耐熱 たいねつ合金 ごうきんではありませんでした
tainetsugōkindewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 耐熱合金

1. Was not a heat-resistant alloy.; Was not a high-temperature alloy.

Past/Perfective
Negative
Polite
Formal Register