Tensile Testing And Hardness Testing Of Various Metals

Transcription

Tensile Testing and Hardness Testing of Various MetalsTechnical Report Submitted to: Dept. of Industrial & Manufacturing EngineeringProf. Edward C. De Meter310 Leonhard BuildingThe Pennsylvania State UNiversityUniversity Park, PA 16802Submitted by:Team: 4Pavel Shusharin,Erik VenutiMatthew PrevostDavid HontzDate: 2/10/16

Table of ContentsMethodologyAnalysisAnalysis of data obtained with an extensometerAnalysis of true stress strain for ductile materials

Investigation MethodologyThe metals that were tested in the lab:Cold Rolled Annealed Steel6061 Aluminum1018 Hot RolledBrassCast IronOur group tested: Cold Rolled Annealed SteelThe measurements that were taken:1) Tensile Testa) Timeb) Positionc) Forced) Change in length2) Rockwell Hardness3) Brinell Hardness4) Pre Tensile Test measurementsa) Gage Widthb) Gage Thicknessc) Gage Length5) Post Tensile Dataa) Gage Widthb) Gage Thicknessc) Permanent Length Between Jaw Alignment MarksThe Mechanical properties that were derived:1) Young’s Modulus2) Engineering and True Strain at Yield point3) Ultimate Tensile Stress4) Engineering and True Strain at UTS5) Ductility6) Engineering and True Shear Strain7) True Strain at Fracture8) Measured and Predicted Max True Stress9) Strain Hardening exponent10) Strength Coefficient11) Predicted toughness

Analysis of data obtained with an extensometer.For each metal: Engineering stress strain plot with a figure caption Additional graph that shows a 0.2% offset and includes a trend for the linearportion of the graph Table with e , e , E, y (shear strain), UTS and ductility.0 u BrassFigure 1.1 Engineering stress strain plot for Brass The shape of this plot indicates this Brass is a ductile metal It does not appear the extensometer slipped during this tensile test

Figure 1.2 Engineering stress strain plot of the elastic region with 0.2% offsetTable 1.1 Table of mechanical properties of Brasse (in/in)0 e (in/in)u E (ksi)y (ksi)UTS (ksi)Ductility (%)0.00440.20581604238.047.935

6061 AluminumFigure 1.3: Engineering Stress vs. Strain plot for Aluminum SpecimenDuctility: 6061 Aluminum exhibits a large region of plastic deformation before fracturewhich is indicative of ductility.

Figure 1.4: Zoomed Engineering Stress vs. Strain displaying 0.2% offset for AluminumSpecimen.Extensometer: The data contains a slight discontinuity at the beginning of the test whichindicates that the extensometer slipped.Table 1.2 Mechanical properties of 6061 Aluminumϵ o (in./in.)ϵ u (in./in.)E (ksi)0.005370.09038605.9γ (ksi)35.417σ (ksi)UTS 41.544Ductility16%

1018 Hot Rolled SteelFigure 1.5 Engineering Stress vs Strain plot for 1018 Hot Rolled Steel

Figure 1.6 Zoomed Engineering Stress vs Strain plot of 1018 Hot Rolled Steeldisplaying 0.2% offsetComments:Based on this data, the 1018 Hot Rolled Steel specimen exhibits significant ductility dueto its large plastic deformation.The data shows a slight discontinuity at the beginning of the test, indicating that theextensometer slips for a brief moment.Table 1.3 Mechanical properties of 1018 Hot Rolled Steele (in/in)0 e (in/in)u E (ksi)y (ksi)UTS (ksi)Ductility.0035.0191233.141*10 651.6360.8933.0%

Cast IronFigure 1.7: Engineering Stress vs. Strain for Cast Iron SpecimenDuctility: The data shows almost no signs of plastic deformation which indicates thatCast Iron is not ductile.Table 1.4 Mechanical Properties of Cast Ironϵ o (in./in.)ϵ u (in./in.)E (ksi)N/AN/A15118γ (ksi)N/Aσ (ksi)UTS 6.8087Ductility0.5%

1018 Annealed SteelFigure 1.8 : Engineering Stress vs. Strain for the 1018 Cold Rolled SteelFigure 1.9: Zoomed Engineering Stress vs. Strain displaying the 0.2% offset and elasticregion.Comment: Based on this data, the 1018 Cold Rolled Steel specimen exhibits significant ductility due to its large plastic deformation.The data is very smooth and does not exhibit any discontinuities indicating that theextensometer did not slip during testing.

Table 1.5 Mechanical properties of 1018 Annealed Steelϵ o (in./in.)ϵ u (in./in.)E (ksi)0.0033730.221924128γ (ksi)31.84σ (ksi)UTS 44.46Ductility %42

Analysis of true stress strain for ductile materialsFor each ductile metal: True stress strain plot A table with y , ms maximum true strain), k, n, ps (predictedt t max (measured t max maximum true strain) and predicted toughness.BrassFigure 2.1 A true stress strain plot, including a flow stress equation and trendlineFor this metal, the predicted value for maximum true strength was reasonablyclose to the actual value. This measurement has an 18.6% error, which is slightly thanthe other metals tested.

