GB/T 30584-2026Seamless steel tubes for crane jibs (English PDF)

6.5 Delivery Status

6.5.1 Steel pipes of grade BJ450 shall be delivered in normalized or quenched and tempered condition. When the final rolling temperature of the steel pipe is above the critical phase transformation temperature Ar3, and the steel... If the pipe has undergone air cooling, then the steel pipe should be considered to have undergone normalizing.

6.5.2 Steel pipes of grades BJ590, BJ770, BJ890, BJ960, and BJ1020 shall be delivered in quenched and tempered condition.

7.1 Steel grades and chemical composition

7.1.1 The steel grade and chemical composition (smelting analysis) shall conform to the provisions of Table 1.

7.1.2 When the buyer requests finished product analysis, it should be specified in the contract. The permissible deviation of the chemical composition of the finished steel pipes should conform to GB/T 222. According to the regulations.

7.1.3 At the request of the buyer, and upon consultation between the supplier and the buyer, and as specified in the contract, other grades of steel pipes may be used.

7.2 Mechanical Properties

7.2.1 Stretching The room temperature tensile properties of the steel pipes in the delivery condition shall conform to the requirements of Table 2.

7.2.2 Impact

7.2.2.1 Steel pipes with a nominal outer diameter of not less than 76 mm and a nominal wall thickness or average wall thickness (when delivered based on the minimum wall thickness) of not less than

6.5 mm shall When performing Charpy V-notch impact tests, the test temperature and absorbed energy should meet the requirements specified in Table 2.

7.2.2.2 The impact absorption energy specified in Table 2 is the required value for the impact absorption energy of the standard specimen. When using small-sized impact specimens, the smaller... The minimum Charpy V-notch impact absorption energy requirement for the standard-sized specimen should be the requirement for the standard-sized specimen multiplied by the reduction factor in Table 3.

7.2.2.3 As required by the buyer, and upon negotiation between the supplier and the buyer, and as specified in the contract, Charpy V-type defects in other temperatures or directions may be made. The required impact absorption energy value for the impact test shall be determined through negotiation between the supplier and the buyer.

7.3 Surface Quality

7.3.1 The inner and outer surfaces of the steel pipe shall be free from cracks, folds, roll marks, delamination, and scale. These defects shall be completely removed, and the repaired areas shall be rounded. For smooth transitions, the actual wall thickness at the grinding point should not be less than the minimum allowable wall thickness deviation.

7.3.2 The outer surface of the steel pipe shall be free from defects such as oxide scale, pitting, and dense pitting that would affect surface inspection.

7.3.3 Other local defects with a depth not exceeding the wall thickness deviation are allowed to exist.

7.4 Non-destructive testing

7.4.1 Each steel pipe shall undergo ultrasonic testing plus eddy current testing, or ultrasonic testing plus magnetic flux leakage testing, along its entire length. The acceptance level during ultrasonic testing shall meet the following requirements. Complies with the requirements of U2 in GB/T 5777-2019; the acceptance level for eddy current testing should comply with the requirements of E2 or E2H in GB/T 7735; leakage. The acceptance level for magnetic testing shall comply with the requirements of F2 in GB/T 12606.

7.4.2 When the ratio of the outer diameter to the wall thickness of the steel pipe is less than 5, unless otherwise specified in the contract, the acceptance level for ultrasonic testing shall comply with GB/T 5777- The provisions of A.3 in Appendix A of.2019.

7.4.3 The residual magnetism of the steel pipe should not exceed

7.5.1 Outer diameter and wall thickness

7.5.1.1 Unless otherwise specified in the contract, steel pipes shall be delivered according to their nominal outer diameter (D) and nominal wall thickness (S). This shall be determined by both the supplier and the buyer upon the buyer's request. By negotiation, steel pipes can be delivered according to nominal outer diameter and minimum wall thickness (Smin).

7.5.1.2 The nominal outer diameter and wall thickness of the steel pipe shall conform to the provisions of GB/T 17395.Upon request from the buyer and after consultation between the supplier and the buyer, the following specifications may be supplied. Steel pipes of dimensions other than those specified in GB/T 17395.

7.5.1.3 The permissible deviations of the nominal outer diameter and nominal wall thickness of the steel pipe shall conform to the provisions of Table

4.When the steel pipe is delivered with the minimum wall thickness, its minimum... The permissible deviation in wall thickness shall be determined through negotiation between the supplier and the buyer.

