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1 KSKSKSKS KSKSKSK KSKSKS KSKSK KSKS KSK KS KS R 9221 Wheels for railway rolling stock KS R 9221:2008 Translated and Published by Korean Standards Association Translation without guarantee In the event of any doubt arising, the original standard in korean is to be evidence www. kssn.net C KSA 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher

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3 KOREAN INDUSTRIAL STANDARD KS R 9221:2008 Wheels for railway rolling stock 1 Scope This Korean standard specifies carbon steel rolled wheels (hereinafter, referred to as wheels) used for railway rolling stock with the maximum speed of below 150 km/h. 2 Normative References The following referenced documents contain provision which, through reference in this text, constitute provisions of this standard. These normative references apply the latest version. KS B 0801, Test pieces for tensile test for metallic materials KS B 0802, Method of tensile test for metallic materials KS B 0805, Method of brinell hardness test KS B 0809, Impact test pieces for metallic materials KS B 0810, Method of impact test for metallic materials KS B 0817, General rule of ultrasonic testing of metals by the pulse echo technique KS D 1801, General rules for chemical analysis of iron and steel KS D 1802, Methods for determination of phosphorus and iron and steel KS D 1803, Methods for determination of sulfur in iron and steel KS D 1804, Determination of carbon in iron and steel KS D 1805, Determination of silicon in iron and steel KS D 1806, Methods for determination of manganese in iron and steel 3 Terms and definition For the purposes of this document, the following terms and definitions apply. 3.1 Wheel contact surface abrasion areas of a cylinder part of wheels which come in contact with railways

4 3.2 Rim edge portion of wheels including the surface which comes in contact with railways 3.3 Boss part of wheels where axles are pressured 3.4 Plate circular plate which connects the rim with the boss 4 Types As shown in Table 1, type of wheels is categorized by use. Table 1 Types of wheels Symbol Use Note RSW1 Rolling stock Quenching or tempering for rim RSW2 Electric locomotive or electric rail car Quenching or tempering for rim RSW3 Diesel locomotive or diesel rail car Quenching or tempering for rim 5 Requirements a) Wheels must be consistent in quality, and there must be no marks, scratches, exfoliation, pulling and other defects under a normal condition. b) Wheels are manufactured by steel which is dissolved by using Basic oxygen furnace, Open-hearth furnace or Electric furnace. Deacidification process is performed on the steel in the furnace and ladle and the steel is made by casting method or continuous casting method. When the casting method is used, it should be made by lower casting. c) Wheels are forged and then formed by rolling. The rim part must be heat-treated i.e. quenching or tempering. d) Wheel shapes (Figure 1) follow an authorized manufacturing drawing. Unless there is mutual agreement between parties concerned, wheel shapes must meet the rules suggested by the below Tables 2 and 3. If there are sectional marks on plate parts as well as around the section R of the boss, the depth must be within 10 percent of the cylinder thickness. 2

5 Figure 1 Shapes of a wheel Classification Wheels Without with process With for section R Wheels Without without process With for section R Table 2 Allowable values of dimensions unit: mm Allowable values of dimensions Plate Rim thickness thickness t 1, t 2 T +6 3 or 0 below +6 3 or 0 below +8 3 or 0 below +6 3 or 0 below Inner diameter of Rim d Outer diameter of Boss D 1, D Boss thickness T 1, T 2 10 or below 10 or below 10 or below 10 or below Inner diameter of Boss d -4-6 Height of plate parts l Central distance of cross section of Plate E ±6.5 ±3 - ±6.5 ± ±8.5 ±5 - ±8.5 ±5 3

6 Table 3 Allowable values of dimensions for rim Allowable values of dimensions Classification Location of rim Outer diameter of rim C K D Without process With process +0-2 unit: mm 6 Inspection and test methods 6.1 Types of inspection and methods The whole manufactured products are tested by the following items and determined when must pass each test. a) Appearance inspection In accordance with an authorized manufacturing drawing, there must be no marks, polluted damage, exfoliation and other defects found through inspectors eyes. b) Dimension inspection Dimensions of each part must be inspected to check if they are consistent with the manufacturing drawing. 6.2 Types of inspections and methods a) Ultrasonic test is done for the whole manufacture product, whereas a chemical analysis test, tensile strength, hardness or impact test is done in type checking. b) For the chemical analysis test or mechanical quality test, one wheel from each steel furnace is chosen from which test pieces are extracted. If all test pieces are considered fine, respective steel products can be used Chemical analysis test Chemical analysis test of wheels are presented in Table 4 in accordance with KS D 1801, KS D 1802, KS D 1803, KS D 1804, KS D 1805, KS D

7 Table 4 chemical compositions of wheels unit :% composition C Mn Si P S Cu Content 0.67 or below 0.6 ~ or above or below or below 0.35 or below Test for mechanical qualities a) Tensile strength, hardness, impact test pieces are extracted from the rim part of wheels. With hardness test pieces being in a cross section form as shown in Figure 2, hardness of each wheel must be above the minimum values at the depth of 25 mm from the wheel contact point. Hardness test is based on KS B 0805, while tensile strength or impact test pieces are extracted from the marked areas shown in Figure 3 and 4. unit: mm Figure 2 Hardness test piece unit: mm Figure 3 Location of extracting tensile strength test piece 5

8 unit: mm Figure 4 Location of extracting impact test piece b) The sample of KS B 0801 Issue 4 is used for tensile strength test of wheels in accordance with KS B c) The sample of a) U notch in Figure 2 of KS B 0809 is tested three times in accordance with KS B d) Mechanical qualities of wheels must be within the figures of the below Table 5. The minimum limits of strain and cross-section contraction rate are the lower limit of tensile strength and the upper limit of tensile strength respectively. Strain or cross-section contraction rate for the midrange tensile strength is calculated through a rule-of -three sum. Table 5 Mechanical qualities by type of wheels Tensile strength test Symbol Tensile Cross-section Strain strength contraction rate (%) (N/mm 2 ) (%) RSW1 835~ (min) 28 (min) 11 (min) 23 (min) RSW2 930~ (min) 26 (min) 10 (min) 20 (min) RSW3 980~ (min) 22 (min) 8 (min) 16 (min) Hardness test Charpy impact test Absorption Hardness energy (HB) (J) 248~ or above 269~ or above 294~ or above 6

9 6.2.3 Ultrasonic test Ultrasonic tester must have a frequency range of 2 to 5MHz. In accordance with KS B 0817, the inspection is done after heat-treatment to check if there are internal discontinuous structures of all rim parts of wheels. There must not be echoes due to internal defects. 6.3 Retest Although there are some faulty mechanical qualities found, a retest can be done by using extracted two blank materials. If one of the two fails to meet the standards again, the whole product in the steel furnace can be annealed and re-heat treated for one more test. However, in this case, tensile strength, hardness and mechanical qualities test are done for two wheels. 7 Marking and packaging 7.1 Marking The following contents must be stamped in an easily-noticed place. The method of stamping (cold or hot) and its location are subject to the agreement between parties concerned. a) Manufacturing date (month / year) b) Name of manufacturer c) Number of steel furnace 7.2 Packaging Finished products must be suited for transportation and storing. -end- 7

10 KSKSKS SKSKS KSKS SKS KS SKS KSKS SKSKS KSKSKS Wheels for railway rolling stock ICS Korean Standards Association