NB/T 47021  法兰 RF 800-1.0 ذ²ز–“ذ،ز،ذ’آ¬ذ’آ©ذ²ز–“ذ ذژذ ذ†ذ ز³ذ سکذ ذ†ذ ز°ذ ذˆذ²ز–“ذ،ز،ذ ذ†ذ ز°ذ ر‍ذ²ز–“ذ ذژذ ذ†ذ