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Given paper is about Evolution of Engineering materials used for manufacturing automobile parts i.e. new materials

Home, - CRANKSHAFT RESEARCH PAPER


INTRODUCTION
The introduction of new materials into automobile manufacturing has often been dictated by how fast such materials can be processed in the production line .Right from the first cars until the present, steel has been the preferred option for structural components requiring high strengths.
This term paper explains the properties and characteristics that a suitable material should have to be accepted in automotive production. In also gives a detailed review of the history of development of the materials in automotive from the most traditional to the most recent ones. In the category of the metallic materials like steel, aluminium and magnesium and the most recent alloys of these used in the automotive are explained. Some of the properties, manufacturing and joining processes for these metals are described. The advantages and problems of using each of these materials are also discussed. The potential application of these materials in different parts of a vehicle is identified.
But with the need to produce lighter cars being driven by the C02 emission regulations imposed for new car builds ,the term paper will also cover on the technical ,economical ,legal ,sustainability and social hurdles that could hinder some of the candidate engineering materials. 
CONTENT
Materials that are applied in manufacturing in engineering are very broad and are also used in extensive applications . And for the topic under car materials some of the requirements of the materials in automotive design include;
Lightweight
As there is a high emphasis on greenhouse gas reductions, reduction of emission and improving fuel efficiency this criterion is most important one for an automotive company. Lightweight materials can improve fuel efficiency more than other factors. Experiments reveal that 10 percent of weight reduction can lead to 6 to 8 percent improvement in fuel usage. Weight reduction can be obtained by three ways:
• Replacing materials of high specific weight with lower density materials without reducing rigidity and durability. For example replacement of steel with aluminium, magnesium, composites and foams.
• Optimizing the design of load-carrying elements and exterior attachments so as to reduce their weight without any loss in rigidity or functionality.
• Optimizing the production process, such as reducing spot welding and replacing new joining techniques.
But the single main obstacle in application of lightweight materials is their high cost. Yet the weight reduction is still the most cost-effective means to reduce fuel consumption.

Economic effectiveness
One of the most important consumer driven factors in automotive industry is the cost, that determines whether any new material has an opportunity to be selected for a vehicle component. Cost includes three components: actual cost of raw materials, manufacturing value added, and the cost to design and test the product.
Aluminum and magnesium alloys are certainly more costly than the currently used steel and cast irons. Since cost may be higher, decisions to select light metals must be justified on the basis of improved functionality. Meanwhile the high cost is one of the major obstacles in use of the composite materials.
Safety
The ability to absorb impact energy and be survivable for the passengers is called "crashworthiness" of the structure in vehicle. At first two concepts in automotive industry should be considered: crashworthiness and penetration resistance. In the more accurate definition of crashworthiness, it is the potential of absorption of energy through controlled failure modes and mechanisms. However, penetration resistance is concerned with the total absorption without allowing projectile or fragment penetration.
Recycling
The most important concerns in industeries such as automotive, are ‘protection of resources', ‘reduction of CO2 emissions', and ‘recycling'
CRANKSHAFT
Description of a crankshaft.
Crankshaft is a shaft which is connected perpendicularly to piston through connecting rod .At the one end of crankshaft, the flywheel is connected. Flywheel is a energy reservoir, that receives energy from the piston during power stroke and it gives back the same energy to the piston during remaining strokes due to the moment of inertia. On the other end, the shaft is connected to camshaft through belt drive which helps for opening and closing the inlet and exhaust valves.
Crankshaft is a part of the engine that helps you convert the linear motion of the Piston into rotary motion that can be delivered to the gearbox/wheels. Without the crankshaft you can't transfer the reciprocating motion of pistons to the drive shaft. It also holds The flywheel which is like an energy reservoir that helps maintain the constant reciprocating motion of the Piston without any mis-alignment and mis-firing. It's also the connecting link between the engine and the gearbox/drive shaft. Power is delivered from the crankshaft to the wheels/geabox.
Functional requirements of crankshafts.
The steel alloys are used in high strength crankshafts for what each designer perceives as the most desirable combination of properties.The alloying elements typically used in these carbon steels are magnesium, chromium , molybdenum, nickel , cobalt and vanadium must been carefully designed to produced specific requirements in mechanical, chemical and physical properties stated below.
Medium carbon steel are commonly used and are highly favoured in manufacturing of crank shaft since it provides all basic functional requirements for working of a crankshaft to its best performance. Therefore for maximum power output by the crankshaft the following material requirements must be attained :
• Hardenability : have high hardness.
• Ultimate tensile strength of 620 Mpa, yield strength of 415 Mpa ,and high endurance limit (fatigue strength)
• Core hardness
• Material should be ductile: Ductility
• Impact resistant
• Corrosion resistant
• Temper-embrittlement resistant.(Thermal expansion co-efficient 0f 11.3 m/m0c)
1040 Carbon steel is regularly the chosen medium carbon steel.
History of development and evolution of material used to make crankshafts.
Until around 1960 ,carbon steels of 450 M pa class had been used for the solid type crankshaft. Subsequently, low alloy steels began to be used and have gradually increase in usage. Currently more than 50 % of crankshafts use low-alloy steels (>800 Mpa). A noteworthy trend is recent application of super high strength steel of 950 Mpa class.
Advances in steel making technology are essential for reducing impurities for crankshaft. The removal phosphorous and sulphur are especially important along with degassing .Until around 1998 tap degassing process (TD Process) until around 1988. Subsequently the ladle furnace process( LF Process)
Older crankshaft technology involved heat-treating to a higher core hardness and shotpeening the fillet radii for fatigue improvement.
Manufacturing processes of crankshafts
There are two main ways of producing crankshafts :
Forging : A billet is heated to an approximate forging temperature usually between 1065-1230.The heated billet is then pressed into the required shape by a pair of dies squeezing the material under very high pressure. More sets of dies are required when more intricate shapes are attempted.
Machining: Motorsport engines require more defined and cmplex crankshafts therefore they are machined from a billet to produce a more accurate shape. The use of Cnc and 3D CAD programs allow rapid alterations to be made to tweek designs to create an optimal working engine. CNC also makes producing these components very cost effective.
Regarding the steel alloys typically used in high-grade crankshafts, the desired ultimate (and hence yield and fatigue) strength of the material is produced by a series of processes, known in aggregate as ‘heat treatment'.

