合金A335P92全称

A335-P91 (9Cr-1Mo and V+Nb+N)

there are a few more differences in a P-91 and a P-92. The main thing being Tungsten, which is used for added high temperature properties over the "modified" 9Cr grades (P-91). P-91 contains no tungsten

In this P92, tungsten plays a mojor part in improving creep strength values, so it is odd it is not given more credit. Comparing the P91 to the P92, there are various min/max rangers concerning the carbon, Si, P, Cr, Mo (which yu pointed out), W ( a big difference here), Ni, V, Nb, Al, and B ( which we idscussed). The differences are slight except for the tungsten.

参考资料
http://ww.aws.org/cgi-bin/mwf/topic_show.pl?tid=6917
American Welding Society Online Forum