Manufacturing process of engine valve plant One Month Industrial Training Report
In partial fulfillment for the award of the degree of BACHELOR OF TECHNOLOGY IN MECHANICAL ENGINEERING At
Hi-Tech Hi-Tech Institute of Engineering Engineer ing & Technology, Ghaziabad Affiliated to U.P Technical University, Lucknow
Submitted to:-
Submitted by:-
Mechanical department HIET GZB
Ashwani kumar Uni. Roll;no 0822040403
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Kumar, student Of B.tech 3rd year mechanical This is to certify that Mr. Ashwani Kumar, engineering from,Hi-Tech from, Hi-Tech Institute Of Engineering And Technology Ghaziabad (U. P.) has successfully done his vocational training in the E.V Forge shop of Shri Ram Pistons & Rings Ghaziabad. Ghaziabad. During his training training period period in in Shri Ram Pistons & Rings th th 2010, he has prepared from 21 June 2010 to 26 July 2010, prepared a training report report consisting of the details of various shops. He possessed excellent conduct and has successfully completed his training. I wish him great success in his future life.
Date: Date: Place: Ghaziabad
Mr Vikas Arora Shri Ram Pistons & Rings Ltd Gzb
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Kumar, student Of B.tech 3rd year mechanical This is to certify that Mr. Ashwani Kumar, engineering from,Hi-Tech from, Hi-Tech Institute Of Engineering And Technology Ghaziabad (U. P.) has successfully done his vocational training in the E.V Forge shop of Shri Ram Pistons & Rings Ghaziabad. Ghaziabad. During his training training period period in in Shri Ram Pistons & Rings th th 2010, he has prepared from 21 June 2010 to 26 July 2010, prepared a training report report consisting of the details of various shops. He possessed excellent conduct and has successfully completed his training. I wish him great success in his future life.
Date: Date: Place: Ghaziabad
Mr Vikas Arora Shri Ram Pistons & Rings Ltd Gzb
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ACKNOWLEDGMENT I take great pleasure to acknowledge the people who have been involved in completion of my project at different stages. It has been a privilege working with all those who have been a part of this success story.
I give the credit of fruition of my project to my guide Mr.Vikash Arora, Arora, of shri ram piston and ring limited. limited. It was his support that I got valuable inputs towards my project. I would also thank each member of Provisioning team at Shri Ram Piston & Ring Limited, Limited, who always provided their valuable insights and helped me in completion of allotted task. Lastly, I would like to pay my sincere regards to each and everyone who directly or indirectly helped me in my completion of the project and making it a success.
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CONTENTS
1.
INTRODUCTION OF SHRI RAM PISTONS & RINGS LIMITED
2.
INTRODUCTION ABOUT ENGINE VALVE PLANT
3.
ABOUT FUNCTION OF ENGINE VALVE IN I.C ENGIN
4.
BASIS OF MATERIAL SLECTION
5.
ABOUT MATERIAL COMPOSTION
6.
CLASSIFICATION OF VALVE
7.
PROSSES OPERATION SEQUENCE
8.
BRIEF INTRODUCTION ABOUT EACH PROCESS
RAW MATERIAL FRICTION WELDING UPSETTING FORGING HEAT TREATMENT SHOT BLASTING STRIGHTENING STEAM END CUT STELLITE GROOVING SEAT SETELLITING TIP DRILLING TIP SETELLITING END GRINDING ULTRASONIC INSPECTION POST OD TRAINING MACHINE SHOP
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INTRODUCTION OF SHRI RAM PISTONS & RINGS LIMITED Company Profile
Shriram Pistons & Rings Ltd ( SPRL ).Is a part of well Known Shriram Group of Companies.SPRL is presently engaged in manufacturing of I.C Engine component such as Pistons, Rings, Gudgeon pins,Engine Valves & Gears in collaboration with world leaders like Kolbenschmidt of Germany&Honda Foundry of Japan for Pistons ,Riken Corporation of Japan for Rings & Fuzi Oozx of Japan for Engine
valves. Company’s product under USHA brand name are exported to over 60 countries world wide including reputed OEM’s.The company has QS -9000 & ISO/TS-16949 & EMS-14001, OHSAS-18001 accreditations under its belt & has bagged the TPM(Total Productive Maintenance) Excellence award from JIPM, Japan.
