1 Scope This standard specifies the dimensions, shapes, technical requirements, inspection and testing, packaging, marking, and quality certificates for seamless steel pipes used in drilling.Steel pipe的尺寸、外形、技术要求、检验与试验、包装、标志和质量证明书。 This standard applies to seamless hot-rolled pipes for drilling produced by Baoshan Iron & Steel Co., Ltd.Steel pipe。 2 Normative References The provisions of the following documents become provisions of this standard through reference. For referenced documents with a date, all subsequent amendments (excluding errata) or revisions do not apply to this standard; however, parties are encouraged to study whether the latest versions of these documents can be used based on this standard. For referenced documents without a date, their latest versions apply to this standard. GB/T 222 Sampling methods for chemical analysis of steel and allowable deviations in chemical composition of finished products GB/T 228 Metallic materials - Room temperature tensile test methods GB/T 2102 Steel pipe's acceptance, packaging, marking and quality certificate GB/T 4336 Atomic emission spectrometry method (conventional method) for spark source analysis of carbon steel and medium-low alloy steel GB/T 7735 Steel pipe's eddy current testing method 3 Dimensions, Shapes and Weights Steel pipe's outer diameter and wall thickness shall comply with the provisions of Table 1. According to the requirements of the purchaser, specifications outside Table 1 may be supplied as agreed by both parties.Steel pipe。 (Table1) mm (Outer 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)) (76。0 (6。0)) (88。9 (4。5、5。0、8。8、10。0)) 4 Technical Requirements 127.0 4.5 表2 外径允许偏差 壁厚允许偏差 ±1％da +12.5％S －10％S 表3 长度 m 允许偏差 mm ≤6 +10 0 ＞6 +15 0 注：按定尺长度供货时，可配供不超过总量10％的非定尺管（不小于4.5m）。 4 技术要求 4.1 钢的牌号及化学成分（熔炼分析）应符合表4的规定。 表4 牌 号 化 学成分 ％ C Si Mn Mo P S Cu Cr Ni 不大于 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 表5 牌 号 力学性能 规定总延伸强度 Rt0.5 ，MPa 抗拉强度 Rm ，MPa 断后伸长率 A ， ％ STM-R780 ≥520 ≥780 ≥15 5 检验与试验 5.3 Steel pipeThe inspection items, sampling quantity, and testing methods should comply with the provisions of Table 6. Table 6 Serial Number Inspection Item Testing Method Sampling Quantity 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 Testing GB/T 7735 One by one 5.4 Steel pipeInspection, testing, and acceptance should be conducted by batch. Each batchSteel pipeshould consist of the same specification, same grade, and same furnace number.Steel pipeEach batchSteel pipeconsists of 100 pieces; if the remainingSteel pipe's quantity is not less than 50 pieces, it shall be treated as a separate batch; if less than 50 pieces, it should be merged into an adjacent batch. 5.5 If any test result of the tensile test is unqualified, that piece should be removed, and another two pieces should be taken from the same batch.Steel pipe剔除，并从同一批Steel pipe中再取2根Steel pipe复验不合格项目，复验结果即使有一个指标不合格，则整批Steel pipe, if even one indicator is unqualified in the retest results, the entire batch will not be accepted. Steel pipe. Each end of each piece should have a red color ring printed on it; other requirements should comply with GB/T 2102 regulations. (Additional Note: The degree of consistency of this standard with JIS G3465-1988 is non-equivalent.) (This standard replaces Q/BQB230-1999.) (The main changes compared to Q/BQB230-1999 are as follows:) - Increased supply specification range; - The lower limit for normal length modified to be six meters; - Stricter requirements for P, S, Cu content; - Eddy current testing adopts national standards. | 
