schaeffler technology rapport om skader på ic4 aksellejekasser, 28. marts 2011

Schaeffler TechnologiesGmbH & Co. KGGeorg-Schfer-Strasse 3097421 Schweinfurt (Germany)Phone +49 9721 91-0Fax+49 9721 91-3435 Internetwww.fag.comRegistered Place of Business:Herzogenaurach (Germany)Resp. for Commercial Register:AG Frth HRA 9349

General Partner:Schaeffler GmbHRegistered Place of Business: Herzogenaurach (Germany)Resp. for Commercial Register:AG Frth HRB 12116

Executive Officers:Dr. Jrgen M. Geiinger, Klaus Rosenfeld,Prof. Peter Gutzmer,Rainer Hundsdrfer, Norbert Indlekofer,Oliver Jung, , Kurt Miirlach,Dr. Peter Pleus, Dr. Gerhard Schuff,Robert Schullan

Bank:Commerzbank NrnbergBLZ 760 800 40 Account 121046400BIC DRES DE FF 760IBAN DE35 7608 0040 0121 0464 00

Schaeffler Technologies GmbH & Co. KG P.O. Box 12 60 97419 Schweinfurt (Germany)

Schaeffler ItalyAttn. to: Mr. PremoliStrada Provinciale 229, km 17I-28015 Momo (NO)

Italy

Your ref., your letter dated Our ref., our letter dated Phone +49 9721 Fax +49 9721

5618, Dec. 2010 [email protected] 91-6778 91-2303

Inspection Report No.: 213207365 March 28th, 2011

Customer: AnsaldoBredaAttn. to: Mr. D. SpinelliPistoiaItaly

Final Customer: DSB Fjern & RegionaltogAttn. to: Mr. Jan ElgaardTrain Maintenance, Technical departmentSonnesgade 21DK-8000 Aarhus CDenmark

1. Returned goods

Reference: Quality Service Order dated Dec. 20th, 2010;Customer Visit on Feb. 23rd, 2011

Quantity and type: 2 TAROL-150/250-807581 (Pos. 1 and 2)2 Z-176466-ANM150T(Complete axle boxes, supplier AWS)

Bearing designations: FAG TAROL 150/250-USA-B-04-93404 (1)FAG TAROL 150/250-USA-B-04-93962 (2)

Condition at delivery: Used, delivered in a large wooden box

Application: Railway axle boxes

Operating Conditions: Distance travelled: 102,000 kmAxle loads: Max. 21.3 t per axleTrain speed: Max. 180 km/hLubrication: Grease L222Operating temperature: Unknown

Customers request/complaint: Visual inspection; What is the reason for the housing base breakage?

of our letter dated March 28th, 2011

The case of the lower arm (code GHU.176466 A D01 - 03-024C) is broken in two areas. For detailed analysis the case was forwarded to the department CorporateMaterials.

Also, the shock absorbers were forwarded to the vehicle module testing department for closer investigations.

The TAROL-bearings were cleaned, disassembled and subjected to a visual ins-pection. Both bearings show similar characteristics, therefore findings and assess-ment are summarized in the following.

2. Findings

2.1 Visual Inspection

2 TAROL-150/250-807581Outer rings:There are no distinct loaded zones in the raceways. The racetracks show isolated particle indentations on the one hand and circumferential scores on the other hand, see Figs. 4-8 (bearing 1) and Figs. 23-25 (bearing 2). The particle indentations of bearing 1 are partly in a lined formation in axial direction, see Fig. 6. Both bearings show strong local fretting corrosion characteristics, whereas bearing 1 is more affec-ted.

Inner rings:The racetracks are slightly dulled and show a few isolated indentations. Otherwise, the inner rings show normal running and seating characteristics.

Rollers:Circumferential, feelable score marks on the racetracks, see Figs. 15 and 28.

Cages:Normal contact marks in the pockets.

Spacer rings, Sealing caps and backing rings:There are no abnormalities noticeable.

