual(dengan tangan),baik secara otomatis maupun langsung.
Macam macam pekerjaan yang dapat di lakukan dengan mesin bubut konvensional adalah;
-membubut rata
-membubut bertingkat
-mengebor dengan membubut dalam
-membuat rigi
-membuat ulir segi tiga luar dan dalam
-membuat segi enam luar dan dalam
-membuat tirus dan ulir tirus
-membuat copy
-membuat eksentrik
A.PERSIAPAN MEMBUBUT
jika menerima order /job,untuk pekerjaan membubut,kita tidak bisa langsung memotong benda kerja lalu kita bentuk langsung,tetapi harus kita pelajari terlebih dahulu,beberapa hal yang harus kita pelajari sebelum melakukan pembubutan antara lain:)
-mempelajari gambar kerja,untuk mendapat bentuk dan ukurannya
-bahan yang harus kita ketahui(lunak,sedang dan atau keras)
-kwalitas bubutan yang diinginkan(halus/kasar)
-pahat yang cocok kita gunakan(baik bentuk maupun bahan dari bahannya)
-alat bantu yang di perlukan(alat pembawa,penyangga/penyangga tetap/brill)
-apa mesin hoes bekerja ganda atau tunggal
untuk gerakan eretan kecepatan mesin(putaran gigi pada roda2 gigi pengganti yang halus di pasang pada waktu melakukan pembubutan tertentu
Labels:
pemesinan
Wednesday, December 30, 2009
INJECTION MOLDING TERMS
Air Hole : A hole in a molding by air or gas trapped in the melt during solidification.
Air Traps : Converging flow fronts surround and trap a bubble of air or gas which will cause a surface blemish in the part .
Bottom Plate: The plate fixed to the moving half of die and facilitates attachment to the injection molding machine .
Cavity : The mold or die impression that gives a molding its external shape.
Core: Male potion of the mould, which forms internal shape of the component.
Cooling: Channels located within the body of a mold through which a cooling Channels medium is circulated to control the mold surface temperature.
Cycle Time : The time required by an injection molding system to mold a part and return to its original position/state.
Draft : An angle or taper on the surfaces of a pattern or insert that facilitates removal of parts from a mold or die.
Edge gate:Entrance to the part from the runner located on the parting line.
Ejector: A mechanism that pushes the solidified molding out of the die.
Feeding: In a molding, providing plastic melt to a region undergoing solidification, usually at a rate sufficient to fill the mold cavity ahead of the solidification front and to compensate for any shrinkage accompanying solidification.
Flash: A thin section of plastic formed at the parting surface.
Temperature :The material temperature at each point as that point was filled. The result shows the changes in the temperature of the flow front during filling.
Gate: Is a channel or orifice connecting the runner with the impression.
Guide Pillars : Cylindrical members meant to align the mold halves and are & Bushes made of hardened steel. Bushes are meant for wear resistance between housing and pillars.
Hesitation : Hesitation is a surface defect that results from the stagnation of polymer melt flow over a thin-sectioned area, or an area of abrupt thickness variation.
Housing : A metal block which houses inserts (core and cavity), pillars, return pins etc.
Injection: The process of forcing molten melt under pressure into molds.
Injection Location :The injection location is the place where the molten plastic is forced into the mold cavity.
Insert : A part formed from a second material, usually a metal that is placed in the molds and appears as an integral structural part of the final molding.
Locating ring: Is a circular member fitted to top-plate of the mould. Its purpose is to register the mould in its correct position on the injection machine.
Molding: Plastic part molded to the required shape by pouring or injecting melt into a mold, as distinct from one shaped by cutting or a mechanical working process.
Mold Temperature: The temperature at which the mold is maintained. Often the most important benefit of raising mold temperature is that it allows a slower injection rate without the plastic getting too cold.
Nozzle: Hollow metal hose screwed into the extrusion end of the heating cylinder of an injection machine designed to form a seal under pressure between the cylinder and the mold.
Parting Plane : In molding, the dividing plane between mold halves.
Runner: A Channel through which melt flows from one receptacle to another.
Sprue Bush: A bush with a tapered hole, which connects nozzle with runner.
Tie Bar: A bar-shaped connection added to a casting to prevent distortion caused by uneven contraction between two separate members of a casting.
Vent : A small opening or passage that facilitates the escape of gases when the melt is fills the die cavity.
Air Traps : Converging flow fronts surround and trap a bubble of air or gas which will cause a surface blemish in the part .
Bottom Plate: The plate fixed to the moving half of die and facilitates attachment to the injection molding machine .
Cavity : The mold or die impression that gives a molding its external shape.
Core: Male potion of the mould, which forms internal shape of the component.
Cooling: Channels located within the body of a mold through which a cooling Channels medium is circulated to control the mold surface temperature.
Cycle Time : The time required by an injection molding system to mold a part and return to its original position/state.
Draft : An angle or taper on the surfaces of a pattern or insert that facilitates removal of parts from a mold or die.
Edge gate:Entrance to the part from the runner located on the parting line.
Ejector: A mechanism that pushes the solidified molding out of the die.