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Company Achievement's
1993 Commissioning of E.V plant.
1994 ISO-9001 for Piston, Pin ,Ring Plant.
1995 Commissioning of Automatic line for diesel pistons .
1996 Exclusive supplier status with T.C.L.
1997 ISO-9001 for E.V plant
1998 Best vender Award (Maruti Suzuki).
1999 QS-9000 : .
Best supplier award (T.C.L)
Export performance award. ACMA quality award
2001 ISO-14001
2003 TS-16949 & OHSAS-18001 Certification.
2004 Comm.of automatic line for petrol piston& TPM Excellence award.
2007 preparation for TPM special award.
2008-09 best quality vendor award from tata moters
2009-10 best expoter award from FIEO
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Company Policy
T.P.M Policy
“Zero failure”, “Zero Defect”, “Zero Accident” through introduction of TPM, with involvement of all employees. Quality Policy Total customer satisfaction through Quality Management & continuous improvement.
Environmental Policy
Continual improvement in environmental performance through prevention, monitoring and control of pollution and improving environmental bench marks for sustainable growth.
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INTRODUCTION ABOUT ENGINE VALVE PLANT Engine valve plant related to manufacturing and machining of the engine valve.first all the manufacturing process are completed by the prosses operation sequence then manufactured product goes to machine shop for finishing of the product. Engine valve plant is divided into two part
Engine valve forge shop Engine valve machine shop
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Engine valve forging plant related to manufacturing of the Engine valve forge shop product.In this plant all the process such as forging, upsetting and other manufacturing process are completed.
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Engine valve machine shop Engine valve machine shop related to related to the finishing of product and production of engine valve is completed.
ABOUT FUNCTION OF ENGINE VALVE IN I.C ENGINE
FUNCTION - Inlet valve allow the fresh charge of air-fuel mixture to enter the cylinder bore.Exhaust valve permits the burnt gases to escape from the cylinder bore at proper timing. Engine valves are located in the cylinder head. The main function of the engine valves is to let air in and out of the cylinders. That air is used to help ignite the fuel which will drive the pistons up and down. There are two types of engine valves; intake and exhaust valves. The intake valves of course let air in, and the exhaust valves let exhaust air out. The more air you can move air in and out of the engine the more efficient, and therefor power the engine will have. This is why the engine valve plays a pretty critical role in an engines performance.
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Basis of Material Selection
To understand valve alloys, you need to know something about basic metallurgy. There are essentially two basic types of steel used to make valves. One is "martensitic" steel and the other is "austenitic" steel. The difference is in the microstructure of the steel and how the various ingredients in the alloy interact when the molten steel is cast and cooled. This affects not only the hardness and strength of the steel, but also its corrosion resistance and magnetic properties. As a rule, martensitic steels are magnetic while austenitic steels are non-magnetic.
In martensitic steel, the steel is "quenched" (cooled) very quickly from a molten state to freeze the grain structure in a particular configuration. Under a microscope, the grain structure has a needle-like (acicular) appearance. This makes the steel very hard but also brittle. Reheating and cooling the ste el (a process called "tempering") allows some of the martensite crystals to rearrange themselves into other grain structures which are not as hard or brittle. By carefully controlling the heat treatment and quenching process, the hardness and tensile strength of the steel can be fine tuned to achieve the desired properties.
Steel alloys with a martensitic grain structure typically have a high hardness at room temperature (35 to 55 Rockwell C) after tempering, which improves strength and wear resistance. These characteristics make this type of steel a good choice for applications such as engine valves. But as the temperature goes up, martensitic steel loses hardness and strength. Above 1000° F or so, low carbon alloy martensitic steel loses too much hardness and strength to hold up very well. For this reason, low carbon alloy martensitic steel is only used for intake valves, not exhaust valves. Intake valves are cooled by the incoming air/fuel mixture and typically run around 800° to 1000° F, while exhaust valves are constantly blasted by hot exhaust gases and usually operate at 1200 to 1450° F or higher.
