Rosioru Dragos 621 DACAD 2 PROJECT

University POLITEHNICA of BucharestFaculty of Engineering and Management of Technological Systems

Study Field - Industrial Engineering

CAD 2 PROJECT

Student: Rosioru Dragos

Coordinator:

- 2015 -Table of contents

Subjectx0. Initial dataxChapter 1. Structural - functional analysis of a mechanical partx1.1. 3D modelingx1.2. Part surfacesx1.3. Part and surfaces functionsx1.4. Material characteristicsx1.5. Weight calculationx1.6. Geometrical characteristicsxChapter 2. Structural - functional analysis of a mechanical assemblyx2.1. 3D modelingx2.2. Assembly componentsx2.3. Components characteristicsx2.4. Main function and functional treex2.5. Working conditionsxChapter 3. Structural - functional analysis of a sheet metal partx3.1. 3D modelingx3.2. Part surfacesx3.3. Part and surfaces functionsx3.4. Material characteristicsx3.5. Weight calculationx3.6. Geometrical characteristicsxReferencesxGraphical documentationx

No.Drawing nameDrawing numberFormat

1CAD6_01_20151

2CAD6_02_20152

3CAD6_03_20153

Subject

Initial data

Chapter 1 - Structural - functional analysis of a mechanical part

1.1. 3D modeling

1.2. Part surfaces

1.3. Part and surfaces functions1.4. Material characteristics

1.5. Weight calculation

1.6. Geometrical characteristicsChapter 2 - Structural - functional analysis of a mechanical assembly

2.1. 3D modeling

2.2. Assembly components

2.3. Components characteristics

2.4. Main function and functional tree

2.5. Working conditionsChapter 3 - Structural - functional analysis of a sheet metal part

1.1. 3D modeling

1.2. Part surfaces

1.3. Part and surfaces functions

1.4. Material characteristics

1.5. Weight calculation

1.6. Geometrical characteristics...1.1. 3D modeling

1.2. Part surfaces

SurfaceTypeManufacturing

S1Shaft 112.5mmh 62.5mmMilling/Iron Cast

S2Hole 56mmDepth 62.5mmDrilling

S3Chock 4mmx12mmDrilling

S4Plane Surface 300mmx112.5mm(left side)/87.5mm(right side)h 25mmMilling/Iron Cast

S5Shaft 87.5mmh 62.5mmMilling/Iron Cast

S6Hole 43.8mmDepth 62.5mmDrilling

S7Shaft 200mmh 25mmMilling/Iron Cast

S8Hole 56mmDepth 25mmDrilling

S9(x2)Guiding Hole 12mmDepth 6mmDrilling

S10PlaneMilling/Iron Cast

S11PlaneMilling/Iron Cast

1.2. Part surfaces

1.3. Part and surfaces functionsSurfaceTypeFunctions

S1Shaft 112.5mmh 62.5mmProtect

S2Hole 56mmDepth 62.5mmAssembly hole

S3Chock 4mmx12mmAssembly Gap

S4Plane Surface 300mmx112.5mm(left side)/87.5mm(right side)h 25mmProtect

S5Shaft 87.5mmh 62.5mmProtect

S6Hole 43.8mmDepth 62.5mmAssembly hole

S7Shaft 200mmh 25mmProtect

S8Hole 56mmDepth 25mmAssembly hole

S9(x2)Guiding Hole 12mmDepth 6mmGuide

S10PlaneProtect

S11PlaneProtect

1.4. Material characteristics

TypeGeneral CharacteristicsAlloyCommon ApplicationsTolerances for a 1/2" Dia. BarMaterial Cost FactorMachining Cost Factor

Alloy Steel.55% Ni, .50% Cr, .20% Mo, heat treatable and case hardening8620High stress applications needing the strength of an alloy.Cold drawn+.000/.0021.82.7

