美国图纸

zhaodelai321

求助以下字母都是什么意思
3 \0 x' H4 h! a1 A0 [6 z, A. D+ mHDNS BR 2.7~3.0
' N! |) S8 c/ N+ r. g7 ^* A* C! uHDNS AT 20 DP FACE A RKW C40 MIN
9 x; `& ]& M. E% _4 y" l" |FURNACE TEMPER ONLY
7 H# `" T3 z# ?: p+ k8 V3 ROPT HDNS PATTERN
HDNS BR 2.9~3.4
HDNS LG H BR 2.7~3.0
6 U% T8 x+ N; y% `* RHDNS AT 20 DP FACE A RKW C40 MIN