Round robin of trace elements

Abstract

A round robin of measurement of trace elements P, As, Sb, Sn, Pb, and Bi in 2 1/4 Cr–1 Mo–V steel has been conducted in IIW Commission II. Samples of three heats were distributed among seventeen laboratories. Results were used to calculate the Bruscato and Watanabe factors for temper embrittlement resistance, which factors are used commercially to accept or reject matching steel filler metals for elevated temperature service. Likewise, results were used to calculate a reheat cracking factor proposed for acceptance or rejection of heats of matching steel filler metals to resist reheat cracking during extended postweld heat treatment. The results obtained show quite acceptable reproducibility of measurement of elements comprising the Bruscato and Watanabe factors in which statistically significant differences among the heats could be found. But the results obtained show very poor reproducibility of measurement of Pb and Bi so that statistically significant differences in the calculated reheat cracking composition factor could not be found among the heats unless the analytical method was restricted to ICP-MS.