Group 1: Lucky Buğra

Crankshaft

Güçlü Yardımcı Fatih Cemal ÜlgenAli Buğra Basan &Güncel Kırlangıç

What is a Crankshaft?

• The engine part that turns the linear motion of the piston into rotational motion.

• It is essential for every type of Internal Combustion Engine.

• Varient sizes of crankshafts are avalible in cars, helicopters, cruise ships.

Brief History of Crankshaft

• Firstly used in a Roman sawmill in 3rd century.

• Used to turn circular motion into linear motion.

• In 15th century, they are used in paddle-wheel boats.

• Also used in the studies of Leonardo da Vinci.

• Gained importance after industrial revolution.

• Used in every internal combustion engine today.

Requirements• It has to endure high amount of

torsional and bending stresses.

• It should have high resilience and fatigue resistence to prevent deformation.

• It needs to have an endurance limit since it has to endure many cycles.

• It should also have a low density so that the vehicle will have a better performance.

• It should have a high wear resistence and surface hardness to prevent surface cracks.

Material Selection

Currently Used Materials

• The main materials used in crankshaft manufacturing are steel alloys.

• The plain carbon alloys such as AISI 1010, 1045, and 1053 are widely used in low-power engine crankshafts.

• For high-power engines, trucks or racing cars, AISI 5140, 4130, and 4340 are used.

• Arrow Precision, uses 722M24 or other commercially available aerospace grade steels.

• The French manufacturer Aubert&Duval uses 32-CrMoV-13.

Properties of currently used materials

Overall;

•Stiffness

•Torsional and Bending Strength

•Fatigue strength

•Hardness

•Resilience are the main properties that affect the crankshaft life and/or quality.

AISI 1010 CARBON STEEL

Element Content (%)

Iron, Fe 99.18-99.62 %

Manganese, Mn 0.30-0.60 %

Sulfur, S ≤0.050 %

Phosphorous, P ≤0.040 %

Carbon, C 0.080-0.13 %

Properties Metric

Tensile strength 365 MPa

Yield strength (depending on temper) 305 MPa

Elastic modulus 190-210 Gpa

Hardness, Rockwell B (converted from Brinell hardness)

60

AISI 4340Element Content (%)

Iron, Fe 95.195 - 96.33

Nickel, Ni 1.65 - 2.00

Chromium, Cr 0.700 - 0.900

Manganese, Mn 0.600 - 0.800

Carbon, C 0.370 - 0.430

Molybdenum, Mo 0.200 - 0.300

Silicon, Si 0.150 - 0.300

Sulfur, S  0.0400

Phosphorous, P  0.0350

Properties Metric

Tensile strength 745 MPa

Yield strength 470 MPa

Elastic modulus 190-210 GPa

Hardness, Rockwell B (converted from Brinell hardness)

95

Problems encountered in current materials

• Crack formation, bending of the crankshaft, and surface damage due to friction.

• There are many causes but most important ones are;- Loss of effective lubrication

- Faulty crankshaft damper or detuner

- Bearing misalignment

- Overloading of engine

- Failure due to fatigue

New Material Options

• Carbon Fiber Reinforced Polymer has perfect properties although complex shapes cannot be created.

• CentrAL (Central Reinforced Aluminum) is also a good choice although it has to be manufactured with powder metallurgy which is not a feasible method for crankshaft production.

• SiCp Particulated Aluminum Alloy is the solution since it is lightweight, has better properties than AISI 4340, and can be produced by casting.

Our Solution:

SiCp Particulated Aluminum Alloy

+ =

SiCp Particulated Aluminum Alloy

SiCp Particulated Aluminum Alloy

Matrix

AI-UTN15 with SiCp Particles

• Very high yield strength (Expected value is around 1000 Mpa)

• Much lighter then High Strength Steels (density of AISI 4340 is 7.85 g/cm3 our material is 2.88 g/cm3 )

• High fatigue strength (Expected fatigue strength is higher then AISI 4340)

• High resilience

Manufacturing Process

Currently Used Processes• Casting: Green mold casting and shell mold casting. Lower strength product, cheap process.

• Forging: Machining required after forging. Cheaper in mass production.

• Machining: Directly machined to final shape from billet. Best dimensional accuracy and design flexibility. Low production rate and costly.

• Heat treatments and surface treatments are available for all the manufacturing processes.

