幫你查了一下原標準文件 ASTM A179 和 SA179 標準的鋼管材料的硬度是 ≤ 72HRB。
原標準文章中是這樣講的：
10. Hardness Requirements：10.1 The tubes shall have a hardness number not exceeding 72 HRB.
10．硬度要求：10.1 鋼管的硬度系數不得超過 72 HRB.
11.4 Hardness Test—Rockwell hardness tests shall be made on specimens from two tubes from each lot. The term lot applies to all tubes, prior to cutting, of the same nominal diameter and wall thickness which are produced from the same heat of steel. When final heat treatment is in a batch-type furnace, a lot shall include only those tubes of the same size and the same heat which are heat treated in the same furnace charge. When the final heat treatment is in a continuous furnace, a lot shall include all tubes of the same size and heat, heat treated in the same furnace at the same temperature, time at heat, and furnace speed.
11.4 硬度測試：從每批（注意事項2）中抽取2 支鋼管進行洛氏硬度測試。“一批”應包括所有的，在切頭尾前，同一熱處理和同批鋼坯生產的，有相同的名義直徑和壁厚的鋼管。在同一型號的同一熱處理爐中進行最后的熱處理時，“一批”應指所有在同一爐中進行熱處理的同尺寸的鋼管。當最后熱處理在連續(xù)式熱處理爐中進行時，“一批”應包括所有的同尺寸，熱度，在同一爐中同樣溫度，時間，速度進行熱處理的鋼管。