1.5. Weight calculationShapeVolume(cm3)Weight(kg)

Cylindrical tube621.280.3

Cylindrical tube375.848.6

Total

997.0

128.9

1.6. Geometrical characteristics

Chapter 2 - Structural - functional analysis of a mechanical assembly

2.2. Assembly components

2.3. Components characteristics Main materialsAlloy Steel 8620CharacteristicsHot rolled (HR) 8620 bar is a low carbon nickel chromium molybdenum alloy is a low cost steel with good carburized properties. The nickel content contributes to case toughness at high strength with above average core toughness. The chromium and molybdenum support the proper formation of carbides resulting in good surface hardness and wear. It is the most widely used carburizing alloy.ApplicationsTypical applications for hot rolled 8620 steel bar include gears, pinions, shafts, and other applications where it is helpful to have a steel that can be readily machined and carburized to controlled case depths.Typical Chemical PropertiesCarbon0.18 - 0.23

Manganese0.70 - 0.90

Phosphorus, Max %0.035

Sulfur, Max %0.040

Silicon0.15 - 0.35

Nickel0.40 - 0.70

Chromium0.40 - 0.60

Molybdenum0.15 - 0.25

Typical Mechanical PropertiesTensile Strength ksi75 - 95

Yield Strength50 - 80

Elongation in 2"17% - 35%

Reduction of area40% - 65%

Brinelle Hardness143 - 201

Prescribed heat treatmentsAustenitic Stainless Steels Conventional austenitic stainless steels will work harden with cold working, but cannot be hardened by heat treatment. Annealing is employed to optimize corrosion resistance, softness and ductility; consequently post-annealing may be specified after welding or thermal processing. This group is usually purchased in the annealed or cold worked condition.

Quenching and temperingQuenching and tempering provides the steel with high strength and ductility.Quenching and tempering is a heat-treatment method for high-quality heavy plates. Quenching and tempering consists of a two-stage heat-treatment process. Stage 1 includes hardening, in which the plate is austenitized to approximately 900C and then quickly cooled. The material is water-quenched in a quench unit, in which the plate is clamped to avoid warpage. Stage 2 consists of tempering the material to obtain the desired material properties. Quenching and tempering achieves an extremely fine-grained and homogeneous microstructure. Quenched and tempered steel is characterized by high strength and good ductility.Prescribed chemical treatmentPickling and Passivation

Stainless steel can corrode in service if there is contamination of the surface. Both pickling and passivation are chemical treatments applied to the surface of stainless steel to remove contaminants and assist the formation of a continuous chromium-oxide, passive film. Pickling and passivation are both acid treatments and neither will remove grease or oil. If the fabrication is dirty, it may be neccesary to use a detergent or alkaline clean before pickling or passivation.PicklingPickling is the removal of any high temperature scale and any adjacent low chromium layer of metal from the surface of stainless steel by chemical means.Where the steel has been heated by welding, heat treatments or other means, to the point where a coloured oxide layer can be seen, there is a chromium depleted layer on the surface of the steel underneath the oxide layer. The lower chromium content gives lower corrosion resistance. To restore the best corrosion resistant performance, the damaged metal layer must be removed, exposing a fully alloyed stainless steel surface. Mechanical removal may leave abrasive or other particles embedded (interfering with corrosion performance) or may be impractical, so chemical means are usually employed.Procedures incorporating pickling solutions of nitric (HNO3) and hydrofluoric (HF) acids remove the scale and the underlying chromium depleted layer and restore the corrosion resistance. Pickling solutions also remove contaminants such as ferrous and ferric oxide particles. Pickling solutions other than mixtures of nitric and hydrofluoric acids exist and can be used for specialised applications.Pickling pastes, where the solution is mixed with an inert carrier, are commonly used to treat selected areas such as welds.Pickling involves metal removal and a change or dulling in the visual brightness of the metal.Electropolishing is a useful alternative to pickling. Metal removal is achieved, but usually results in a bright, smooth and more highly corrosion resistant finish.PassivationPassivation is the treatment of the surface of stainless steels, often with acid solutions (or pastes), to remove contaminants and promote the formation of the passive film on a freshly created surface (eg through grinding, machining or mechanical damage).Common passivation treatments include nitric acid (HNO3) solutions or pastes which will clean the steel surface of free iron contaminants. Care must be taken in selecting and using passivation treatments to ensure the selected treatment will target the contaminant. Passivation will also aid in the rapid development of the passive oxide film on the steel's surface. Passivation does not usually result in a marked change in appearance of the steel surface.Both pickling and passivation solutions can employ dangerous acids that can damage both the operator and the environment if not handled correctly. Stainless pickling acids are highly corrosive to carbon steel.It is essential that all acids are thoroughly removed by rinsing the component after completing the process. Residual hydrofluoric acid will initiate pitting corrosion.It may be advantageous to neutralise the acid with an alkali before the rinsing step.ASTM A380 Standard Practice for Cleaning, Descaling and Passivation of Stainless Steel Parts, Equipment and Systemsis a valuable source of information on pickling and passivation treatments. Other sources of information may be obtained by contacting ASSDA.The corrosion resistance of the stainless steel is affected by the roughness of the surface after polishing, with a marked decrease of the corrosion resistance as the surface roughness increases above a Ravalue of about 0.5 micrometres. This roughly corresponds to the surface produced by grinding with 320 grit abrasives.Either passivation or electropolishing can be used to improve the corrosion resistance of mechanically polished surfaces.

