1、看nd鋼管的表麵。觀察亮度和表麵有無漏焊（hàn）和脫皮等表麵問題。好的（de）nd鋼管表麵色（sè）澤光亮，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（cái）質。nd鋼（gāng）管化學成分是的基礎。檢查化學成分是否達標是nd鋼管很重要的檢查方式。還（hái）有就是檢查（chá）是否精煉（liàn）爐的材（cái）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（kàn）做工。圓管的圓度（dù）、方管的方度、表麵（miàn）的處理、nd鋼管兩端的處理、還有很重要（yào）的一點就是整隻鋼管的平（píng）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（jiā）擁有好的管理層、好的操作工、好的製度、有一定（dìng）的知名度和信（xìn）譽度，產出來的產品（pǐn）自然也能滿足客戶的高端（duān）要（yào）求。而一些小的或者不正規的鋼管廠家生產出來nd鋼管不僅在外（wài）觀（guān）上與好的nd鋼（gāng）管有（yǒu）差（chà）距，其堅硬程度、韌性，也有很大的差距（jù）。
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.