7.5.1.4 Upon the request of the buyer and after consultation between the supplier and the buyer, and as specified in the contract, steel pipes with permissible dimensional deviations other than those specified in Table 4 may be supplied.

7.5.2 Length

7.5.2.1 Typical Length Hot-rolled steel pipes are typically 3000mm to 12000mm in length; cold-drawn (rolled) steel pipes are typically.2000mm in length. 12000mm.

7.5.2.2 Fixed Length and Multiple Length 7.5.2.2.1 Upon the buyer's request, and after consultation between the supplier and the buyer, and as specified in the contract, steel pipes may be delivered in fixed lengths or multiples thereof. The fixed length and multiple length of the pipe should be within the normal range. 7.5.2.2.2 The permissible deviation of the fixed length of steel pipe shall conform to the following provisions.

a) When the length is no greater than 6000 mm, 300 mm;

b) When the length is greater than 6000mm, 500mm. 7.5.2.2.3 The permissible deviation for the total length of multiple-length steel pipes is.200 mm. For each cut in the multiple-length pipe, a allowance should be made according to the following specifications.

a) When D<=159mm, the cut allowance is 5mm~10mm;

b) When D >159mm, the cut allowance is 10mm~15mm.

7.5.3 Curvature

7.5.3.1 The curvature of the steel pipe per meter shall not exceed

1.2 mm; the curvature of the steel pipe along its entire length shall not exceed 0.1% of the pipe length, and shall not exceed [a certain value]. 10mm.

7.5.3.2 Based on the requirements of the buyer, and after consultation between the supplier and the buyer, and as specified in the contract, steel pipes with other curvature requirements may be supplied.

7.5.4 Out-of-roundness and uneven wall thickness As required by the buyer, and after consultation between the supplier and the buyer, it is specified in the contract that the out-of-roundness and uneven wall thickness of the steel pipes should not exceed the outer diameter by more than [amount missing]. 80% of the tolerance for wall thickness and other factors.

7.5.5 End Shape

7.5.5.1 For steel pipes with a nominal outer diameter not exceeding 60 mm, the beveling at the pipe ends should not exceed

1.5 mm; for steel pipes with a nominal outer diameter greater than 60 mm, the pipe end beveling should not exceed

1.5 mm. The bevel at the end should not exceed 2.5% of the nominal outer diameter of the steel pipe, and should not exceed 6mm.

7.5.5.2 Burrs at both ends of the steel pipe should be removed.

7.5.6 Weight

7.5.6.1 Steel pipes shall be delivered according to actual weight or theoretical weight. The calculation of the theoretical weight of steel pipes shall comply with the provisions of GB/T 17395. The density of steel is set at

7.5.6.2 As required by the buyer, and after consultation between the supplier and the buyer, and as specified in the contract, the allowable deviation between the actual weight and the theoretical weight of the delivered steel pipes shall be... The difference is.

a) Single steel pipe. ±5%;

b) For each batch of steel pipes with a minimum weight of 10t. ±5%.

8.1 Tensile test specimen

8.1.1 Unless otherwise specified in the contract, tensile tests shall be conducted by sampling along the longitudinal direction of the steel pipe.

8.1.2 For steel pipes with an outer diameter of not less than 219 mm, when required by the buyer and the pipe dimensions allow, the tensile test can be performed by taking samples from a section transversely of the steel pipe. The transverse specimen should be a circular cross-section specimen with a diameter of 10 mm; if the steel pipe size is insufficient to cut a 10 mm specimen, a straight cross-section should be used. Specimens with the largest possible circular cross-section size, either 8 mm or 5 mm in diameter; when the steel pipe size is insufficient to cut a 5 mm circular cross-section specimen. When taking samples, tensile tests should be performed by sampling along the longitudinal direction of the steel pipe. Transverse circular cross-section specimens should be taken from unflattened blanks.

8.2 Impact test specimens Unless otherwise specified in the contract, impact tests shall be conducted along the longitudinal direction of the steel pipe. For steel pipes with an outer diameter of not less than 219 mm, when the purchaser requests... During impact testing, samples can be taken transversely from the steel pipe. Regardless of whether the sample is taken longitudinally or transversely from the steel pipe, the thickness of the impact specimen should be The largest possible size is 10mm, 7.5mm, or 5mm. When the steel pipe size is insufficient to cut a 5mm thick specimen, the impact test... No requirements are made.