2.4. Main function and functional tree

2.5. Working conditionsTemperature stability 2C

Maximum hot inlet temperature75 C

Inlet temperature range 50 C 70 C: hot supply5C - 25C: cold supply

Maximum working pressure20 bar: statistic

Minimum working pressure0.1 bar: dynamic

Working pressure range0.1 2.5 bar: low pressure12.5 20. bar: high pressure

Chapter 3 - Structural - functional analysis of a sheet metal part

1.1. 3D modeling

1.2. Part surfaces

S1 Plane 2x25mm,35mm, thickness 2mmS2 Hole 10mm

S3- Hole 14mm

1.3. Part and surfaces functions

To Grip and to stabilize a part

1.4. Material characteristics

Steel 1137

Higher carbon, higher strength, direct hardeningHigher stress applications, gears, shafts, studs, etc.Cold drawn+.000/-.003

Physical PropertiesMetricEnglish

Density7.87g/cc0.284 lb/in

Mechanical PropertiesMetricEnglish

Hardness, Brinell163163

Hardness, Knoop184184

Hardness, Rockwell B8484

Hardness, Vickers170170

Tensile Strength, Ultimate550 MPa79800 psi

Tensile Strength, Yield450 MPa65300 psi

Elongation at Break12 %12 %

Reduction of Area35 %35 %

Modulus of Elasticity200 GPa29000 ksi

Bulk Modulus160 GPa23200 ksi

Poissons Ratio0.290.29

Shear Modulus80.0 GPa11600 ksi

Izod Impact50.0 J36.9 ft-lb

64.0 J47.2 ft-lb

83.0 J61.2 ft-lb

Electrical PropertiesMetricEnglish

Electrical Resistivity0.0000170 ohm-cm@Temperature 20.0 C0.0000170 ohm-cm@Temperature 68.0 F

Thermal PropertiesMetricEnglish

CTE, linear 11.5 m/m-C@Temperature 20.0 C6.39 in/in-F@Temperature 68.0 F

12.2 m/m-C@Temperature 0.000 - 300 C6.78 in/in-F@Temperature 32.0 - 572 F

13.9 m/m-C@Temperature 0.000 - 500 C7.72 in/in-F@Temperature 32.0 - 932 F

Specific Heat Capacity0.472 J/g-C0.113 BTU/lb-F

Thermal Conductivity51.9 W/m-K360 BTU-in/hr-ft-F

Component Elements PropertiesMetricEnglish

Carbon, C0.32 - 0.39 %0.32 - 0.39 %

Iron, Fe97.79 - 98.25 %97.79 - 98.25 %

Manganese, Mn1.35 - 1.65 %1.35 - 1.65 %

Phosphorous, P