1、看nd鋼管的表麵。觀察亮度和（hé）表麵有無漏焊和（hé）脫皮等表麵問題。好的nd鋼管表麵色澤光（guāng）亮，一般情況下不會（huì）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（zhì）。nd鋼管化學成分是的基礎。檢查化學成分是否達標是nd鋼管很（hěn）重要的檢（jiǎn）查方式。還有（yǒu）就是檢查是否精煉爐（lú）的材料。
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（yuán）管的圓（yuán）度、方管的（de）方度、表麵的處理、nd鋼管兩端的處理、還有（yǒu）很重要的一點（diǎn）就是整隻鋼管的平直度。
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鋼管廠家擁有好的管理層、好的操作（zuò）工、好（hǎo）的製（zhì）度、有一（yī）定的知名度和信譽度，產出來的產品自然也能滿足客戶的高端要求。而一些小的或者不正（zhèng）規的鋼管（guǎn）廠（chǎng）家（jiā）生產出來nd鋼管不僅在外觀上與好的nd鋼管有差距，其堅硬程度、韌性，也有很大的差距。
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.
