1、看nd鋼（gāng）管的表麵（miàn）。觀察亮度和表麵有無漏焊和脫皮等表麵問題。好的nd鋼管表麵色澤光亮，一般情況下不會生鏽。
1. Look at the surface of ND steel pipe. Observe the brightness and surface problems such as welding leakage and peeling. A good ND steel pipe has a bright surface and will not rust in general.
2、看材質。nd鋼管（guǎn）化學成分是的基礎。檢查（chá）化學成分是否達標是nd鋼管很重要的檢查方式。還有就是檢查是否精煉爐的（de）材料。
2. Look at the material. The chemical composition of ND steel pipe is the basis. Checking whether the chemical composition is up to the standard is an important inspection method for ND steel pipes. The other is to check whether the material of the refining furnace is available.
3、看做工。圓管的圓度、方管的方度、表麵的處理、nd鋼管兩端的處（chù）理、還有很重要的一點就是整隻鋼管（guǎn）的平直度。
3. Look at the workmanship. Roundness of circular pipe, squareness of square pipe, surface treatment, treatment of both ends of ND steel pipe, and a very important point is the flatness of the whole steel pipe.
4、好的nd鋼管廠家擁有好（hǎo）的管理層、好的操作工、好（hǎo）的製（zhì）度、有一定的（de）知名度（dù）和信譽度，產出來的產品自然也能滿足客（kè）戶的高端（duān）要求。而一些小的（de）或者不正規的鋼管廠家生產出來nd鋼管不僅在外觀上與（yǔ）好的nd鋼管有差距，其堅硬程（chéng）度、韌性，也有很大的差（chà）距。
4. Good ND steel pipe manufacturers have good management, good operators, good system, a certain degree of popularity and credibility, and the products can naturally meet the high-end requirements of customers. And some small or irregular steel pipe manufacturers produced ND steel pipe not only in appearance and good ND steel pipe has a gap, its hardness, toughness, but also a big gap.