To increase high temperature strength and corrosion resistance, various elements may be added to the steel. On some passenger car and light truck engines, the original equipment intake valves are 1541 carbon steel with manganese added to improve corrosion ix
resistance. For higher heat applications, a 8440 alloy may be used that contains chromium to add high temperature strength. For many late model engines (and performance engines), the intake valves are made of an alloy called "Silchrome 1" (Sil 1) that contains 8.5 percent chromium.
Exhaust valves may be made from a martensitic steel with chrome and silicon alloys, or a two-piece valve with a stainless steel head and martensitic steel stem. On applications that have higher heat requirements, a stainless martensitic alloy may be used. Stainless steel alloys, as a rule, contain 10 percent or more chromium. The most popular materials for exhaust valves, however, are austenitic stainless steel alloys such as 21-2N and 21-4N. Austenite forms when steel is heated above a certain temperature which varies depending on the alloy. For many steels, the austenitizing temperature ranges from 1600° to 1675° F, which is about the temperature where hot steel goes from red to nearly white). The carbon in the steel essentially dissolves and coexists with the iron in a special state where the crystals have a face-centered cubic structure. By adding other trace metals to the alloy such as nitrogen, nickel and manganese, the austenite can be maintained as the metal cools to create a steel that has high strength properties at elevated temperatures. Nitrogen also combines with carbon to form "carbonitrides" that add strength and hardness. Chromium is added to increase corrosion resistance. The end product is an alloy that may not be as hard at room temperature as a martensitic steel, but is much stronger at the high temperatures at which exhaust valves commonly operate. Though austenitic stainless steel can handle high temperatures very well, the steel is softer than martensitic steel at lower temperatures and cannot be hardened by heat treating. To improve wear, a hardened wafer tip may be welded to the tip of the valve stem. Or, on some applications an austenitic stainless valve head may be welded to a martensitic stem to create a two-piece valve that has a long wearing stem and heat resistant head. The only disadvantage with a two-piece valve is that it doesn't cool as well as a one-piece valve. The junction where the two different steels are welded together forms a barrier that slows heat transfer up the stem.
21-2N alloy has been around since the 1950s and is an austenitic stainless steel with 21 percent chromium and 2 percent nickel. It holds up well in stock exhaust valve applications and costs less than 21-4N because it contains less nickel. 21-4N is also an austenitic stainless steel with the same chromium content but contains almost twice as much nickel (3.75 percent), making it a more expensive alloy. 21-4N is usually considered to be the premium material for performance exhaust valves. 21-4N steel also
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meets the "EV8" Society of Automotive Engineers (SAE) specification for exhaust valves.