2 Z-176466-ANM150TStrong corrosion characteristics cover all base parts. The housing base 5618 VS is broken in axial direction in each case in the areas of the mounting suspensions, see Figs, 36-38. The fractured areas are covered with corrosion, however we found some smoothed in areas. On the outside there is a beginning crack on the reinforcement bar (Fig. 34). Strong corrosion characteristics in the inside diameter.

Please note: The housing base and top pieces of the journal roller bearing are fixed with 4 screws per axle box (8 screws in total). 7 screws of are hexagon screws M16x110 ISO 4014, the tightening torque is 130 Nm +/- 10 Nm. 1 screw is a fittingscrew M20x110 DIN 609, the tightening torque is 260 Nm+/-10 Nm.


The hexagon fitting screw was fitted in the housing base 5618 VS the fractured housing side. Fitting marks can be seen in the bore of pos. d (see overview drawing and section D-D below). Also the washer is positioned centrically (see Fig. 82) on the contrary to the other hexagon screws M16x110 ISO 4014 (see Figs. 83 und 84), positions a, b and c. This indicates that the screws were mounted in the correct positions.

The red dashed lines indicate the approximate location of the case breakage (left: crack 1, right: crack 2 as noted in Fig. 36).

The housing base of the other side (across from the damaged base part) is covered with crack detection substance (white and pink in colour). There are no cracks detected neither on the reinforcement area nor in the areas of the mounting sus-pension, see Figs. 53-56.

The housing upper components also show strong corrosion characteristics, especial-ly in the areas of the TAROL-housing seating. Also, the contacting sides of the TAROL-housings show corrosion corresponding to the characteristics of the neigh-boring parts. In the inside diameter, in the area of the TAROL-bearings seat, axial and circumferential seating marks and also fretting corrosion can be detected.

1 2

a

b c

d


Please note: One housing base of train No. 5608 (damage detected Feb. 2010) was delivered along. This part was already inspected by the company FORCE TECHNO-LOGY. Therefore only a visual inspection was carried out. One side of the housing base in the area of the mounting suspension was broken off (same damage pattern as the inspected case in this report, yet only one side); the part with the screw holes was not returned.

Additional information supplementary investigation regarding the allocation of the bearings - carried out on March 28th, 2011:By comparing the corrosion characteristics of the TAROL-150/250-807581 bearings, the bearing housings and the housing bases we were able to identify the allocation of the bearings. Bearing 1 (the bearing with particle indentations partly in a lined formation in axial direction) was fitted in the broken housing base. The lined-up particle indentations were located in the beginning of the loaded zone and towards the outside (non-wheel-side), see the complementary Figs. 85-88 on pages 37 and 38.

2 Shock absorbersOne shock absorber (V side) was disassembled by the customer at delivery. There is a score mark on the outside, see Fig. 67. In addition, a pressured polished area on the piston rod, located approximately in the centre, can be seen (Fig. 68). The H-sided damper is still assembled, yet scored on the outside surface.

Covers, sealing rings, gear wheels, screws, bolts, shims and o-ring sealPlease see the description of the pictures of Figs. 71-81.

2.2 Material Investigation

The fracture surfaces were investigated. The initial fractures seem to start from the outer diameter of the housing (fracture #1, shock absorber side). The material does not show any de-formation or necking in the area of fractures, which is a distinct hint for a fatigue fractures. The fracture surface was investigated via SEM: in some places fatigue lines near the grain boundaries are visible, see Fig. 45; these also areindications for fatigue fractures.

One piece of the housing was cut out and broken in a press as a laboratory fracture to compare the structure. The fracture is a ductile dimple fracture without any fatigue lines.

Circumferential and axial microcuts were prepared in the vicinity of the fracture #1 and in the area of the cracked reinforcement. The microstructure evaluation was carried out acc. to DIN EN ISO 945-1: The form of graphite is VI (spherical graphite) with a size of 7 which is a good value. The microstructure is ferrite with spherical graphite and pearlite in some places. The surface beneath the coating (paint) is un-even due to the manufacturing process of the housing and is counted as a normal appearance. All microcuts show the same microstructure.


