~ Practical testing of Chro Moly 4130 tubes andDacal 800 DP-tubes

KNOWLEDGE SERVICE CENTER

SSAB

SSAB X TECHNICAL REPORT

ear Reg.nr

100455

Knowledge Service Center NI.97PF.1O.0712 ITitle: Edition date Project + PT -

Practical testing of Chro Moly 4130 tubes 2010-11-29 ATlO0709and Dacal 800 DP-tubes Edition department - AV = Author + AU

FUT Peter FalkEditior: Joachim LarssonJoachim LarssonClienUEnterprise/lnstitution + co

Number of pages: Summary + 6 pages ME Racing, SwedenKeywords:Bil, Racing, Chassie, Ror, Dacal, Chrome Moly

SummaryME-Racing is investing the possibilities to use tubes made from Dacal 800 DPinstead 4130 Chrome Moly tubes in the chassis of one prototype Pro Mod car.

SSAB has carried out tensile testing, testing of T-joints and Three PointBending for both Docol and CrMo-tubes.The conclusions to be drawn are:

• The mechanical properties of the Docal 800 DP-tubes are very similar tothe 4130 Chome Moly tubes. The Docol tubes have slightly lower yieldstrength but higher tensile strength. The elongation values of the Docol-tubes are better than in the 4130 Chrom Moly tubes.

• The Dacal-tubes showed a better behaviour at fracture compared to theCrMo-tubes.

• The results from the tests of the welded T-Joints were quite similar eventhough the thickness and the diameter of the Docol tubes were smaller.

• In the Three Point Bending the relatively small difference in dimensionsof the tubes were significantly influencing the results. The Dacal-tubesshowed a lower initial stiffness compared to the CrMo-tubes and hence alower maximum load and energy absorption. Identical dimensions wouldhowever most probably result in equivalent performance at Three PointBending.

• The CrMo-tube with the locally reduced thickness positioned at threeo' clock showed reduced performance at Three Point Bending.

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SSABKnowledge Service Center97 SEMDlB Peter Falk

2010-11-29 100455NI.97PF.IO.007122(7)

1 INTRODUCTIONME-Racing is investing the possibilities to use tubes made from Docol 800 DPinstead 4130 Chrome Moly tubes in the chassis of one prototype Pro Mod car.In order to find out if this is possible SSAB has made a number of tests tocompare the differences in the behaviour in the two different materials. Thetests were performed in three different ways to find out the behaviour and theparameters of the different tubes.To be able to compare the two different types of tubes we chose to pick asequal dimensions as possible, see the table below:

Material Outer Dia. Wall thickness4130 Chrome Molv 41,27 mm II 5/8") 2,11 mm (0,083")Docol 800 DP 40,0 mm 2,Omm

Since the dimensions are slightly different this will be an advantage for theChrome Moly tubing in this stage since they have bigger diameter as well asgreater wall thickness.

The tests performed were:• Tensile testing• Tensile testing of welded T-Joints• 3 point bending

2 TENSILE TESTINGThe tensile testing of the tubes showed a completely different behaviour on thetwo different types of tubes. The Chrome Moly tubes burst in a spiral patternsee figure I. In order to get accurate elongation values manual evaluation wascarried out on the 4130 tubes. The Docol 800 DP tubes showed global neckingprior to fracture indicating a more ductile behaviour, see figure I.

The mechanical properties of both types of tubes are found in figure 2.

55AB 2010-11-29 100455N1.97PF.1O.007123(7)

Knowledge Service Center97 SEMDIB Peter Falk

(,Mo-S

(,Mo-G

Doeol800-1Docol800-2

-Docol800-3(,Mo-4

1

900

800

700';;" GOO"-~~~ 500;'"'".E 400;;;.,<:'ill 300<:w

200

100

o0,0% 2,0% 4,0% 6.0% 8,0% 10,0% 12,0% 14,0% 16,0%

Engineering strain

Figure 1: Tensile tests of the tubes.

Test Test Area RpO,2 Rm A5 A50mm A80mm Remarknr direct. min' N/mm2 Nlmm2 % Nlmm2 %

1 234,63 668 832 19 26 20 Docol800 DP

2 236,68 661 826 20 26 21 "

3 236,12 660 825 17 22 18 "

4 267,28 703 780 11 14 12 4130 erMo

5 261,78 673 773 "

6 261,50 681 771 "

Figure 2: Measured Mechanical Properties of the both types a/Tubes. The elongation waspossible to measure manually only on one erMa-tube.

SSAB 2010-11-29 100455N1.97PF.1O.007124(7)

Knowledge Service Center97 SEMDlB Peter Falk

3 TENSILE TESTING OF T-JOINTSIn this test two tubes were tig welded together in aT-Joint. The free ends were500 mm long in all directions. The tensile load was applied in 45 degrees on theshort tube welded to the longer one, see figure 3.