SAE classifies valve alloys with a code system: "NV" is the prefix code for a low-alloy intake valve, "HNV" is a high alloy intake valve material, "EV" is an austenitic exhaust valve alloy, and "HEV" is a high-strength exhaust valve alloy. Unfortunately, you can't always tell what kind of alloy a valve is made from because different valve suppliers use different alloys as well as their their own proprietary names for their valve materials. Thus one manufacturer may call their intake valve material a "422 stainless alloy" while another refers to it as an "NK-842 stainless intake material." Without a thorough metallurgical analysis, you can't really compare one manufacturer's valve material to another's. But do you really need such a comparison? As long as the alloy does what it is supposed to do, it doesn't matter what they call it. The bottom line here is that intake valves and exhaust valves both require different types of alloys. The same alloy can be used for both intake and exhaust valves (say 21-2N or 21-4N, for example), but the best results are usually obtained when different alloys are selected for the intake and exhaust valves. Why? Because an exhaust alloy that has good high temperature strength and corrosion resistance really isn't needed on the intake side, and it may not have the hardness and wear resistance of an intake alloy at lower temperatures. Even so, some companies sell the same alloy for both intake and exhaust valves while others offer different alloys for intake and exhaust valves. Intake valves run cooler and are washed with fuel vapors which tend to rinse away lubrication on the valve stem. So for intake valves, wear resistance may be more important than high temperature strength or corrosion resistance if the engine will be involved in any kind of endurance racing. Exhaust valves, on the other hand, run much hotter than intake valves and must withstand the corrosive effects of hot exhaust gases and the weakening effects of high temperatures. Consequently, a premium valve material is an absolute must on the exhaust side - especially in turbocharged and supercharged engines and those that inject nitrous oxide to boost power. As combustion temperatures go up, valve alloys that work fine in a stock engine may not have the strength, wear or corrosion resistance to hold up in a performance application. If you want the valves to last, especially in a highly modified racing engine, upgrading to better valve alloys will be a must. The best advice is to follow the valve alloy recommendations of your valve supplier, and to rely on their expertise when it comes to picking the best valve material for a performance application. If a stock valve alloy is holding up well enough in a performance application, there's no need to upgrade. But if an engine is experiencing valve burning or premature valve failure, then an upgrade to a better material may be needed to solve the problem. xi
Selection of material on the basis of properties CRITERIA OF INLET VALVE
High wear resistance Corrosion resistance High strength Availability of material supplied Overall cost (material and manufacturing costs )
CRITERIA OF EXHAUST VALVE
Resistance to high-temperature corrosion [ 700°C ] Hot strength (endurance strength at high temperature )[ ~500MPa ] Hot hardness [ strength at ~700°C ] Resistance to oxidation Resistance to seizing and galling Availability of material supplied
Overall cost (material and manufacturing costs )
ABOUT MATERIAL COMPOSTION
Steel
Melting Point( > 400°C ) Tensile Strength (~500MPa) Cost of material relative to relative to
Nickel
√
√
√
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moderate Nickel
High (Moderate)` steel
From the table shown above, the material that fulfill our criteria is only STEEL. Therefore we eliminate nickel and so only left the steel group. xii
From thestrength-temperatureashby chart,the suitable steel hadbeen chosen is STAINLESS STEEL. Stainless Steels are iron-base alloys containing Chromium. Stainless steels usually contain less than 30% Cr and more than 50% Fe. They attain their stainless characteristics because of the formation of an invisible and adherent chromium-rich oxide surface film. This oxide establishes on the surface and heals itself in the presence of oxygen.
Stainless steels are commonly divided into five groups:
Martensitic stainless steels Ferritic stainless steels Austenitic stainless steels Duplex (ferritic-austenitic) stainless steels
Precipitation-hardening stainless steels
.
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Finally, the specific type of material that we choose is Austenitic stainless steels Martensitic stainless steels
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CLASSIFICATION OF VALVES
ENGINE VALVES
INLET VALVE
INLET VALVE
EXHUST VALVE
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Inlet Valve is that valve through which fuel or a mixture whose pressure in increased by reducing its volume in intaked into the cylinder.
EXHUST VALVE
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Exhaust valve is precision engine components used to open to permit the burned gases to exhaust from cylinders. Therefore exhaust valve are exposed to serve thermal loads and chemical corrosion.Exhaust valve are opens and closes as many as 2000 times per mile
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PROSSES OPERATION SEQUENCE RAW MATERIAL
FRICTION WELDING &DFLASH
UPSEETING
FORGING
HEAT TREATMENT
SHOT BLASTING
STRIGHTENING
STEAM END CUT
STELLITE GROOVING
SEAT SETELLITING
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TIP DRILLING
TIP SETELLITING
END GRINDING
ULTRASONIC INSPECTION
POST OD TRAINING
MACHINE SHOP
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BRIEF INTRODUCTION ABOUT EACH PROCESS RAW MATERIAL - A Raw material or feedstock is the basic material from which a product is manufactured or made, frequently used with an extended meaning. First, the raw material ( Stainless Steel rod ) is undergoing hot directextrusion to get the required diameter.