According to the DIN EN 1563, the hardness should be at least 145 HBW2.5/187.5 at a tensile strength of 400 N/mm. The measured hardness of the housing is 151 HBW2.5/187.5 and is in correspondence to the tensile strength of approximately420 N/mm, see the following chart:

A tensile stress test of the material cast iron (spherical graphite) DIN EN 1563 EN-GJS-400-18LT (GGG40.3/0.7043) was carried out. Three segments were cut out from the housing, 5 samples were prepared with a d0 of 6.05 mm.

Position of the tensile samples (approx.) Three segments were cut out, 5 tensile test samples were prepared.

Sample # RP0.2 [MPa ] Rm A5 [%] 1 283 430 23,7 2 286 435 22,4 3 277 419 24,7 4 277 420 25,2 5 276 419 23,6 Average 280 425 23,9Target acc. to DIN EN 1563 240 400 18,0Measurements of supplier 283 420 22,0

The tensile test results are in accordance with DIN EN 1563. In addition, the results are congruent with values of the supplier AWS.


2.3 Shock Absorber Investigation

The V-sided damper was already disassembled by the customer at delivery. Therefore the functioning could only be inspected of the H-sided damper produced by the company Gimon, Typ 777204, no. 000461. The characteristic curve was measured on the function test bench AN57 and was compared to the characteristic curve which was provided by the customer.

The shock absorber is defined as functional when the damper force is between 884 N and 1196 by both tensile and compression load and a speed of 0.1 m/s. The checking length should reach 50 mm in both directions.

Damper on the function test bench AN57

The results of the function test showed the determined characteristic curve of the H-sided damper matches together with the customers curve. However, the damper force is too high in tensional direction, the value is out of tolerance.

- Value of the force in compression direction: 955 N- Value of the force in tensile direction: 1325 N (too high, max. allowed: 1196 N).

Force-time-diagram: Comparable to the curve provided by the customer


Force-speed-diagram

3. Assessment

The visual inspections of the bearings revealed slight contamination due to debris. Obviously particles were able to intrude into the bearings and were over-rolled. Some particles got caught between cage and rollers which caused the found score marks on the outer ring and roller raceways. The found indentations in a lined formation in the outer ring racetrack of bearing 1 - belonging to the broken case - are quite unusual and may be caused by a singular radial load impact. The amount of particle indentations however is not alarming, yet the origin should be determined on site as impurities reduce the lifetimes of bearings in the long run. Indications of strong shock loads, overloading or tilting were not found. There is strong fretting corrosion on both outer rings which indicates micro movements between the fitted parts. By judging the allocation, we noticed the fretting corrosion in each case to be more distinct towards one row of the double cup. This indicates seating conditions were not ideal respectively the outer rings were not supported evenly over the entire ring width.

All returned case parts showed corrosion characteristics. This most likely is caused by moist weather conditions during service. The housing case part no. 03.024.B is broken in the areas of the mounting suspension. Also, there is a crack on the rein-forcement. The reason for the fractures and the crack cannot be explained by judging the case visually. In general, the visual inspection is only one component of the whole investigation finding out the root cause of the damage.

Therefore further, detailed material analyses were carried out. We found the micro-structure corresponds to the common microstructure of ductile iron EN-GJS-400-18LT. Also, the hardness is within the specification. The housing was ordered according to the DIN EN 1563. There is no definition of the microstructure; howeverthe material properties such as tensile stresses, elongation, etc. are defined. To evaluate these parameters a tensile stress test was carried out. The values of RP0.2, Rm and A5 were all within the specification.

The damper test results showed the force in tensile direction was too high. Unfortu-nately we do not know if the forces of the V-sided damper were in tolerance as it al-ready was disassembled by the customer at delivery. The test results of this damper perhaps would have revealed more information about the root cause of the damaged case base.


