首先要看nd钢管的表面。观察亮度和表面有无漏焊和脱皮等表面问题。好的nd钢管表面色泽光亮，一般情况下不会生锈。 第二点就是看材质。化学成分是nd钢管的基础。检查化学成分是否达标是nd钢管很重要的检查方式。还有就是检查是否精炼炉的材料。 第三点就是要看做工。圆管的圆度、方管的方度、表面的处理、nd钢管两端的处理、还有很重要的一点就是整只钢管的平直度。
First of all, we should 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. The second point is to look at the material. Chemical composition is the basis of ND steel pipe. 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. The third point is to 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.
最后，好的nd钢管厂家拥有好的管理层、好的操作工、好的制度、有一定的知名度和信誉度，产出来的产品自然也能满足客户的高端要求。而一些小的或者不正规的钢管厂家生产出来nd钢管不仅在外观上与好的nd钢管有差距，其坚硬程度、韧性，也有很大的差距。
Finally, a good ND steel pipe manufacturer has good management, good operators, good system, a certain degree of popularity and credibility, and the products produced 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.
nd钢管良好的温度控制试管冶金过程的顺利完成，如氧化脱磷的保证不仅要求高，高碱度渣，还需要具有良好的耐高温配合。这是强调理性的早期脱磷。因为这时温度低有利于关盘;在氧化精炼期间，造成活性炭氧沸腾，要求具有高温（大于1550?）;冶金工程使炉侯处理和周围浇铸正常为，根据使用的不同的过程中，要求炉早钢液具有过热度的必须的，以补偿出钢过程中，与炉输送，处理的精炼和钢液外温度的损失。
The smooth completion of the metallurgical process of ND steel tube with good temperature control, such as the guarantee of oxidative dephosphorization, requires not only high requirements, high basicity slag, but also good high temperature resistance cooperation. This is to emphasize rational early dephosphorization. Because the low temperature is beneficial to shut down at this time; during the oxidation refining period, the activated carbon oxygen boiling is caused, requiring a high temperature (greater than 1550); metallurgical engineering makes the furnace processing and surrounding casting normal; according to the different process used, it is necessary to require the furnace early molten steel to have superheat, in order to compensate for the loss of refining and molten steel temperature in the process of tapping, conveying with the furnace, processing.