Force

Clamp

Figure 3: The set up in the Tensile Testing Machine

,;-CrMo. ,p ,,-

-CrMo.2

!'F/~~ " --CrMo.3

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•... -::; CrMo.5

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16

14

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2001801601408040 80 100 120Deflection [mm)

Figure 4: Tensile T-jopint tests of the 4130 erMa tubes. The two lower values are due todifferent angle of the clamps in the Tensile testing machine.

oo

SSAB 2010-11-29 100455N1.97PF.1O.007125(7)

Knowledge Service Center97 SEMDIB Peter Falk

200160160140604020

~ h --Doco'.1A r •••..•f>b -00co1.2

~~ ::::--- U, --00coI.3

I~

~

-00co1.4

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o 80 100 120Defledlon [mm]

Figure 5: Tensile T-joint tests a/the Doco/BOO DP tubes. The two lower values are due todifferent angle of the clamps in the Tensile testing machine.

20~

18

16

14

12

~o..,:s...I

6

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200160

--Oocol.1

--DocoI.2--Docor.3

-00co1.4--Doco1.5--C,Mo.1--C,Mo.2-C,Mo.3--CrMoA

-C,Mo.5

160140604020 80 100 120D.n.etion [mm]

Figure 6: Tensile T-joint tests of the Doco/800 DP and the erMa tubes in the same graph.The two lower values on each type of tubes are due to different angle of the clamps in theTensile testing machine.

20

18

16

14

12

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6

4

2

00

As can be seen in figure 4-6 the performance of the two different types of tubesare equivalent when it comes to static strength of the T-joint, although thedimensions of the CrMo-tubes are greater than the Docol 800DP-tubes.

SSABKnowledge Service Center97 SEMDIB Peter Falk

2010-11-29 100455N1.97PF.1O.007126(7)

4 THREE POINT BENDING TESTSIn three point bending the difference in diameter and the thickness have a ratherbig influence of the result. Since the 4130 CrMo tubes have both biggerdiameter and greater wall thickness this will be an advantage for this tubes.The set up in the Bending Machine was 800 mm between the supports and theTool Radius was 150 mm, see figure 7.

The results are found in figure 8. As can be seen there is a significantdifference already in the initial stage. The smaller Oocol 8000P-tubes show alower stiffness (only depending on the geometry of the cross-section and theYoungs modulus) compared to the CrMo-tubes. In case of identical dimensionsof the tubes and hence equivalent initial stiffness the performance (peak loadand energy) most probably all tubes would have about equivalent performance.

The welds on the Oocol tubes were placed in O. 90 and 1800 to the appliedforce in order to investigate how the weld could affect the bending resistance.In the tests performed on the 4130 CrMo tubes the wall thickness was measuredon several places and since the thickness was found uneven we placed thethinnest part of the tube just as we did with the weld on the Oocol tubes.As can be seen in figure 6, the biggest influence in the results were when weput the thinnest wall thickness at 90 degrees from the applied load (kl 3 infigure 8) on the CrMo tube.

Figure 7: The set up in the Tree Point Bending test

SSABKnowledge Service Center97 SEMDIB Peter Falk

2010-11-29 100455N1.97PF.IO.007127(7)

Distance between supply 800 mmTool radius 150 mmTest speed 2 mm/sec

~ 14

12

10

SF 8~."'"0 6~

4

2

00 20 40 60 80

Deflection[mml100 120

r 0- _

minth kl12--CrMo.2.minth kl3

--CrMo-3min.th kl6

--00col-1weldkl12

--00col-2weldkl3

--00col-3weldkl6

140

Figure 8: Three point bending lest of the tubes.

5 CONCLUSIONS

• The mechanical properties of the Docol 800 DP-tubes are very similar tothe 4130 Chome Moly tubes. The Docol tubes have slightly lower yieldstrength but higher tensile strength. The elongation values of the Docol-tubes are better than in the 4130 Chrom Moly tubes.

• The Docol-tubes showed a better behaviour at fracture compared to theCrMo-tubes.

• The results from the tests of the welded T-Joints were quite similar eventhough the thickness and the diameter of the Docol tubes were smaller.

• In the Three Point Bending the relatively small difference in dimensionsof the tubes were significantly influencing the results. The Docol-tubesshowed a lower initial stiffness compared to the CrMo-tubes and hence alower maximum load and energy absorption. Identical dimensions wouldhowever most probably result in equivalent performance at Three PointBending.

• The CrMo-tube with the locally reduced thickness positioned at threeo' clock showed reduced performance at Three Point Bending.