The initial fractures seem to start from the outer diameter of the housing (fractured area 1 in Fig. 36, shock absorber side) and was initiated due to fatigue. The exact reason for the case breakage must be determined on site, as the material inspection results were in specification and also the bearings are in an overall good condition.

Remark: The screws were mounted in the correct positions. However, when mounting the screws the higher tightening torque amount of the fitting screw (260 Nm instead 130 Nm for the remaining 7 screws) has to be carefully attended to.

There are no signs of manufacturing defects or faults in workmanship.

As requested, we will send the parts back to the final customer DSB Fjern & Re-gionaltog, attn. to Mr. Jan Elgaard.

Schaeffler Technologies GmbH & Co. KGDamage Analysis

i. A. Anderson i. A. Betz

Enclosure: 88 pictures

cc: Mr. Scheck IEISWE-RARMs. Neeb SI/SWE-QMVMr. Reese Schaeffler Denmark


Fig. 1FAG TAROL 150/250-USA-B-04.93404 (Bearing 1): Condition at delivery

Fig. 2Bearing 1, condition at delivery

Fig. 3Bearing disassembled and cleaned, outer ring: Strong fretting corrosion on the outside diameter


Fig. 4Bearing 1, outer ring racetracks:

Isolated particle indentations (left racetrack)

Slight circumferential scores (right racetrack)

Fig. 5Isolated particle indentationsThe two lines indicate a lined formation of indentations in axial direction

Fig. 6Detail of the single particle indentation of Fig. 5


Fig. 7Particle indentation in the outer ring racetrack of bearing 1

Fig. 8Several circumferential scores in the outer ring racetrack (right racetrack of Fig. 4)

Fig. 9Inner ring, cage and roller assemblyIsolated indentations on the inner racetrack


Fig. 10Inner ring, cage and roller assemblyIsolated indentation on the inner racetrack

Fig. 11Detail of Fig. 10

Fig. 12Seating marks in the inner ring bore


Fig. 13Cage of bearing 1:Normal contact marks in the pockets

Fig. 14Inner ring, cage and roller assembly: Light contact marks on the inner ring side face

Fig. 15Rollers of bearing 1:Circumferential, feelable score marks on the raceways


Fig. 16Rollers of bearing 1:Contact marks on the side faces

Fig. 17Sealing caps of bearing 1

Fig. 18Corrosion characteristics cover the backing ring of bearing 1


Fig. 19Contact marks on the outside diameter of the spacer ring

Fig. 20Light contact marks in the inner diameter as well as on the faces of the spacer ring

Fig. 21FAG TAROL 150/250-USA-B-04-93962 (Bearing 2):Condition at delivery


Fig. 22Bearing 2, outer ring:Local fretting corrosion on the outside diameter

Fig. 23Outer ring racetracks of bearing 2: Isolated particle indentation, light score mark

Fig. 24Outer ring racetrack of bearing 2: Light score marks


Fig. 25Outer ring racetrack of bearing 2: Isolated particle indentation, pressure mark

Fig. 26Inner ring, roller and cage assembly of bearing 2

Fig. 27Inner ring of bearing 2:Seating marks in circum-ferential and axial direction


Fig. 28Rollers of bearing 2:Circumferential score marks on the running areas, contact marks on the side faces

Fig. 29Components of bearing 2 are normal in apearance

Fig. 30Sealing caps of bearing 2


Fig. 31Corrosion characteristics on thebacking ring

Fig. 32Case parts, condition at delivery

Fig. 33Housing base, overview


Fig. 34Broken housing base 5618 VS, condition at delivery:There is a beginning crack in the reinforcement indicated withthe red ellipse

Fig. 35Case no. 03.024.B

Fig. 36Housing base 03.024.B, overview of the broken areas:The fractures are close to the mounting suspension areas1

2


Fig. 37Broken housing base side 1

Fig. 38Broken housing base side 2


Fig. 39Fracture #1, overview picture:

Appears as a primary fracture,because surface is smearedAn axial and two circumferential microcuts were prepared