The typical heat-treating process for carbon-steel alloys is first to transform the structure of the rough-machined part into the face-centered-cubic austenite crystalline structure (‘austenitize') by heating the part in an oven until the temperature throughout the part stabilizes in the neighbourhood of 950°c to 1356°c (depending on the specific material). Next, the part is removed from the heating oven and rapidly cooled ("quenched") to extract heat from the part at a rate sufficient to transform a large percentage of the austenitic structure into fine-grained martensite. The desired martensitic post-quench crystalline structure of the steel is the high-strength, high-hardness, form of the iron-carbon solution. The rate of cooling required to achieve maximum transformation varies with the hardenability of the material, determined by the combination of alloying elements.


CAR FRAME.
Description of a car frame..
A vehicle frame also known as its chassis , is the main supporting structure os a motor vehicle to which all other components are attached , comparable to the skeleton of an organism

Functional requirements of car frame
Minimize momentum by cutting out excess materials
Bend ability ( ductility)-Car frames are designed so that there is less material at desired point of bending hence bending can be done without damaging parts that should not be bent
Easy to manufacture and assemble by minimizing number of parts.

History of development and evolution of material used to make car frames.
The structures were made of a wooden frame with wooden body panels mounted on it.An introduction of steel and aluminum sheets(1900) enabled the designers to create shapes with more freedom.
In 1922 the Lancia Lambda was a revolution in the evolution of chassis design. Inspired by shipbuilding the design emphasized on All steel body monocoque structure Dogde brothers (1914)
Properties of materials used to make car frames
Some of the properties use in the construction of car frames with their respective properties include :
Aluminium
Use of aluminium can potentially reduce the weight of the vehicle body. Its low density and high specific energy absorption performance and good specific strength are its most important properties.
Aluminium is also resistance to corrosion. But according to its low modulus of elasticity, it cannot substitute steel parts and therefore those parts need to be re-engineered to achieve the same mechanical strength, but still aluminium offers weight reduction.
Magnesium
Magnesium is another light metal that is becoming increasingly common in automotive engineering. It is 33% lighter than aluminium and 75% lighter than steel/cast iron components. Magnesium components have many mechanical/physical property disadvantage that require unique design for application to automotive products. Although its tensile yield strength is about the same, magnesium has lower ultimate tensile strength fatigue strength, and creep strength compared to Aluminium. The modulus and hardness of magnesium alloys is lower than aluminium and the thermal expansion coefficient is greater.
Magnesium alloys have distinct advantages over aluminium that include better manufacturability, longer die life and faster solidification. Also magnesium components have higher machinability.
Advanced composite materials
Fibre reinforced composites offer a wide range of advantages to the automotive industry. It has the potential for saving weight offered by their low density. Component designs can be such that the fibres lie in the direction of the principal stresses, and amount of fibre used is sufficient to withstand the stress, thus optimizing materials usage.
Carbon-fibre epoxy composite
Most recently, the most of the racing car companies much more rely on composites form whether it would be plastic composites, Kevlar and most importantly carbon-fibre epoxy composition. It is because the composite structures is the high strength/low weight ratio. The most common materials used for racing cars are carbon (graphite), Kevlar and glass fibres. Epoxy composites have been the first choice in Formula 1 car industeries and other race cars.
Glass-fibre composites
Glass fibre is being used mostly for the sports car which includes Formula 1 cars. It is lighter than steel and aluminium, easy to be shaped and rust-proof. And more important factor is that it is cheap to be produced in small quantity

