As cold seamless tube supplier, our company shall first ensure that the process of cold drawn seamless steel tube conforms to international standards. The most important process in the production of cold drawn seamless tube is as follows:
Cold drawn seamless tube quality important first is the average degree of wall thickness, the thickness of the cold drawn seamless tube cannot get manipulation will immediately harm seamless steel tube quality and utility, cold drawn seamless tube, large size cold drawn seamless tube is generally used in all kinds of mechanical processing and manufacturing, thin-walled parts processing, cold drawn seamless tube wall thickness of the mean will harm the quality of the middle and later processing parts immediately, cold drawn seamless tube wall thickness cannot get control, is the overall cannot get strict check on strictly the quality of the seamless steel tube.
In cold drawn seamless tube zero cut within the time limit, it is important to note the manufacturing speed control situation, in the production of cold drawn seamless pipe manufacturing processing and the manufacture processing of general plate way different, generally medium plate production and manufacturing to the requirement of speed is not very high, but if in the cold drawn seamless tube manufacturing period, too fast will lead to the quality of the plate due to the difficulty, some still will appear crack, therefore when carries on the production and processing to pay attention to the practice, and manufacturing speed shoulds not be too fast, can according to the thickness of plate and specifications established production speed, Avoid waste parts due to improper methods, which are responsible to the manufacturer.
As cold seamless tube supplier, ensure that all cold drawn seamless tube products are inspected before delivery, such as chemical composition, dimensional accuracy, water pressure test, spectral inspection, etc. In the same way, when purchasing seamless steel pipe and cold-drawn seamless pipe products, the user should also do some simple acceptance of cold-drawn seamless pipe products, such as checking the production standard of steel pipe brand, checking the specification of cold-drawn seamless pipe, measuring the dimensional precision of seamless steel pipe and checking the quantity of steel pipe.
1. Chemical composition
The content of harmful chemical elements AsSnSbBiPb and gas NHO are required. In order to improve the uniformity of chemical composition and the purity of steel, reduce the nonmetal inclusions in the tube billet and improve its distribution, the steel is often refined by using the refining equipment outside the furnace, and even remelting and refining the tube billet by the electroslag furnace.
2. Dimension accuracy and shape
The geometrical dimensions of seamless steel pipe mainly include the outer diameter, wall thickness, ellipticity, length, bending degree, cutting Angle of tube end face, bevel Angle and blunt side, cross section size of hetero-steel pipe and so on.
3. Surface quality
The standard specifies the requirements of "smooth surface" of seamless steel tube. Common defects are: crack, hair lines, folding, folding, rolling, inside straight, outside straight, separation, scar, pit, convex hull, hemp pit (hemp surface), scratch (scratch), inside spiral road, outside spiral road, blue line, recessing, roll, etc. There are allelic dangerous defects of crack, fold in, fold out, crack, disjunction, scar, pit and convex hull. The surface of steel pipe, blue line, scratch, slight inside and outside straight, slight inside and outside spiral, concave, roll printing are general defects.
4. Physical and chemical properties
Including the mechanical properties at room temperature and mechanical properties at a certain temperature (thermal strength and low temperature properties) and corrosion resistance (such as oxidation resistance, water resistance, acid and alkali resistance, etc.) generally depends on the chemical composition of steel, structural properties, steel purity and steel heat treatment mode. In some cases, the steel tube rolling temperature and deformation degree will also affect the performance of the steel tube.
5. Technological performance
Including steel tube flaring, flattening, rolling, bending, ring drawing and welding properties.
6. Metallographic structure
Including low - power structure and high - power structure of steel pipe.
7. Special requirements
In the use of steel pipe in the user of the standard requirements.