Reading Assignment
- 10th edition Ch 2 Including:
- Static Properties
- Dynamic Properties
- Temperature Effects
- Machinability, Formability Weldability
- Fracture Toughness
- Physical properties
- Testing Standards and Concerns
- Stress-Strain Study guide/quiz
Tensile Testing
Testing Setup (See ASTM E8 / E8M – 09 Standard Test Methods for Tension Testing of Metallic Materials)
- Specimen
- Grip, attachment
- Extensometer
- Gage Length
- Cross-Sectional Area of Specimen
Stress Strain Diagram
- Modulus of Elasticity
- Elastic Limit
- Plastic Deformation
- Fracture
- Elongation at Fracture
- Typical Diagrams for Various Materials
- Metal
- Elastomers
- Glass, Ceramic, Concrete
Properties Obtained from the Tensile Test
- Elastic Limit
- Proportional Limit
- Neither of these is easy to measure precisely, so
- .2% Offset Yield Strength
- Yield Point
- Upper Yield Point
- Lower Yield Point
- Stiffness
- Modulus of Elasticity
- E is Young’s Modulus
- Higher E, Stiffer Material
- Tensile Strength
- Top of the stress-strain curve
- Necking is disregarded using engineering stress
- Necking is an indication of ductility
- Poisson’s Ratio
- Relates longitudinal deformation to lateral deformation
Effect of Temperature
Typical Specimens
Fractures
Compression Testing
Deformation Modes in Compression
- Buckling
- Shear
- Double Barreling
- Barreling
- Uniform Compression
- Compressive Instability
Hardness Testing
Macroindentation
- Brinell Hardness
- Rockwell
- Vickers
Microindentation
- Knoop
Brinell Hardness Test (ASTM E10)
5 or 10 mm Ball Indenter under 500-3000 kgf load, indentation measured with a microscope.
Hardnessload divided by surface area of indentation.
Rockwell Hardness Test (ASTM E18)
- A series of scales (A, B, C…H)
- Steel 1/16 or 1/8 ball, or diamond tip brale.
- Application of 10 kg Minor Load
- Application of Major load
- Major load removal -> reading depth of penetration
e.g., C scale is brale indentor, 150kg major load.
(Example reading is RC 60)
Rockwell Test Sequence
Vickers Hardness Test (ASTM E92)
Uses a 136 degree diamond pyramid and loads between 1 and 120 kg.
Value is load divided by surface area.
Advantages
- A single scale for all values
- Simple
- Fast
- Little surface prep
- Small marks
- Inexpensive
Knoop Hardness Test (ASTM E384)
- Elongated pyramidal indenter
- Uses Vickers machine
- Can be used where other hardness tests cannot fit.
- Tests can be conducted closer together.
- Can be used on thin coatings.
Disadvantage in conversion.
Other Hardness Tests
- Durometer
- File “Test”
Hardness Conversions (ASTM E140)
Dynamic Loading and Impact Testing
Charpy Test
Izod Test
Tension Impacts
Drop Tests
Notched Bar Impact Testing (ASTM E23)
- Result is ft-lb of energy or Joules absorbed
- Lateral Expansion
- Percentage of Shear Fracture
- Flat fracture is brittle
- Bent, stable fracture is ductile
- Both can usually be seen across the fracture zone
Charpy V-Notch Tests
- Specimen of fixed dimensions
- Notch geometry, Notch Sensitivity
- Supported on the Ends
Izod Test
- Similar specimen shape and test, but with cantilever orientation.
Additional Information
ASTM E8 / E8M – 09 Standard Test Methods for Tension Testing of Metallic Materials
A356/A356M Specification for Steel Castings, Carbon, Low Alloy, and Stainless Steel, Heavy-Walled for Steam Turbines
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
B557 Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
B557M Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products (Metric)
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E83 Practice for Verification and Classification of Extensometer Systems
E345 Test Methods of Tension Testing of Metallic Foil
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1012 Practice for Verification of Test Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application
E1856 Guide for Evaluating Computerized Data Acquisition Systems Used to Acquire Data from Universal Testing Machines
A series of scales (A, B, C…H)
Steel 1/16 or 1/8 ball, or diamond tip brale.
Application of 10 kg Minor Load
Application of Major load
Major load removal -> reading depth of penetration
e.g., C scale is brale indentor, 150kg major load.
(Example reading is RC 60)
