Due Date: 12/20/2000
Submission Date: 12/20/2000

Abstract -Page 2
Introduction
–Page 2
Objective
–Page 3
Procedure -Page 3
Analysis -Page 3
Results -Page 4
Discussion -Page 7
Conclusions -Page 7
Page 9- Detailed Data, Analysis and Results
Pages 9- Glossary of Terms
Page 12- Equipment
Page 13- Detailed Test Procedure
2

A tensile test was done on 4 specimens of 304 Stainless Steel and 2 specimens of 1018
CF Steel, to ascertain if a better alloy for tracks in the northeast corridor could be found. The properties needed for this material would be equal to or greater than the material presently being used, 1018 CF Steel in terms of ultimate strength. The new material would have extended ductility range, a higher modulus of resilience, and a higher modulus of toughness.
Once tests were completed, the results showed that 304 Stainless Steel demonstrated a 10 to 20 percent increase in modulus of resilience, a 15 to 50 percent increase in modulus of toughness, and a more consistent ultimate strength
There has been some concern expressed as to whether the present material being used for the tracks in the northeast corridor, 1018 CF Steel, will stand up to the new high speed rail car we are building. In response to this, after viewing computer simulations of various materials’ energy characteristics, a tensile test was done. 304 Stainless Steel was the material most likely to show an improvement in overall lateral strength, which prevents failure in corners where stress is greatest. It was also the most likely to show improvement in lateral strength and stiffness in the form of ultimate strength and resilience. Energy capacity in the form of modulus of toughness to prevent sudden failure without warning is the characteristic being sought.
3

This tensile test is being done on a Tinius Olsen machine to calculate ultimate load, fracture load, through standard calculations and a load vs. elongation graph taken directly off the machine. Original diameter, final diameter, original length, and final length are be measured with a dial caliper and recorded. From this data results are calculated to determine, ultimate strength - ultimate load / original area, yield strength by 2% offset - by constructing a line along the linear portion of a blow up of the load vs. elongation graph, modulus of resilience - by calculation of area under linear portion of curve, modulus of toughness - by calculation of entire area under curve. These results will be tabulated and then converted into charts for ease of comparison. Results will be used to determine if a better alloy can be used for track stock for the northeast corridor.
Measure the diameter , then punch and measure the gauge length of specimen
Put specimen in grips apply pre-load
Set up plotter
Install extensometer on specimen
Apply load slowly until one rotation of drum is nearly complete
Remove extensometer
-
Continue loading until fracture, record data i.e.: final diameter, final length, and appearance of fracture.(Refer to appendix page 9 for complete procedure)
Strength ultimate = W - load ultimate / Area original
4

Modulus of Resilience = ½(Base)(Height), under proportional limit.
Modulus of Toughness = M of R + (# of boxes)(in-lb/in 3 /box), in load Vs elongation graph.
Length final – length original, = measured change.
A o
=  r
2
* D
Yield Strength – S y strength
at witch a material yields found by construction.
E =  /  Modulus of elasticity = Stress / Stain within elastic range.
All Four Specimens of 304 Stainless Steel were within 400 PSI of 92 KPSI
The ultimate strength of 1018 CF Steel compared to 304 Stainless Steel varied by 3 KPSI.
Modulus of resilience for 304 Stainless Steel proved to be very small; these started to yield almost immediately. However specimen 10 exhibited an M of R of 22.48 in lb/in
^3
.
Comparatively the 1018 CF Steel held to within 2 in lb/in ^3 of 40 in lb/in ^3 , demonstrating more elastic capability, which is not an admirable quality for train tracks. The four specimens of 304
Stainless Steel demonstrated a modulus of toughness between 33K and 61 Kin lb/in^3. Where the 1018 CF Steel had a maximum of 17K.Yeild strength for 304 Stainless Specimens was within 10% of 55 KPSI, whereas the 1018 CF Steel yielded at 75 KPSI plus or minus 3 KPSI.
5

1018 CF Steel
1018 CF Steel
304 Stainless
304 Stainless
304 Stainless
304 Stainless
9 75
12 78
1
8
63
48.5
10
15
52
51
3
89
92
92
92
91.7
92
38.6
42
0.15
0.2
22.48
0.2
Ultimate Strength In the 304 Specimens (Su) were found to be Spec01 - 92 KPSI, Spec08 - 92
3
17338.3
8127
61800
46188
33014.97
42150
KPSI, Spec10 - 91.7 KPSI, Spec15 - 92 KPSI.
In 1018 CF Steel (Su) were found to be Spec 9 - 89 KPSI, Spec12 - 92 KPSI
80
Ultimate
Stength
KPSI
60
40
20
120
100
0
1
304 Stainless
8
304 Stainless
10
304 Stainless
15
304 Stainless
Speciman And Type
9
1018 CF Steel
12
1018 CF Steel
6

