DIN 25201-4 - Nord-Lock
DIN 25201-4 - Nord-Lock DIN 25201-4 - Nord-Lock
DIN 25201-4 "Reliability of bolted joints with locking elements for railway vehicle applications" The securing characteristics of bolted joints have a relevant affect on the operation availability of railway vehicles. Nevertheless they are still a significant problem for railway vehicle OEMs and rail operators today, because many commonly used bolt-securing elements emerged to be ineffective. Therefore, a comprehensive research, financed by the rail industry, was done between October 2004 and December 2006. The aim was to systematically investigate the parameters that influence the loosening of bolts, and to develop a detailed norm procedure in order to evaluate the performance of securing elements. The initiators of this research were Alstom LHB Salzgitter, Bombardier Transportation Henningsdorf, Siemens Transportation Systems Krefeld, Deutsche Bahn Systemtechnik and three OEMs of securing elements including Nord-Lock GmbH, who were preselected by above-mentioned companies. The washers of Nord-Lock were the only tested securing elements based on wedge-locking function. The analyses have been done by “IMA Materialforschung & Anwendungstechnik GmbH” in Dresden and by the Institute for product development and design engineering of the University of Applied Science in Cologne. The influence of the eight parameters on the self-loosening of a bolted joint was systemically investigated through specific parameter studies, which were determined by means of test rigs. International Sales Office & Technical Verification Center NORD-LOCK International AB Tel +46 31 71 92 300 Rådmansgatan 10, 3tr Fax +46 40 240 851 211 46 Malmö, Sweden info@nord-lock.com VAT No. SE556610573901 www.nord-lock.com
<strong>DIN</strong> <strong>25201</strong>-4<br />
"Reliability of bolted joints with locking elements<br />
for railway vehicle applications"<br />
The securing characteristics of bolted joints have a relevant affect on the operation<br />
availability of railway vehicles. Nevertheless they are still a significant problem for railway<br />
vehicle OEMs and rail operators today, because many commonly used bolt-securing<br />
elements emerged to be ineffective.<br />
Therefore, a comprehensive research, financed by the rail industry, was done between<br />
October 2004 and December 2006. The aim was to systematically investigate the<br />
parameters that influence the loosening of bolts, and to develop a detailed norm procedure<br />
in order to evaluate the performance of securing elements.<br />
The initiators of this research were Alstom LHB Salzgitter, Bombardier Transportation<br />
Henningsdorf, Siemens Transportation Systems Krefeld, Deutsche Bahn Systemtechnik<br />
and three OEMs of securing elements including <strong>Nord</strong>-<strong>Lock</strong> GmbH, who were preselected<br />
by above-mentioned companies. The washers of <strong>Nord</strong>-<strong>Lock</strong> were the only tested securing<br />
elements based on wedge-locking function.<br />
The analyses have been done by “IMA Materialforschung & Anwendungstechnik GmbH” in<br />
Dresden and by the Institute for product development and design engineering of the<br />
University of Applied Science in Cologne.<br />
The influence of the eight parameters on the self-loosening of a bolted joint was<br />
systemically investigated through specific parameter studies, which were determined by<br />
means of test rigs.<br />
International Sales Office & Technical Verification Center<br />
NORD-LOCK International AB Tel +46 31 71 92 300<br />
Rådmansgatan 10, 3tr Fax +46 40 240 851<br />
211 46 Malmö, Sweden info@nord-lock.com<br />
VAT No. SE556610573901 www.nord-lock.com
1. Thread size<br />
2. Quality<br />
3. Clamp length ratio<br />
4. Preload<br />
5. Amplitude<br />
6. Lubrication<br />
7. Surface quality of bolt / nut<br />
8. Test frequency<br />
Based on the test results, failure criteria were identified. For the design engineering of<br />
railway vehicle OEMs and suppliers, these criteria provide a decision-making basis in<br />
order to determine the proper locking elements.<br />
By means of the assessment criteria according to <strong>DIN</strong> <strong>25201</strong>-4, the overall assessment<br />
result is as follows:<br />
All <strong>Nord</strong>-<strong>Lock</strong> wedge-locking washers (without any exception) which were tested<br />
according to <strong>DIN</strong> <strong>25201</strong>-4:2010-01(E) Appendix B, have had a remaining clamping<br />
load of more than 80% after 2.000 cycles. The <strong>DIN</strong> Norm Committee released this<br />
Appendix B of the <strong>DIN</strong> <strong>25201</strong>-4 in November 2010 for white print.<br />
Based on this quantitative test result, the securing characteristics of the tested <strong>Nord</strong>-<strong>Lock</strong><br />
cam washers are proven to be fully effective and are compliant to the test procedure<br />
according to Appendix B of the <strong>DIN</strong> <strong>25201</strong>-4.<br />
A work team of the initiating companies has accompanied the project and reviewed the<br />
research results regarding their pertinence for the joining technology and implementation<br />
into the <strong>DIN</strong> <strong>25201</strong>-4. The period for formal objections regarding the draft of the <strong>DIN</strong><br />
<strong>25201</strong>-4 ended on September 30th, 2010. The official release by the <strong>DIN</strong> Norm Committee<br />
is imminent.<br />
International Sales Office & Technical Verification Center<br />
NORD-LOCK International AB Tel +46 31 71 92 300<br />
Rådmansgatan 10, 3tr Fax +46 40 240 851<br />
211 46 Malmö, Sweden info@nord-lock.com<br />
VAT No. SE556610573901 www.nord-lock.com
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