• Powder Metallurgy: Problems due to part shape. Part can’t be divided into male and female molds.

• Die Casting: High tooling cost and complicates heat treatment.

• Carbon Fiber Molding: Molding problems due to crankshaft shape.

Alternative Processes

Our Manufacturing Process• Atomization: Silicon Carbide particles are manufactured by atomization. High pressure air is sprayed to liquid SiC which is poured through

a small orifice. SiC particle size is controlled by the air pressure and filter.

• Mixing: SiC particles are mixed to the molten aluminum and the mixture

is stirred for a homogenous structure. Since the melting T of SiC is much higher than aluminum, it does not change phase.

• Casting:Aluminum has to be molten to mix with SiC particles. Since the

aluminum has molten, casting is the best option for manufacturing.

Shell mold casting is preferred for better surface finish and dimensional tolerances than sand casting.

• Heat Treatement:After the part is removed from the mold, T7 heat treatement is

applied. Stabilization of the material will prevent long term strength drops.

• Surface Treatment:Fillet rolling rounds up and smoothens the pin and main fillets.

Compressive residual stresses improve fatigue strength.

• Anodizing:Aluminum hard coat anodizing provides a smooth, hard,

corrosion resistant and wear resistant surface. In this process, part is dipped into acid bath and an uniform aluminum oxide layer is formed on the surface. Thickness depends on the waiting time.

QUALITY CONTROL AND TESTING

Main Topics• Chemical analysis for the material

– X-ray fluorescence (XRF)– X-ray photoelectron spectroscopy (XPS)– Scanning electron microscopy (SEM)

• Quality control of the part with mechanical testing– Fatigue test– Bending test

• Forming inspection– Dimension control– Heat treatment control

• Hardness test• Conductivity test

• Non-destructive testing– Liquid penetrant– Radiography

Chemical Analysis

• X-ray fluorescence (XRF): It is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays.

• It will be used in the examination of composition and impurity percentage.

Chemical Analysis

• X-ray photoelectron spectroscopy (XPS): It is a surface-sensitive quantitative spectroscopic technique that measures the elemental composition at the parts per thousand range, empirical formula, chemical state and electronic state of the elements that exist within a material.

• Since we can measure the uniformity of a chemical composition, with this method, we will be able to see the homogeneity of the matrix - particle mixture.

Chemical Analysis

Scanning electron microscope (SEM): •It is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. •Thermionic emission with lanthanum hexaboride.

Chemical Analysis

• Images will be used for measuring the particle size.

• Volume percentage of silicon carbide by Clemex Image Analyzing Program.

Quality Control with Mechanical Testing

Fatigue Test•Fatigue is the weakening of a material caused by cyclic loading.•If our part's fatigue strength is resistant enough for an automotive engine to withstand the cyclic loads.

Quality Control with Mechanical Testing

Bending Test•Crankshaft undergoes a lot of bending stress caused by the connecting rod.•This test will be carried out to see the part's bending strength, and if it is high enough for a crankshaft.

Forming Inspection

Dimension Control•Comparison between the part and its 2D/3D model.•Can be measured manually with tools.•Dimensional stability by placing onto exact scaled blueprints.

Forming Inspection

Heat Treatment Control•Microstructural changes•Hardness and conductivity tests•Tabulated hardness and conductivity ranges

Forming Inspection

Conductivity Test• Conductivity value relative to the copper’s

conductivity• Default value is 8.2, pure copper’s conductivity is

100.• Calibration is important.

Forming InspectionHardness Test

• Hardness is the resistance to permanent indentation.

• Rockwell Hardness Test will be conducted.

• Diamond cone for hard materials, steel ball for soft materials.

Non-Destructive TestingLiquid Penetrant•Inspection of surface cracks•The part is dipped into liquid penetrant, cleaned, and inspected under blacklight.

Non-Destructive Testing

Radiography•To determine the interior cracks and porosities•Alpha and/or gamma rays

Summary

• SiC particulated aluminum alloy is the new material for crankshaft.

• Particle manufacturing method is atomization.• The part’s manufacturing process is casting.• Heat treatment, fillet rounding, and anodizing

are after processes.• Chemical analysis, mechanical tests, forming

inspections, and non-destructive testing methods are conducted for quality control.

THANK YOU FOR LISTENING