FRICTION WELDING
- Friction welding is a process of joining head diameter of
the engine valve with the straight rod use fully automatic machine. It is needed only for the bimetallic valve. Friction welding technology is a completely mechanical solid-phase process in which heat generated by friction is used to create high-integrity joint between similar or dissimilar metals, and even thermoplastics.
Advantages : 1. High production volume 2. Low cost per pound 3. Many types of raw material
Disadvantages : 1. Limited complexity of parts 2.Uniform cross-section shape only
UPSETTING - After the raw material is undergoing extrusion, the next step is upsetting process. This process purpose is to give initial shape that will be forwarded to next step that is forging process. Steps : 1.The steel is heated by electrical resistance between two contacts. 2.As the steel reaches its plastic temperature more material if forced through the contacts by a hydraulic ram until enough volume is "upset" to make the pre-form. 3.Then, the pre-form is then passed immediately to the forge.
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FORGING
- Forging is the process by which metal is heated and is shaped by plastic
deformation by suitably applying compressive force. Usually the compressive force is in the form of hammer blows using a power hammer or a press. After upsetting process the upsetted part will go through forging process immediately. Forging is the term for shaping metal by using localized compressive forces. The forging process of producing exhaust valve is Hot Forging on Friction Screw and High Speed Precision Forging Presses, where the press capacity is 5kgs.
Forging
Forging refines the grain structure and improves physical properties of the metal. With proper design, the grain flow can be oriented in the direction of principal stresses encountered in actual use. Grain flow is the direction of the pattern that the crystals take during plastic deformation. Physical properties (such as strength, ductility and toughness) are much better in a forging than in the base metal, which has, crystals randomly oriented. All of the following forging processes can be performed at various temperatures, however they are generally classified by whether the metal temperature is above or below the recrystallization temperature. If the temperature is above the material's recrystallization temperature it is deemed hot forging; if the temperature is 3 below the material's recrystallization temperature but above ⁄ 10ths of the recrystallization 3 temperature (on an absolute scale) it is deemed warm forging; if below ⁄ 10ths of the recrystallization temperature (usually room temperature) then it is deemed cold forging. xx
The main advantage of hot forging is that as the metal is deformed work hardening effects are negated by the recrystallization process. Cold forging typically results in work hardening of the piece. The most common type of forging equipment is the hammer and anvil. Principles behind the hammer and anvil are still used today in drop-hammer equipment. The principle behind the machine is very simple — raise the hammer and then drop it or propel it into the workpiece, which rests on the anvil. The main variations between drop-hammers are in the way the hammer is powered; the most common being air and steam hammers. Drop-hammers usually operate in a vertical position. The main reason for this is excess energy (energy that isn't used to deform the workpiece) that isn't released as heat or sound needs to be transmitted to the foundation. Moreover, a large machine base is needed to absorb the impacts. To overcome some of the shortcomings of the drop-hammer, the counterblow machine or impactor is used. In a counterblow machine both the hammer and anvil move and the workpiece is held between them. Here excess energy becomes recoil. This allows the machine to work horizontally and consist of a smaller base. Other advantages include less noise, heat and vibration. It also produces a distinctly different flow pattern. Both of these machines can be used for open die or closed die forging. A forging press, often just called a press, is used for press forging. There are two main types: mechanical and hydraulic presses. Mechanical presses function by using cams, cranks and/or toggles to produce a preset (a predetermined force at a certain location in the stroke) and reproducible stroke. Due to the nature of this type of system, different forces are available at different stroke positions. Mechanical presses are faster than their hydraulic counterparts (up to 50 strokes per minute). Their capacities range from 3 to 160 MN (300 to 18,000 short tons-force). Hydraulic presses use fluid pressure and a piston to generate force. The advantages of a hydraulic press over a mechanical press are its flexibility and greater capacity. The disadvantages include a slower, larger, and costlier machine to operate.
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Forging prosses
Advantages : 1..Flexibility of design process 2.Versatility of the forging itself .
Disadvantages : 1.The skill involved is not easily acquired 2.Tooling needed represents a considerable amount of time and money invested.
