Wheelsets & bogies


Table 1 Properties


Rim MYS0.2


[MPa]


UTS [MPa] A [%] Z [%] KCU KV KV


Position a, b, c [J] (-20°C [J] (-40°C) [J]


K Gost (-60°C) [J] KQ


room temperature MPa√m


860-980 ≥ 14 ≥ 40


≥ 17 (12) ≥ 10 (7) ≥ 10 (5) ≥ 70 (60) ≥ 70 (60)


Hardness in the section [HB] Position B at 35mm ≥ 245 Hardness in the section [HB] PositionC≤300 Hardness in the section [HB] PositionA∆(B-A) >10


Web MYS0.2


Z [%]


in a ladle furnace and a vacuum degassing plant. The acceptable limits of the various elements and residuals initially appear very similar to the acceptability limits of ER8 steel grade, but the difference is in the balancing of the chemical elements. The verification of an analysis is also


usually carried out by cast analysis, realised on specimens taken after vacuum degassing, and before pouring. Astandard test piece has a diameter


of 10mm and a length of 50mm. The mechanical properties of test pieces taken from the web of the wheels are checked to ensure that the web has not been affected by the heat treatment of the tread (rim chilling). Six pieces are tested at -20oC. These characteristics usually need to


be verified on tread-braked wheels. In any case Lucchini RS performs such tests on the entire production of solid wheels to avoid brittle fractures and to guarantee safety in service. To correlate other quality indicators


with low temperature during service, additional tests are conducted on one wheel per batch, namely a three-impact K Gost test at -60oC in the rim and a three-impact K Gost test at -60oC in the web. ABrinell hardness test on the rim is


Geatech at: NORDIC RAIL 2013


Jönköping, Sweden Stand No. B04:109


8th-10th October 2013 www.geatech.it


40


also undertaken to check the uniformity of batches. The position of the indent is prepared in accordance with the requirements of European standards. The measurement of the Brinell hardness (10mm diameter ball) is checked on the rim of each wheel, after heat treatment. The extreme hardness values of the rims of wheels from the same batch must not exceed 30HB in order to guarantee a good homogeneity of the batch.


[MPa]


UTS [MPa] A [%]


≥ 400


∆≥ 120 ≤ 820 ≥ 16 ≥ 40


K Gost (-60°C)J≥70 (60) Arcticlos


Requirements Obtained values ≥ 540


600 950 17 45 22 16 12


100 85


255 290 220


450 140 750 22 45


110 The hardness readings are carried out


on a radial section of the rim and its transition to the web, taken from the sample segment designated for this purpose. The test must be performed in accordance with EN ISO 6506-1. The ball diameter is 5mm and the test is the usual HB5/750/15, with seven hardness readings carried out on the


polished face of the test piece:  three readings at 5mm below the


tread surface of the new wheel  three readings at a depth of 35mm from the tread surface of the new


wheel, and  one reading at the transition between the rim and the web. Compared with EN standard steel grades, the wear limit is at 35mm. Lucchini RS uses standard test methods to determine the inclusion content of its steel production and performs a rating of non-metallic inclusions of its entire production. The cleanliness of the rim is checked to ensure that it is in accordance with a set of pre-determined values. The microstructure is documented on


the sample in ‘F` position, located at a depth of 15mm from the nominal diameter. The microstructure always consists of a fine lamellar pearlite and ferrite with a pearlitic grain size in accordance with ASTM E112-10 equal or greater than degree 6. Traces of bainitic structures in the rim are acceptable. The first results obtained from the


production of Arcticlos are shown in Table 1, demonstrating that the requirements have been more than fulfilled. As earlier studies have shown, a


good quality index for the mechanical properties of a wheel is the product of


IRJ September 2013


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