1. Chemical Constituents
对有害化学元素 As Sn Sb Bi Pb 和气体 N H O 等含量提出了请求，为了进步钢中化学成分的平均性和 钢的纯洁度，减少管坯的非金属夹杂物并改善其散布状态，常常采用炉外精炼设备对钢水停止精炼，以至采用电渣炉对管坯停止重熔精炼。
Requests are made for the contents of harmful chemical elements such as As Sn Sb Bi Pb and NH O. In order to improve the homogeneity of chemical composition in steel and the purity of steel, reduce the non-metallic inclusions in tube billet and improve its dispersion, it is often used to stop refining molten steel with out-of-furnace refining equipment, or even to stop refining tube billet with electroslag furnace.
2. Dimensional accuracy and shape
The geometric dimensions of seamless steel pipe mainly include the outer diameter, wall thickness, ellipticity, length, bending, end-face tangential slope, groove angle and blunt edge, cross-sectional dimensions of heterosexual steel pipe, etc.
3. Appearance quality
The requirement of "appearance brightness" of seamless steel pipe is regulated in the code. Common defects are: cracks, hairlines, internal folds, external folds, rolling, internal straight, external straight, delamination, scarring, pits, convex hulls, pits (pockmarks), scratches (scratches), internal spiral, external spiral, blue line, correction concave, roll prints, etc. Among them, cracks, internal folds, external folds, rolling, delamination, scarring, pits, bumps and other risk defects; steel pipe linen, green line, scratches, fine internal and external straight, fine internal and external spirals, concave correction, roll printing are common defects.
4. Physicochemical properties
包括常温下的力学性能和一定温度下的力学性能（热强性能和低温性能）和抗腐蚀性能（如抗氧化、 抗水蚀、抗酸碱等性能）普通状况下取决于钢的化学成分、组织性能和钢的纯洁度以及钢的热处置方 式等。有些状况下，钢管的轧制温度和变形水平也会对钢管的性能产生影响。
The mechanical properties at room temperature and at a certain temperature (thermal strength and low temperature) and corrosion resistance (such as oxidation resistance, water corrosion resistance, acid and alkali resistance) depend on the chemical composition, structure and properties of the steel, the purity of the steel and the heat treatment method of the steel. In some cases, the rolling temperature and deformation level of steel tube will also affect the performance of steel tube.
5. Technological properties, including expansion, flattening, crimping, bending, girth drawing and welding properties of steel pipes.
6. Metallographic structure, including macrostructure and macrostructure of steel pipe.
7. Special requests, requests other than those specified by users when using steel pipes.
This article is supported by Jinan galvanized pipe. For more details, please click on our official website at http://www.jnxjm.com. We will provide you with satisfactory service wholeheartedly.