Krivoy Rog calibrated steel bar 2, 4, 6, 8, 10, 12mm, round timber metal (black steel) different diameters, silver bar U8A, 65G, 60S2A, 30HGSA, 9XC

Krivoy Rog calibrated steel bar 2, 4, 6, 8, 10, 12mm, round timber metal (black steel) different diameters, silver bar U8A, 65G, 60S2A, 30HGSA, 9XC

Outwardly, a calibrated circle is similar to an ordinary steel bar, only more even, accurate. In fact, he is what he is - a calibrated round bar.
A simple bar, even made according to state standards, allows quite significant deviations in geometry, in surface accuracy. Accordingly, it is less demanding in terms of packaging, storage, and transportation.
The circle calibrated is used as preparation for details of mechanisms, for bolts, hairpins, shaft and other products. Therefore, the requirements for the accuracy of its execution are higher.
It is made from the same hot-rolled bar by additional rolling or drawing. At the same time, special attention is paid to the quality of the geometry, the absence of deviations. The raw material can be both carbon and alloy steel, including stainless steel. The same requirements are imposed on the quality of raw materials as in the manufacture of conventional bars.
In some cases, the surface of the circle is additionally polished, as a result, an almost mirror surface is obtained. This variety is popularly called "silver". However, in any case, standards require that products be protected against corrosion by oil. An exception is made only for a circle made of stainless steel; it is also possible to do without oil by agreement with the customer.
Features of manufacturing and delivery
You can buy a calibrated circle of various sizes from steel of various grades. The diameter varies from 3 to 270 mm or more. With a size of up to 5 mm (and upon agreement with the customer - up to 25 and even more), the circle can be supplied in coils. If the diameter exceeds this figure, then it is customary to manufacture rolled products in bars of measured and random lengths.
The bars are supplied bundled, each bundle must be marked. In particular, the diameter of the bar, steel grade, type of manufacturing accuracy (high, increased, ordinary accuracy) are indicated.
The length of the bars can be from 1.5 to 6.5 m, depending on the type of steel. If necessary, you can buy a calibrated circle, cut into pieces of the desired length. It is worth remembering that the state standard assumes the absence of burrs and bends.
If the process requires the use of special steel grades and non-standard types of anti-corrosion lubricant, then this should be discussed with the supplier at the order stage.
Circle calibrated GOST 7417-75.
Calibrated steel is a sectional hot-rolled steel subjected to additional processing by cold drawing with small reductions, which is necessary to obtain more accurate profile dimensions, improve surface quality, and improve the physical and mechanical properties of steel. By subjecting the calibration to hot-rolled round bars, a calibrated circle is obtained. The curvature formed during the drawing of steel is eliminated on straightening machines, giving the rolled product the greatest accuracy. Calibrated round steel, calibrated circle has high surface quality characteristics and high plastic properties.
A steel circle calibrated to GOST 7417-75, made of various steel grades, goes on sale. The choice of a specific steel grade is usually determined by the subsequent scope of this type of rolled metal. The required accuracy of rolling this metal product also depends on its further use: a steel circle can be of high, increased and ordinary accuracy.
Circles are divided by length into:

     dimensional - the length of one specific length (usually it is 6m);
     not measured - length from 2 to 6 m any of the given interval.

Also, when supplying a measured length, up to 5% of unmeasured lengths are allowed.
By agreement with the client, the circle can be the entire measured length, but the factories, in this case, increase its selling price.
Also, hot-rolled circle can be classified according to the chemical composition of the steel:

     construction circles (steels 20, 35, 45);
     carbon circles (St 3);
     low-alloy wheels (steel 09G2S);
     alloy wheels (steel 20KhN3A, 30KhGSA, 40Kh, 18KhGT, 25KhGT, 20Kh2N4A, 40KhN, 40KhN2MA);
     stainless circles (steel 20X13 and 40X13);

​GOST calibrated wheel
There is also such a thing as a calibrated circle - this is a circle that has undergone a decrease in diameter in a cold state. It is important to distinguish between a calibrated wheel and a turning wheel. The main difference between these wheels is that the turning wheel has a high surface quality, the same as that of the calibrated one, but its internal structure, as it was, remains the structure of a hot-rolled wheel. During the production of a calibrated wheel, its crystal lattice changes and acquires higher strength characteristics. It is manufactured according to GOST 7417-57.
Calibrated circle
In comparison with hot-rolled calibrated circle is characterized by greater geometry accuracy, improved surface quality and strength properties. Rental can be made in the following ways:
     cold rolling is carried outsimilarly hot, but does not require heating the billet (hot-rolled wheel) to high temperatures;
     drawing involves pulling a round hot-rolled bar through a die or die (annular tool), which has a smaller cross section than the cross section of the original workpiece.
Finished steel, if necessary, undergoes additional processing (polishing, grinding), which reduces surface roughness and improves dimensional accuracy.