Feeding: In a molding, providing plastic melt to a region undergoing solidification, usually at a rate sufficient to fill the mold cavity ahead of the solidification front and to compensate for any shrinkage accompanying solidification.
Flash: A thin section of plastic formed at the parting surface.
Temperature :The material temperature at each point as that point was filled. The result shows the changes in the temperature of the flow front during filling.
Gate: Is a channel or orifice connecting the runner with the impression.
Guide Pillars : Cylindrical members meant to align the mold halves and are & Bushes made of hardened steel. Bushes are meant for wear resistance between housing and pillars.
Hesitation : Hesitation is a surface defect that results from the stagnation of polymer melt flow over a thin-sectioned area, or an area of abrupt thickness variation.
Housing : A metal block which houses inserts (core and cavity), pillars, return pins etc.
Injection: The process of forcing molten melt under pressure into molds.
Injection Location :The injection location is the place where the molten plastic is forced into the mold cavity.
Insert : A part formed from a second material, usually a metal that is placed in the molds and appears as an integral structural part of the final molding.
Locating ring: Is a circular member fitted to top-plate of the mould. Its purpose is to register the mould in its correct position on the injection machine.
Molding: Plastic part molded to the required shape by pouring or injecting melt into a mold, as distinct from one shaped by cutting or a mechanical working process.
Mold Temperature: The temperature at which the mold is maintained. Often the most important benefit of raising mold temperature is that it allows a slower injection rate without the plastic getting too cold.
Nozzle: Hollow metal hose screwed into the extrusion end of the heating cylinder of an injection machine designed to form a seal under pressure between the cylinder and the mold.
Parting Plane : In molding, the dividing plane between mold halves.
Runner: A Channel through which melt flows from one receptacle to another.
Sprue Bush: A bush with a tapered hole, which connects nozzle with runner.
Tie Bar: A bar-shaped connection added to a casting to prevent distortion caused by uneven contraction between two separate members of a casting.
Vent : A small opening or passage that facilitates the escape of gases when the melt is fills the die cavity.
MATERIALS USED IN MOULD MANUFACTURING
1) Mild Steel (C-45)
This steel is relatively cheap. The steel is soft and cannot be fully hardened. It is extensively used to manufacture plates like top plate, bottom plate, ejector plate, core and cavity housings, spacers etc. It has high tensile strength. This steel has good shock resisting and machining properties.
2) Case hardening Steel (17MnCr95)
Initially these steels do not have sufficient carbon content essential for heat treatment process. Carbon is induced into the outer layer of the steel to convert into high carbon steels with carbon content ranging from 0.9 to 1.2%. When heat-treated achieve a hardness up to 50 – 55 HRC on the surface and retains a soft tough core. This is used for finger cam, guide pillars, guide bushes, ejector guide pillars and bushes and push back pins, as they require adequate strength as well as wear and resistance properties.
Composition:
Carbon-0.17%, Silicon-0.25%, Manganese- 1.25%, Chromium-1.15%, Sulphur-0.035%
3) Hot Die Steel (T35Cr5MoV1)
This steel has alloying element like carbon, which increases strength, elasticity and hardness. Chromium improves corrosion resistance, toughness and hardenability. Molybdenum improves creep strength and vanadium, which oxidizes and promotes fine-grained structures which is very helpful in manufacturing core and cavity of the mould. This material is hardened up to 48 – 50 HRC. This type of steel is used for core and cavity inserts, core and cavity sub inserts and side core pins.
Composition:
Carbon-0.37%, Silicon-0.25%, Molybdenum-1.2%, Vanadium- 1.0%, Chromium-5.0%
4. Oil Hardened Non Shrinkable Steel (T110W2CR5)
These steels tend to have good hardening properties and have less dimensional changes during heat treatment. They are relatively inexpensive, readily available, have good machinability, good resistance to decarburization and have a high carbon content to provide good wear resistance. The depth of hardness is homogeneous. This material is hardened up to 48 – 50 HRC. This steel is used for guide rails, wear plates, wedges, side core holder, sprue and sprue puller bushes.
Composition:
Carbon-0.95%, Silicon-0.35%, Tungsten-0.5%, Manganese- 1.20%, Chromium-0.5%
This steel is relatively cheap. The steel is soft and cannot be fully hardened. It is extensively used to manufacture plates like top plate, bottom plate, ejector plate, core and cavity housings, spacers etc. It has high tensile strength. This steel has good shock resisting and machining properties.
2) Case hardening Steel (17MnCr95)
Initially these steels do not have sufficient carbon content essential for heat treatment process. Carbon is induced into the outer layer of the steel to convert into high carbon steels with carbon content ranging from 0.9 to 1.2%. When heat-treated achieve a hardness up to 50 – 55 HRC on the surface and retains a soft tough core. This is used for finger cam, guide pillars, guide bushes, ejector guide pillars and bushes and push back pins, as they require adequate strength as well as wear and resistance properties.