Fig. 40Fracture #1, location of the circumferential microcut U2

Fig. 41Fracture #1, detail of Fig. 39:The initial crack starts from the outer diameter of the housing as a fatigue fracture nodeformation/necking

Fig. 42Fracture #1, opposite side:

Circumferential microcut U1


Fig. 43Fracture #1, SEM investigation

Fig. 44Fracture #1, SEM investigation:

The fracture area is smeared, so that the surface is deformed

Fig. 45Fracture #1, SEM investigation:

In some places there are hints for a fatigue fracture visible

fatigue lines in the area ofthe grain boundaries


Fig. 46Laboratory fracture, SEM investigation:

One piece of the housing near fracture #1 was cut out and broken in a press laboratory fracture

The fracture is a ductile dimple fracture (no fatigue fracture indications visible)

Fig. 47Laboratory fracture, SEM investigation:

Detail of Fig. 46.

Fig. 48Circumferential microcut U2:

Microstructure evaluation according toDIN EN ISO 945-1

Form: VI spherical graphiteSize: 7


Fig. 49Microcut in the vicinity of the cracked bar: The edge shows a pearlite layerin some places (due to the manufacturing process)

Position of the microcut:


The initial crack starts from the outer diameter of the housing as a fatigue fracture nodeformation/necking


The initial crack starts from the outer diameter of the housing as a fatigue fracture nodeformation/necking


Fig. 52Housing base (the other side of the damaged base part) covered with crack detection substance

Fig. 53No crack detected on the reinforcement

Fig. 54No cracks detected in the areasof the mounting suspensions


Fig. 55Corrosion characteristics in the inside diameter of the housing base

Fig. 56No cracks detected in the areas of the mounting suspension

Fig. 57Housing upper components:Strong fretting corrosion in the seats of the TAROL-housing parts


Fig. 58Detail of Fig. 57, front part

Fig. 59Detail of Fig. 57, back part

Fig. 60TAROL-Housing (front part):Strong corrosion characteristics in the outside diameter


Fig. 61Bearing seating area of the housing part of Fig. 60:Axial and circumferential seating marks as well as fretting corrosion characteristics

Fig. 62TAROL-Housing (back part):Strong corrosion characteristics on the outside diameter

Fig. 63Bearing seating area of the housing part of Fig. 62:Fretting corrosion characteristics


Fig. 64Dampers V side and H sideThe V-sided damper had been opened by the customer

Fig. 65Damper V side:Specification

Fig. 66Damper V side, expanded


Fig. 67Damper V side:Score mark on the damper

Fig. 68Piston rod of damper V side:Pressure polished area located approximately in the centre

Fig. 69Damper H side, expanded:Scored locally



Fig. 71Covers, outside

Fig. 72Covers, inside:Corrosion characteristics on the edge


Fig. 73Sealing rings

Fig. 74Gear wheel

Fig. 75Black dust-like material in the inside surface of the gear wheel


Fig. 76Screws, bolts, nuts and shims

Fig. 77Several screws corroded

Fig. 78Screws


Fig. 79Bolts, nuts and shims

Fig. 80Returned o-ring seal:Damaged in one area



Fig. 82Housing base 5618 VS (fractured side), position d of the drawing on page 3 (fitting screw M20x110 DIN 609)

Fig. 83Housing base 5618 VS, position c of the drawing on page 3 (screw M16x110 ISO 4014)

Fig. 84Housing base 5618 VS, positions a and b of the drawing on page 3 (screws M16x110 ISO 4014)


Fig. 85Overview of the housing bases

Broken housing base

Fig. 86Broken housing base, close view:Characteristic corrosion spot

Fig. 87Journal bearing housing: Characteristic corrosion spot


Fig. 88Bearing 1 matches to the journal bearing housing of the broken case

schaeffler technology rapport om skader på ic4 aksellejekasser, 28. marts 2011

Documents

fag tarol

inner rings

visual inspection2 tarol

spacer rings

outer rings

isolated indentations

isolated particle indentations

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