HEAT TREAMENT
- The next step after the exhaust valve had been forged is heat treatment.
Heat treatment of these grades consists of solution treatment so as to get a single phase structure.heat treatment prosses of engine valves are completed into three steps.
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HEAT TREAMENT
QUENCHING
QUENCHING
WASHING
TEMPERING
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Quenching is the rapid cooling of a workpiece to obtain certain material properties. It prevents low-temperature processes, such as phase transformations, from occurring by only providing a narrow window of time in which the reaction is both thermodynamically favorable and kinetically accessible. For instance, it can reduce crystallinity and thereby increase toughness of Stainless Steel rod. Quenching metals is a progression; the first step is soaking the metal, i.e. heating it to the required temperature. Soaking can be done by air (air furnace), or a bath. The soaking time in air furnaces should be 1 to 2 minutes for each millimeter of cross-section. For a bath the time can range a little higher. The recommended time allotment in salt or lead baths is 0 to 6 minutes. Uneven heating or overheating should be avoided at all cost. Most materials are heated from anywhere to 815 to 900 °C (1,500 to 1,650 °F).
WASHING
– After quenching washing is the next step.In washing quenched product
washed by water.then it goes for tempering.
TEMPERING
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Untempered martensitic steel, while very hard, is too brittle to be useful for most applications. A method for alleviating this problem is called tempering Heating a quench hardened or normalized ferrous alloy to a temperature below the transformation range to produce desired changes in properties. The object of tempering or drawing is to reduce the brittleness in hardened steel and to remove the internal strains xxiii
caused by the sudden cooling in the quenching bath. The tempering process consists in heating the steel by various means to a certain temperature and then cooling it. When steel is in a fully hardened condition, its structure consists largely of martensite. On reheating to a temperature of from about 300 to 750°F., a softer and tougher structure known as troostite is formed. If the steel is reheated to a temperature of from 750 to 1290°F, a structure known as a sorbite is formed, which has somewhat less strength than troostite, but much greater ductility. Tempering consists of heating a steel below the lower critical te mperature, (often from 400 to 1105 ˚F or 205 to 595 ˚C, depending on the desired results), to impart some toughness. Higher tempering temperatures, (may be up to 1,300 ˚F or 700 ˚C, depending on the alloy and application), are sometimes used to impart further ductility, although some yield strength is lost. Tempering may also be performed on normalized steels. Other methods of tempering consist of quenching to a specific temperature, which is above the martensite start temperature, and then holding it there until pure bainite can form or internal stresses can be relieved. These include austempering and martempering.
SHOT BLASTING - Shot Blasting is a surface treatment process using high velocity steel abrasive. Shot blasting is method through which it is possible to obtain excellent cleaning and surface preparation for secondary finishing operations or abrasive blasting is the operation of cleaning or preparing a surface by forcibly propelling a stream of abrasive material against it. Usually explained as the use of a material against another material to make it smoother, remove surface contaminants or to roughen a surface. It is also the appropriate term for what is known as glass bead blasting or shot blasting. Shot blasting is commonly used for: • The cleaning of iron, steel, non-cast parts, forgings, etc. • Mechanical cleaning of sheets, rods, coils, wire, e tc. • Shot peening to alter mechanical properties (increasing resistance to fatigue for springs, gears, etc.) • Preparing surfaces to be painted, coated, etc. In general shot blasting concentrates abrasive particles at high speed (65-110 m/second) in a controlled manner at the material thereby removing surface contaminates due to the abrasive impact.
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Abrasive delivery method There are two ways of accelerating the steel shot:
a)
By compressed air
This system is suitable for lower production applications where maximum flexibility is needed. These systems are very flexible in that the shot can be delivered horizontally through a rubber hose and nozzle assembly. This enables uses in finishing operations of steel frames andweldments thereby replacing hand tools. Because of this, an air blasting machine for a production line is expensive compared to the centrifugal wheel blasting machine. For example to deliver shot at a rate of 1100 kg per minute a 1650 Hp compressor and 33 workers are needed using 10 mm diameter nozzles delivering 6.5 kg/cm2. On the other hand the same task using centrifugal wheel turbines only requires a total of 100 Hp distributed to between one or a multitude of turbines housed in the same machine. Only one or two operators are needed for such a shotblasting machine.
