Creep Crack Growth(CCG) is a failure mechanism which is resulting in catastrophic failure in pressure parts in a wide variety of carbon manganese steels made to various national and international specifications and operating in the range 300-420 c.Such failures are both expensive and place at risk the lives of operating personnel. Work on testing of such failures from accross Europe has indicated that the CCG properties of carbon manganese steels depend critically on their minor or residual element content as affected by deoxidation practice(eg free nitrogen) and the cold working to which they have been subjected.These failures are not specified in European or other steel standards at the present time.In addition experience has shown that susceptible-to-failure steels become more vulnerable in older utilities thus necessitating the need for development of methodologies for estimating safe operating life of such utilities.
This proposal plans to test three purpose produced steels of high, medium and low free nitrogen levels for their creep and creep crack growth characteristics.Similar tests are also planned on commercially produced pipe and tube steels.From these tests and tests on pipe and tube components it is to planned :
a) recommend new specifications for European standards for such steels, and
b) develop methodologies for remanent life assessment of in-service components.
Funding SchemeCSC - Cost-sharing contracts
7522 LR Enschede