This standard specifies the size, shape, technical requirements, inspection and test, packaging, marking and quality certificates of seamless pipes for drilling.
This standard applies to hot-rolled seamless pipes produced by Baoshan Iron and Steel Co., Ltd. for drilling.
2 Normative references
The clauses in the following documents have been adopted as references to this standard. For dated references, subsequent amendments (not including errata content) or revisions do not apply to this standard. However, parties that have reached an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. . For undated references, the latest version is applicable to this standard.
GB/T 222 steel chemical analysis sample sampling method and finished product chemical composition allowable deviation
GB/T 228 metallic materials room temperature tensile test method
Acceptance, packaging, marking and quality certificate of GB/T 2102 steel pipe
GB/T 4336 Carbon steel and low-alloy steel spark source atomic emission spectrometry analysis method (conventional method)
GB/T 7735 eddy current inspection method for steel pipe
3 size, shape and weight
3.1 The outer diameter and wall thickness of the steel tube are in accordance with Table 1. According to the requirements of the buyer, the supply and demand sides agreed to supply steel pipes of specifications other than those shown in Table 1.
Table 1 mm
Outside diameter da Wall thickness S
42.0 5.0, 6.0, 6.5
42.4 5.0 5.6, 6.0, 6.3, 6.8
50.0 5.5, 5.6 6.5
54.0 6.5, 7.0
60.3 7.1, 7.5, 8.0
63.5 7, 7.1
73.0 4.5, 6.5, 8.8, 9.0, 9.19, 10.0
88.9 4.5, 5.0, 8.8, 10.0
89.0 4.5, 5.0, 6.0, 9.0, 10.0
108.0 4.5, 7.1
3.2 The allowable deviations of the outside diameter and wall thickness of the steel pipe are to comply with the requirements of Table 2.
Outer diameter allowable deviation Wall thickness allowable deviation
±1%da +12.5%S -10%S
3.3 The usual length of steel pipe is 6m~12m. After the agreement between supply and demand, the length of the steel pipe can be supplied within the range of 5m~12m, and its allowable length deviation should meet the requirements of Table 3.
Table 3 Length m Allowable deviation mm
≤6 +10 0
>6 +15 0
Note: When supplied according to the length of the fixed length, it is possible to supply the non-inching pipe (not less than 4.5m) which does not exceed the total amount of 10%.
3.4 The curvature of the steel pipe shall not exceed 1.0mm/m.
3.5 Steel tubes are delivered in actual weight.
4 Technical requirements
4.1 The steel grade and chemical composition (smelting analysis) shall comply with the requirements of Table 4.
Brand chemical composition %
C Si Mn Mo P S Cu Cr Ni
no greater than
STM-R780 0.38~0.45 0.15~0.35 1.55~1.85 0.15 ~0.25 0.025 0.020 0.20 0.30 0.30
4.2 Steel pipes are delivered in hot rolled condition.
4.3 The longitudinal mechanical properties of the delivery status of the steel pipe shall comply with the requirements of Table 5.
Brand Mechanical Properties
Specified total extension strength Rt0.5, MPa tensile strength Rm, MPa elongation after breaking A, %
STM-R780 ≥520 ≥780 ≥15
4.4 The eddy current testing of the steel pipe should be carried out one by one to check the compactness of the steel pipe.
5 Inspection and testing
5.1 The dimensions of the steel pipe are measured one by one using suitable measuring tools.
5.2 The inside and outside surfaces of the steel pipe shall be checked by naked eyes with light.
5.3 The test items, sampling quantities and test methods of the steel pipe shall comply with the provisions of Table 6.
No. Inspection item Test method Number of samples
1 chemical composition GB/T 222, GB/T 4336 one sample per furnace
2 Tensile test GB/T 228 One sample per batch
3 eddy current inspection GB/T 7735 by root
5.4 Pipes are inspected, inspected and accepted in batches. Each batch of steel pipes shall consist of steel pipes of the same specification, the same brand, and the same heat number. Each batch of steel pipes is 100 pieces. When the number of remaining steel pipes is not less than 50 pieces, it is a single batch; when there are fewer than 50 pieces, it shall be incorporated into the adjacent batch.
5.5 Tensile test If one of the test results is unqualified, the root steel tube shall be removed and two unqualified items shall be taken from the same batch of steel tubes. If the retest results are not satisfactory, even if one index fails, the whole batch Steel pipe is not accepted.
6 Packaging, Signs, and Quality Certificates
One end of each steel tube should be painted with a red color ring, and the rest of the requirements should meet the requirements of GB/T 2102.
This standard is not equivalent to JIS G3465-1988.
This standard replaces Q/BQB 230-1999.
The main changes from this standard to Q/BQB 230-1999 are as follows:
—— increase the scope of supply specifications;
- Usually the lower limit of length is modified to 6m;
——The requirements for tightening P, S and Cu content;
—— Eddy current testing adopts national standards.