Table 2.1. Mechanical properties evaluated from true stress strain ploty (ksi)t ms t max (ksi) knps t maxpredictedtoughness (in/in)38.478.7268.520.12264.0532.7e 00.00442in/ine 35%e f0.57549in/inσ t n/in)

AluminumFigure 2.2. True Stress vs. Strain plot for Aluminum SpecimenTable 2.2 Mechanical properties evaluated from true stress vs. strain plotγ t (ksi)κ (ksi)ηmeasuredσ (ksi)t max predictedσ (ksi)t max predicted toughness(lb*in./in. 3)35.60756.1760.094152.60546.9443.542141Comments:

1018 Hot Rolled SteelFigure 2.3. True Stress vs Strain plot for 1018 Hot Rolled Steel.The first (blue) data set represents strain data from 0 to ε . The second (red)0 data set represents strain data from ε to ε . The third data set (green) represents the0 u predicted failure point corresponding to ε and σ .f t max Table 2.3. Mechanical properties evaluated from true stress vs. strain plotyt(ksi)κ (ksi)ηε (in/in)f σ Predicted σ Stresst max t max Flow (ksi)(ksi)Toughness(lbf*in/in 3)51.8772.31.064.086361.834.84865.58The value for predicted σ was very close to the actual value obtained with thet max data, varying by only 3.75 ksi and yielding a mere 5.7% error.

1018 Cold Rolled SteelFigure 2.4. True Stress vs. Strain for the 1018 Cold Rolled SpecimenThe value for predicted σ was much less than the actual value obtained witht max the data. This is because the measured value takes into account the instantaneouscross sectional area, while the predicted value uses the original cross sectional area.The values vary much more for the annealed steel than the other materials because ofthe annealed steel’s high ductility.Table 2.4. Mechanical properties evaluated from true stress vs. strain plotyt (ksi)κ (ksi)ηε (in/in)f σ Predictedt max (ksi)σ t max Flow Stress (ksi)31.9572.4790.2016.350658.674181.3956

Analysis of data obtained with an extensometer.Cold Rolled Annealed steelFigure 1.3 Engineering Stress Strain plot for Cold Rolled Annealed Steel

Figure 1.4 Engineering Stress Strain plot of the elastic region with 0.2% offsete (in/in)0 e (in/in)u E (ksi)y (ksi)UTS (ksi)Ductility0.0390.17841011.238.3670.0222.16 %

Based on the data for the five specimens, the material that would be the easiest to forminto a shape would be 1018 Annealed Steel. It exhibited the highest ductilitypercentage (42%) and a relatively low yield strength (31.84 ksi). These properties makeit easy to plastically deform and form into a shape.For similar reasons, the Cast Iron sample would be the most difficult material toplastically deform and form into a shape. It exhibited a very low ductility percentage(0.5%) making it very difficult to plastically deform.Annealing is a process of heat treating a metal in a certain way that would improve itsmaterial properties. Mainly, annealing will increase ductility while decreasing hardness.These changes increase the formability of the annealed metal and it more workable.This is consistent with our data because of the two samples of 1018 Steel (hot rolledand annealed), the annealed specimen exhibited a higher ductility percentage by 9percent.Steel specimens have alloying elements present in their structure, meaning anincreased dislocation density. The increase in number of dislocations causes the steelsto yield in a two part fashion, resulting in an upper yield strength and lower yieldstrength. The anomaly is primarily found in steels due to the high number of interstitialdefects that the alloying process results in.

Hardness values for tested specimensTable . Hardness values for annealed hot rolled steel.Annealed hot rolledSteelRockwell B TestBrinell 10/500Hardness Test

Average51.8581.25Conversion table value5285Table . Hardness values for cold rolled annealed steel.Cold rolled annealedsteelRockwell B TestBrinell 10/500Hardness TestAverage99.7227.5Conversion table value95220Table . Hardness values for aluminum.6061 AluminumRockwell B TestBrinell 10/500Hardness TestAverage53.82595.6Conversion table value5487Table . Hardness values for brass.BrassRockwell B TestBrinell 10/500Hardness TestAverage71.1110.5Conversion table value71112Table . Hardness values for cast iron.Cast IronRockwell B TestBrinell 10/500 HardnesstestAverage96.1201.5Conversion97184

Table . Hardness values for hot rolled steel.Hot Rolled SteelRockwell B TestBrinell 10/500Hardness TestAverage83.7137.5Conversion table value84140Comments on the agreement of the average hardness values measured to that ofthe conversion tables:All the measurements closely correlated to the values given in the conversion tables ofASMI. Even though there is some deviation it is negligible considering all thecomponents that went into testing, from slight deviations of the internal structure ofmaterials, to human error.Tables. The info is taken from the International ASTM ti%20(in%20engleza).pdf

10.02.2016 · 1)Tensile Test a)Time b)Position c)Force d)Change in length 2)Rockwell Hardness 3)Brinell Hardness 4)Pre Tensile Test measurements a)Gage Width b)Gage Thickness c)Gage Length 5)Post Tensile Data a)Gage Width b)Gage Thickness c)Permanent