Round steel tube billet with TCVN 2054 – 77

ROUND STEEL PIPE CACBON TCVN 2054 – 77 applies to hot-rolled round pipe billet from carbon steel used for rolling non-welded pipes.


1.1. Symbols of round steel billet convention are as follows
A circular billet of diameter 100 mm from C10 steel is symbolized:
Round tubes D100 TCVN 2054-77 C10 TCVN 1766-75
1.2. The permissible diameters and deviations of round tube billets shall be in accordance with Table 1.
Table 1: mm

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Nominal diameterDeviation allowedNominal diameterDeviation




± 1,3100



± 1,7




± 1,5115







± 2,0
1.3. Round tube steel billets are provided:
– Non-conventional length – from 2 to 9m;
– The conventional length and the multiple of the conventional length are within the range of the non-conventional length and specified in the order.
The allowable deviations of the conventional length and multiples of the conventional length are + 51 mm.

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Chú thích:

  1. Short sections but not less than 800 mm are allowed. When providing non-conventional length short dimensional mass does not exceed 10% of the shipment volume.
    When supplying round tube billets of conventional length and multiples of the conventional length, the short dimensional mass shall be as agreed upon by the two parties.
    The permissible deviation of the truncated round billet length is specified by the two sides
    1.4. The first two segments of the workpiece should be straight. Optional cutting method. The inclination of the head face against the shaft should not exceed 6 mm. The face inclination of the workpiece diameter greater than 100 mm shall not be more than 6% of the nominal diameter. When a section segmentation is allowed to deform locally but not allow the diameter of the workpiece to be less than 8% of the nominal diameter.
    1.5. The local curvature of the round tube blank shall not be greater than 6 mm per 1 m in length.
    The overall curvature should not exceed 0.6% of the length of the workpiece.


The surface of the tube embryo must not have scales, folds, crow’s feet, cracks or impurities visible to the naked eye without using magnifying tools.
Must clean the above defects, cleaning method arbitrary. Cleaning marks should be smooth, comfortable, without iron edges. The width of the cleaning stain should not be less than 6 times its depth.

Trên một mặt cắt vuông góc có cùng một đường kính, độ sâu làm sạch tổng cộng không được lớn 5 % đường kính của phôi và không có quá 3 vết làm sạch với độ sâu cực đại.

Không cần làm sạch các khuyết tật bề mặt cục bộ như: vết xước, vết lõm, vết đốm mà độ sâu không được vượt quá sai lệch âm cho phép của các đường kính hay nứt tóc, bướu mà độ sâu hoặc độ cao không lớn hơn 0,5 mm.


The excess margin at the top and bottom of the round tube shall be not greater than 6 mm.
2.3. The chemical composition of the round tube billet is in accordance with TCVN 1765-75 and TCVN 1766 – 75, steel grade is under the contract between the two parties.
2.4. The rough structure of the embryo (visual inspection) on the impregnated sample shall be free from defects such as shrinkage porosity, air bubbles, cracks, non-metallic impurities, layer sections, shell flips and spots. white.
Air bubbles are not allowed under the shell.
Round tube billet is delivered with particle size, porosity, volatility, phase a, ximentic mesh, certain mechanical properties, determination methods and specific criteria according to the contract between the two parties.

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3.1. Round tube billets are supplied in batches, each batch consisting of billets of the same size, the same batch of smelting.

3.2. Carry out a visual inspection of the entire surface of each workpiece. When necessary, grinding, illumination, impregnation, realization, etc. can be used.

3.3. Analyze the chemical composition of embryos according to TCVN 1811-76 to TCVN 1821-76.

3.4. The macroscopic examination was performed for the first time on two samples. A sample from the section marked with letter A (corresponding to the beginning of the casting piece, below the bean line) and a sample from the segment marked with the letter C (corresponding to the last paragraph of the casting). When the test results of either of the two samples fail, repeat the test with twice as many samples taken in the segment with the unsatisfactory result (either end A or C). If the retest results also fail, do not accept all of paragraphs A and C.

It is permissible to take a sample at the end of paragraph A (or at the beginning of paragraph B) and the beginning of paragraph C (or at the end of paragraph D) one sample each for further testing. If both samples are satisfactory, accept all remaining segments of the consignment (except paragraphs A and C).

If one of the 2 test pieces fails, repeat the test with twice as many samples taken from the segment with the unsatisfactory result. If the retest results are unsatisfactory, the whole batch is accepted.

Production plant reserves the right to take horizontal or vertical samples for rudimentary organization inspection. If the results are satisfactory, then deliver the goods. If billets of the same batch are rolled out to different sizes, then carry out a macroscopic examination of the largest diameter round billet.
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