When Is T41 Not T41, Or Durehete 1055™ Equivalent?
Quite a few of our customers have asked us for advice when they have been offered “T41” at a “cheap” price. They quite rightly have checked with the experts that the material they have been offered is fit for their purpose.
Both BMG-AT41® and Durehete 1055™ are based on standard product such as BS EN 10269 1999, Werkstoffe 1.7729 and the chemical equivalent 20CrMoVTiB4-10, however both are trade marked products because they are not just “bog-standard”.
The basic material does just not come anywhere near the specifications called for in many coal fired power stations for which the material is intended. Just a very quick glance at one mill cert for “1.7729” that we have been asked to look at recently threw up the major differences between BMG-AT41® and the base product:
- Lack of clarity on means of production. Product destined for power applications should be clearly produced by an ingot route.
- Lack of a clearly identified and approved production route detailing all the aspects of the production route and parameters.
- No confirmation of the maximum individual grain size, not just an average apparent grain size according to ASTM E112. The latter should really be carried out at an independent test house because the quality of the micrographs is superior to that produced by mills – the photo in the cert we were asked to check had very poor definition and had no basic information of the etchant used.
The old adage “you get what you pay for” is never more true. Unfortunately the total cost of using base material instead of the right material could be very costly.