Shot blasting by compressed air b)
By centrifugal turbine
Centrifugal wheel blasting is the more common blast cleaning technique as well as the most economical and environmentally friendly method. The turbine delivers abrasive shot by centrifugal force in a specific and controlled direction, speed and quantity. Function of the turbine is similar to that of a fan or centrifugal pump. Shot blasting machines may use one or a multitude of turbines positioned in such a way that the abrasive blast pattern covers the entire surface of the material to be shot cleaned. The shape and size of the parts determine thnumber of turbines. used in a machine. Power of xxv
the turbine motor is based on degree of cleaning needed and throughout speed of the material.
Shot blasting by centrifugal turbine . .
STRIGHTENING
- During the heat treatment process temperature of the valve
become very high. At this high temperature there are some bending occure in engine valve. So in this process valve is passes through between two die at high pressure.by which bending from valve is reduce at considerable level.
STEAM END CUT
- After strighting prosses the length of stem of the engine
valve is increases due to increases in the straightness of the stem.so the undesirable length of the stem is cut by the cutter.the length of the stem is taken as fixed standard which are followed by the company.
STELLITE GROOVING - This prosses is used to increase the strength of the stet of the engine valve.In this prosses a groove is made at the valve seat in which filler material is filled.
SEAT SETELLITING
-
The follow up process after the heat treatment is satellite welding process.Stellite is a special alloys that welded onto the seat.Purpose is to improve the corrosion and high temperature wear resistance, mainly in valves; a cord of special material is placed onto the valve seat. xxvi
Advantages : 1.High residual stresses are relieved 2. Hardness improved 3. Overlaid with corrosion and wear resistant material (stellite) for long service life.
TIP DRILLING
– Some time there in need to increase the strength of the tip of the
engine valve.so tip drilling is the first step to increase the strength of the engine valve.so by drilling space in the tip of engine valve is made to fill the filler matel.
TIP SETELLITING
- The next process is tip hardening process. The machine used
is fully automatic machine, which is Valve Stem-End Induction Hardening machine that can provide perfect quality of hardening. The purpose of this process is to increase the wear resistant of the tip since this part is continuously pounded by camshaft during the operation of exhaust valve.
Advantages : 1.Increasing the cyclic crack resistance of structural parts.
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END GRINDING
– After tip setelliting there is some unwanted material remaining
at the tip of the engine valve.so to remove the unwanted material grinding of the tip of the engine valve is necessary.so in this prosses grinding of the tip is done.
ULTRASONIC INSPECTION
– During the manufacturing process there is
some chance of forming of blow hole or crack inside the engine valve.so it is necessary to found these blow hole or crack inside the engine valve.so ultrasonic inspection is used for this purpose. In ultrasonic testing (UT), very short ultrasonic pulse-waves with center frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz are launched into materials to detect internal flaws or to characterize materials. The technique is also commonly used to determine the thickness of the test object, for example, to monitor pipework corrosion. Ultrasonic testing is often performed on steel and other metals and alloys, though it can also be used on concrete, wood and composites, albeit with less resolution. It is a form of non-destructive testing used in many industries including aerospace, automotive and other transportation sectors.
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Ultrasonic inspection
Advantages 1. 2. 3. 4.
High penetrating power, which allows the detection of flaws deep in the part. High sensitivity, permitting the detection of extremely small flaws. Only one surface need be accessible. Greater accuracy than other nondestructive methods in determining the depth of internal flaws and the thickness of parts with parallel surfaces. 5. Some capability of estimating the size, orientation, shape and nature of defects. 6. Nonhazardous to operations or to nearby personnel and has no effect on equipment and materials in the vicinity. 7. Capable of portable or highly automated operation.
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