The values and properties of different materials used in the design and manufacturing of car frames.
FENDERS
Description of a fenders
It is a part of an automobile, motorcycle or other vehicle body that frames a wheel well.It's primary purpose is to prevent sand , mud ,rocks, liquids and other road spray from being thrown into the air by the rotating tire.
Functional requirements of . fenders
Should have the capability to absorb impact and impact resistant
Corrosion resistant.
Manufacturing of fenders.
The following are manufacturing procedure that are used in processing fenders;
Method 1 : It includes stamping a right fender and its complementary left fender from a unitary sheet metal blank at one and the same time and forming the inner edge portion of each complete fender from the intermediate portion of the blank.
Method 2 : This is method of manufacturing automobile fenders which includes holding a. sheet metal blank along opposite edges, stamping the blank so held to form a right fender and its complementary left fender at one and the same operation and forming the outer edge portion of one fender from that portion of the blank adjacent to one held edge thereof and forming the outer edge portion of the other fender from that portion of the blank adjacent to the other held edge thereof and forming the inner edge portion of each fender from the intermediate portion of the blank.
Method 3 : Manufacturing an automobile front fender having a crown, an outer edge portion bent downwardly substantially at a right angle to the crown and an inner edge portion sloping gradually downwardly away from the crown at a slight angle which comprises holding a unitary sheet metal blank along opposite edges, stamping the blank so held to form therein at one operation a right fender and its complementary left fender, said stamping operation including subjecting that portion of the blank adjacent to each of said held edges to substantially the same amount of distortion and to a substantially greater distortion than the intermediate portion of the blank and forming there from the outer edge portions of the two fenders, and subjecting the intermediate portion of the blank to substantially less distortion and forming there from the inner edge portions of the two fenders, separating the two fenders stamped in the blank and trimming each to size.
Method 4 :This is a method of shaping an automobile fender blank as an intermediate step in the manufacture of automobile fenders comprising stamping a unitary sheet metal blank to form with one and the same operation a right fender and its complementary left fender, and forming the outer longitudinal edge portion of each fender from an outer edge portion of the blank and forming the inner edge portion of each fender from the intermediate portion of the blank.
Method 5 : In this method of manufacturing a pair of automobile front fenders comprising holding a unitary sheet metal blank along opposite edges, stamping the blank so held to form at one and the same operation a pair of complementary front fenders. said stamping operation including subjecting that portion of the blank adjacent to each held edge to considerable distortion and forming there from and at substantially a right angle thereto the outer edge portion of one of the fenders and subjecting the intermediate portion of the blank to very considerably less distortion and forming there from and at a relatively slight angle thereto the inner edge portion of each fenders


Major property requirements of materials used in fender manufacturing.
Though metals like steel and aluminium are applied in manufacture of fenders, the major materials used are modern plastics which have the following properties.


History of development and evolution of material used to make fenders
The cars from a few decades back used steel and aluminium to provide cushioning and protection allowing the fender to absorb impact and remain relatively undamaged.But the recent development in polmers and polymerization has seen modern plastics covered Styrofoam and aluminium.
The majority of the modern plastic are made from thermoplastic olefins , polycarbonates, polyamides or blends with glass fibres.