Yield Strength by 2% Offset for 304 Stainless were found to be Spec01 - 63 KPSI,
Spec8 48.5 KPSI, Spec10 - 52 KPSI, Spec15 - 51 KPSI
1018 CF Steel was found to be Spec09 - 75 KPSI, Spec12 - 78 KPSI.
304 Stainless Vs 1018 CF Steel
Yeild Strength by 2% Offset
Sy
.2
%
K
PS
I
100
90
80
70
60
50
40
30
20
10
0
1
304
Stainless
8
304
Stainless
10
304
Stainless
15
304
Stainless
Specimen and Type
9
1018 CF
Steel
12
1018 CF
Steel
Modulus of Resilience for 304 Stainless was found to be Spec 01 .15 in lb/in
^3
, Spec
08 .2in lb/in ^3 , Spec 10 22.48 in lb/in ^3 , Spec 15 .2 in LB/in ^3 .
And for 1018 CF Steel Spec 09 38.6 in lb/in
^3
, Spec 12 42 in lb/in
^3
304 Stainless VS 1018 CF Steel
Modulus of Resiliance
20
10
0
-10
60
50
40
30
1
304 Stainless
8
304 Stainless
10
304 Stainless
15
304 Stainless
Specimen and Type
9
1018 CF Steel
12
1018 CF Steel
7

Modulus of Toughness 304 Stainless was found to be Spec01 61800 in lb/in
^3
, Spec 08
46188 in lb/in
^3
, Spec 10 33014 in lb/in
^3
, Spec 15 42150 in lb/in
^3
,
And for 1018 CF Steel Spec 09 17338 in lb/in
^3
, Spec 12 8127 in lb/in
^3
.
80000
70000
60000
M
o f
T
i n
l b
^3
/i n
50000
40000
30000
20000
10000
0
9
1018 CF
Steel
12
1018 CF
Steel
1
304
Stainless
8
304
Stainless
Specimen and Type
10
304
Stainless
15
304
Stainless
The M of R results for Specimens 1,8,15 were recalculated because errors were found in calculations. Specimen 10 was suspect as it is much higher than the others are. After checking calculations no error could be found. So this specimen was included. After viewing the load vs. elongation graph, it appears this specimen demonstrated an unusually long linearity
.
Comparing 304 Stainless with 1018 CF Steel. It can be seen from the chart of M of T that 304 Stainless has a greater overall ductility. It can be seen from the chart of ultimate
8

strength that 304 Stainless has a more consistent overall strength. And, therefore, under loaded conditions will perform with a more consistent maintenance ratio (time to replacement or repining from stretch). Providing evidence before failure allowing for planed maintenance. Even though 304 Stainless yields at a lower point, with a 10% safety factor added in, it still maintains a 30 plus KPSI rate. It should be noted that 304 Stainless maintains an ultimate strength 75% of the time within 10% of 92 KPSI. Which is an important consideration when planing for unexpected overloads. It can be seen from M of R that 304 Stainless has virtually no elastic capability. This is an indication of its stability under load. At this time a scale mock up test should be done to test under conditions. I.e.: x and y lateral velocity and prolonged durability.
304 Stainless demonstrates a 100% increase in the modulus of toughness. It will be noted that 304 Stainless is directly comparable to 1018 CF Steel in ultimate strength at 92 KPSI
+- 2%.
Tolerance of 10% used to compensate for operator error and molecular variations.
Corrected Results All but Spec10 M of R results were recalculated.
9

Available at: s/mt/114/2000
10

PROPORTIONAL LIMIT : Th e maximum stress at which stress and strain remain directly proportional. The proportional limit is determined from the stress-strain curve by drawing a straight-line tangent to the curve at the origin and noting the first deviation of the curve from linearity. The value obtained for the proportional limit depends upon the precision of measurement of strain and stress and upon the scale of the plot. It is not widely used in engineering calculations.
ELASTIC LIMIT: The maximum stress, which the material can withstand without causing permanent deformation. An exact determination of the elastic limit requires loading to successively higher stresses followed by unloading and measurements to detect permanent deformation. Its actual value, like the proportional limit, is dependent upon precision of measurement. This and the difficulty of determination severely limit its engineering usefulness.
It cannot be determined from data collected for this experiment.
YIELD STRENGTH: The stress at which a material exhibits a specified limiting permanent set. Below the elastic limit, the stress - strain relationship in loading and unloading are for practical purposes identical. Therefore it is not necessary to unload a specimen in order to determine the yield strength. Rather, a line parallel to the initial straight-line portion of the curve is constructed. The construction is displaced from the origin of the curve by an amount equal to the specified permanent set. The stress at the intersection of the parallel line with the stress-strain curve is the yield strength. The offset most commonly used is at 2% strain or 0.002 in./in. The yield strength is a practical measure of the limit of elastic action. It is always greater than the elastic limit, and is not nearly as sensitive to errors in the strain limit as the elastic limit.
YIELD POINT : A property which is encountered in soft, unhardened steels, and a few other alloys. Like the yield strength, it is also an indication of the limit of elastic action. The yield point is a stress at which there first occurs a marked increase in strain in the absence of an increase in stress. In fact there are usually two yield points: an upper and lower yield point. The upper yield point would be considered as THE yield point in this experiment. The yield point and yield strength are approximately equal.
TENSILE STRENGTH or ULTIMATE STRENGTH: These two are synonymous. It is calculated by dividing the original cross section of the specimen into the maximum load sustained by the specimen.
RUPTURE STRENGTH or FRACTURE STRENGTH: These are determined by dividing the original cross-section of the specimen into the load sustained at rupture. This load will be less than the maximum load because the cross section of the specimen is reduced after the maximum load is reached. The reduction of cross section produces an hourglass shape and is known as necking or necking down.
11