Composition:
Carbon-0.17%, Silicon-0.25%, Manganese- 1.25%, Chromium-1.15%, Sulphur-0.035%
3) Hot Die Steel (T35Cr5MoV1)
This steel has alloying element like carbon, which increases strength, elasticity and hardness. Chromium improves corrosion resistance, toughness and hardenability. Molybdenum improves creep strength and vanadium, which oxidizes and promotes fine-grained structures which is very helpful in manufacturing core and cavity of the mould. This material is hardened up to 48 – 50 HRC. This type of steel is used for core and cavity inserts, core and cavity sub inserts and side core pins.
Composition:
Carbon-0.37%, Silicon-0.25%, Molybdenum-1.2%, Vanadium- 1.0%, Chromium-5.0%
4. Oil Hardened Non Shrinkable Steel (T110W2CR5)
These steels tend to have good hardening properties and have less dimensional changes during heat treatment. They are relatively inexpensive, readily available, have good machinability, good resistance to decarburization and have a high carbon content to provide good wear resistance. The depth of hardness is homogeneous. This material is hardened up to 48 – 50 HRC. This steel is used for guide rails, wear plates, wedges, side core holder, sprue and sprue puller bushes.
Composition:
Carbon-0.95%, Silicon-0.35%, Tungsten-0.5%, Manganese- 1.20%, Chromium-0.5%
EFFECT OF ALLOYING ELEMENTS
a) Effect of Carbon:
Carbon makes the steel hard and more wear resistance. Steels having less than 0.3% carbon cannot be hardened. Beyond 3% carbon steels can be through hardened. Hardness of steel increases upon 0.8% carbon and beyond that, hardness does not increase but wear resistance increase.
b) Effect of Chromium:
Chromium increases hardenability, toughness and wear resistance. Chromium causes greater hardness penetration.
c) Effect of Nickel:
It improves toughness and wear resistance. When used with increasing hardness element like chromium it lowers hardening temperature and tends the steel towards oil hardening. Higher the percentage of nickel along with the chromium results in rust free steel – stainless steel.
d) Effect of manganese:
It helps to make the steel sound while casting as an ingot. It lowers the critical point and hence the hardenability by 1.5%. Addition of more manganese increases hardenability. The depth of penetration of hardness increases.
e) Effect of Tungsten:
It increases wear resistance when added in fairly large quantity (1.5%). 12 – 20% tungsten with chromium gives a new property names as “Red Hardness”. It unites with the carbon to form tungsten – carbide, which attains very high hardness and wear resistance.
f) Effect vanadium:
It helps in obtaining fine-grained steel. It increases red hardness property. Small percentage increases tensile strength, yield strength, hardness and wear resistance.
g) Effect of Molybdenum:
It has both properties of chromium and tungsten. Like chromium it increases hardness penetration and inclines the steel towards oil or oil hardening. Like tungsten it increase wear resistance and red hardness. 5 – 12% with chromium, tungsten and vanadium forms a molybdenum based HSS material.
Carbon makes the steel hard and more wear resistance. Steels having less than 0.3% carbon cannot be hardened. Beyond 3% carbon steels can be through hardened. Hardness of steel increases upon 0.8% carbon and beyond that, hardness does not increase but wear resistance increase.
b) Effect of Chromium:
Chromium increases hardenability, toughness and wear resistance. Chromium causes greater hardness penetration.
c) Effect of Nickel:
It improves toughness and wear resistance. When used with increasing hardness element like chromium it lowers hardening temperature and tends the steel towards oil hardening. Higher the percentage of nickel along with the chromium results in rust free steel – stainless steel.
d) Effect of manganese:
It helps to make the steel sound while casting as an ingot. It lowers the critical point and hence the hardenability by 1.5%. Addition of more manganese increases hardenability. The depth of penetration of hardness increases.
e) Effect of Tungsten:
It increases wear resistance when added in fairly large quantity (1.5%). 12 – 20% tungsten with chromium gives a new property names as “Red Hardness”. It unites with the carbon to form tungsten – carbide, which attains very high hardness and wear resistance.
f) Effect vanadium:
It helps in obtaining fine-grained steel. It increases red hardness property. Small percentage increases tensile strength, yield strength, hardness and wear resistance.
g) Effect of Molybdenum:
It has both properties of chromium and tungsten. Like chromium it increases hardness penetration and inclines the steel towards oil or oil hardening. Like tungsten it increase wear resistance and red hardness. 5 – 12% with chromium, tungsten and vanadium forms a molybdenum based HSS material.
SELECTION OF TOOL STEEL
The selection of tool steel is very important for any tool upon which the development and economical operation of the process depends. Care should be taken especially while injection moulding plastics, which may affect the factors like mould life, quality, cost of mould and machine etc.
The steel used in the manufacture of mould varies depending on the applications. Proper material selection and proper combination of alloys in varying percentages are required for finished moulds.
Following properties are desired from the steels used in mold making
The steel used in the manufacture of mould varies depending on the applications. Proper material selection and proper combination of alloys in varying percentages are required for finished moulds.
Following properties are desired from the steels used in mold making
- Characteristics permitting economical machining
- Capacity for heat treatment without problems
- Ease of polishing
- High Wear resistance
- High Thermal conductivity
- Good Corrosion resistance
- Good Toughness
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