Characteristics of materials used to make fenders.
High strength
High rigidity
Corrosion resistant
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STEERING KNUCKLE..
Description of a steering knuckle
A forged joint that usually includes the spindle and the steering arm , allowing the wheel to pivot , is known as a steering knuckle. It is a forged component that holds the assembly of the suspension, steering ,axle, brakes and wheel hub together.
It acts as the end joint which provides directional assistance as per the inputs of the steering wheel. The steering knuckle as the part of the wheel hub is finally bolted to the wheels.


Functional requirements of .steering knuckle.
The steering knuckle, being a part of the vehicle's suspension system, has alternatives of forging
and casting as its base manufacturing process. Since it is connected to the steering
parts and strut assembly from one side and the wheel hub assembly from the other, it
has complex restraint and constraint conditions and tolerates a combination of loads. In
addition, parameters such as internal defects, stress concentrations and gradients,
surface finish, and residual stresses can have considerable influence while designing
for fatigue. A common practice of fatigue design consists of a combination of analysis
and testing
Major property requirements of materials used in manufacturing the steering knuckle
A steering knuckle assembly that is made of a lightweight material, such as an aluminum-based material, but is strong enough to withstand various induced stresses like those caused during a press-fit installation of a wheel bearing assembly. In one embodiment, the steering knuckle assembly includes a steering knuckle component made of an aluminum-based material that is over-molded or cast around a reinforcing insert made of a stronger ferrous-based material. The reinforcing insert has an inner surface surrounding an opening that is designed to receive a wheel bearing assembly, where the inner surface can be machined before or after the over-molding or casting process.

Ductile irons and gray cast iron are the most widely used materials in manufacture of steering knuckles because of the following reasons
They are lightweight. They have more fatigue resistance which is a functional requirement. They have compressive strength that is comparable to low and medium carbon steels. They are resistant to high temperatures. Introduction of some alloys like chromium makes the corrosion resistant
Some of the numerical values of required physical properties have been shown in the table below.

History of development and evolution of material used to make steering knuckle
Cast iron has been always applied in the construction of steering knuckles since the automotive industry came to life in the early 1900's . As the development and discovery of new better alloys chips in the new era , possibilities of cast irons been thrown out increase with possibilities of aluminium alloys which are lighter , stronger and more resistant to chemical and extreme temperatures replacing them.
Characteristics of materials used to make the steering knuckle.
For processing and manufacturing of steering knuckle, Grey Cast iron is commonly used with the following properties usually taken into considerations :

General technical, economic ,legal, sustainability and hurdles that hinder application of candidate materials

Though steels and their alloys have proven to be the best materials for manufacturing application in automobile they face some challenges which are discussed below;
Raw materials trouble: With an extended fall in steel prices globally, steel making raw materials have been in a tough spot . The implosion in prices is attributed to large oversupply of raw materials and prolonged dullness in global economy that which resulted in over capacity in steel and losses .Few of the largest iron ore miners have cut down expansion plan and have shifted focus to low cost mining assets.
Low potential utilization: According to a research, the potential usage of steel and iron is quite low. It generally doesn't exceed 80%.
Huge demands : Even fter low per capita consumption rate of steel ,the demand for iron and steel is increasing everyday and huge chunks of iron and steel are to be imported in order to meet demands.
Some of the technical problem during processing of materials includes;
Distortion and induced residual stress are two of the biggest problems involved in heat-treating. Less severe quenching methods tend to reduce residual stresses and distortion. Some alloys (EN-30B and certain tool steels, for example) can reach full hardness by quenching in air. Other alloys having less hardened ability can be quenched in a bath of 400°F molten salt. Still others require quenching in polymer-based oil, and the least hardenable alloys need to be quenched in water. The shock of water-quenching is often severe enough to crack the part or induce severe residual stresses and distortions. As the harden ability of a material decreases, the hardness (thus strength) varies more drastically from the surface to the core of the material. High harden ability materials can reach much more homogeneous post-quench hardness
Economic hurdles.
The cost of aluminum and price stability is its biggest obstacle for its application..
CONCLUSION.
The choice of materials for a vehicle is the first and most important factor for automotive design. There is a variety of materials that can be used in the automotive body manufacturing, but the purpose of design is the main challenge here. The most important criteria that a material should meet are lightweight, economic effectiveness, safety, recyclability and life cycle considerations. Some of these criteria are the result of legislation and regulation and some are the requirements of the customers. The review of historical development of materials brings in a curiosity that the future will bring more eco friendly and stronger and durable materials that are cost effective and sustainable.

 

 

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