MODULUS OF ELASTICITY: This is also known as stiffness of the material. The modulus of elasticity in tension is known as Young's Modulus. It is the constant of proportionality between stress and strain at stresses below the proportional limit:
E = S / e
Where S is stress, e is strain and E is the modulus of elasticity. E is found by measuring the slope of the straight-line portion of the stress-strain curve:
E = ( S
1
- S
2
) / ( e
1
- e
2
)
If the stress-strain plot goes through 0,0 at the origin, and if the initial portion of the plot is a perfectly straight line, then the modulus of elasticity can be determined from any stress below the proportional limit and the corresponding strain simply by dividing the stress by the strain.
MODULUS OF TOUGHNESS: The ability of the material to absorb energy up to the point of rupture. It is determined by measuring the area under the stress-strain curve. This is not an exact indication of toughness because the specimen does not strain uniformly over its length, and hence does not absorb energy uniformly throughout its volume. The units of toughness are found by multiplying stress by strain, that is ( pounds / square inch ) X ( inches / inch ) to give inch-pounds / cubic inch of energy absorbed per unit volume.
DUCTILITY: A measure of the amount of deformation that a material can withstand without breaking. It is expressed as the Percent Elongation or Percent Reduction In Area at Fracture .
The elongation at rupture is determined from l / l o
where l is the change in length, i. e. l f
- l o
, final length - the original length. The elongation is usually expressed as a percentage:
% Elongation = 100 x l / l o
The reduction of area is also expressed as a percentage, and is calculated from:
% Reduction of Area = 100 x A / A o
Where A is found from A o
- Of, A o
being the original area and Of being the final area.
FRACTURE APPEARANCE: The appearance of the fracture of tensile test bars is related to composition and previous history of the specimen. Ductile metals and alloys develop a cup and cone or partial cup and cone fracture. Low-carbon, annealed steels fracture in this fashion. If the steel is high-carbon steel, or if it has been hardened by heat treatment it will tend to develop a star fracture. Cast iron, which is devoid of ductility, does not neck down and has a fracture surface, which tends toward a plane at right angles to the direction of loading.
12

1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
13

- Measure and record the original diameter of the specimen in inches.
- Mark the end points for a gage length of 2.0 in.
- Measure and record the distance between the two end points.
- Using the load and unload valves, locate the table / tension crosshead so that the red mark is raised about one inch from the stationary table.
- Put the specimen in the grips of the Tinius-Olsen testing machine. Use a matched pair of shoulder-gripping jaws at each end of the specimen (each jaw is numbered for identification). Use the hand crank to move the adjustable crosshead to allow insertion of the specimen.
- Select the desired load range. For this test, the highest load range is recommended
Low - 3000 lb. max
Med. - 12,000 lb. max
High - 60,000 lb. max
- Zero the load dial pointer using the adjusting knob for the load range being used.
- Prepare the drum recorder to record load and elongation. You are controlling the magnification of your graph from the recorder:
For load measurement:
Full range - load on graph is actual load
1/2 range - load on graph is 2x actual load
For elongation:
Magnification Selector Smallest division on
Range Elongation scale
----------------------------------------------
A
----------------------------------------------------
7.6X10
-4 inch
3.8X10
-4 inch B
C 1.9X10
-4 inch
- For this test, 1/2 range and magnification C is recommended. Remember to record the range and magnification on the plot when the test is completed.
- Extensometer Instructions
1 - Make sure that power is off and standby is off at the recorder.
2 - Turn recorder reset to full counter-clockwise position. Make sure that the extensometer zero is at the 6 o'clock position on the cam.
3 - Turn the power switch on.
4 - Set magnification selection to "C" for steel.
5 - Hand crank small preload into specimen.
6 - Install extensometer onto specimen.
Force the jaws apart by pushing against the spring-loaded bracket. At the same time make sure that the transformer armature rocker arm is up against the cam when positioning the extensometer. Use two hands.
14

7 - Turn the standby switch on. The recorder drum will rotate.
15