Chemical composition of 14Cr1MoR(H), technical requirements for placing orders for 14Cr1MoR(H)

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14Cr1MoR(H) is a type of hydrogen-resistant steel. Chemical composition of 14Cr1MoR(H): The chemical composition of this steel shall comply with the specifications in Table 1 (wt%). Table 1: Composition analysis – CSiMnPSMaxCrMo; Melting analysis values: 0.05–0.17, 0.05–0.80, 0.40–0.65; limits: ≤0.010, ≤0.010, 1.15–1.50; 0.45–0.65. Finished product analysis values: 0.05–0.17, 0.46–0.84, 0.37–0.68; limits: ≤0.012, ≤0.012, 1.10–1.55; 0.43–0.67. For elements marked with “*”, the analysis results are to be recorded; these elements are not subject to acceptance criteria based on weight, but they must still meet the requirements regarding J and X coefficients. Under the premise of ensuring melting analysis, finished product analysis may not be conducted. (3) The temper embrittlement coefficient shall meet the following requirement: X = (10P + 5Sb + 4Sn + As) ≤ 15, where the values of these elements are to be substituted in terms of their PPM content; for example, 0.01% is replaced by 100 ppm. J=（Si+Mn）X(P+Sn)X≤180, where the elements are substituted in terms of their weight percentage; for example, 0.01% is replaced by 0.01. 4.2 Smelting method for 14Cr1MoR(H): A smelting process that combines an electric furnace with off-furnace refining and vacuum degassing is used, and secondary electroslag remelting is also possible. The steel plate shall be essentially fine-grained normalized steel. 4.3 Delivery condition: The steel plates are delivered in the normalized (with allowed accelerated cooling) + tempered condition. 4.4 The mechanical properties and processability shall meet the requirements specified in Table 2. Table 2: Units of measurement for test values. Tensile strength at room temperature: Rm ≥ 520–680 MPa; Tensile strength at room temperature: Rp0.2 ≥ 310 MPa; Elongation at room temperature: A ≥ 19%; Reduction in cross-sectional area upon tensile testing: Z ≥ 45% (for round specimens) or ≥ 40% (for plate specimens). Charpy impact energy at 0°C (V-notch): Average value at +10°C ≥ 55 J. Yield strength under high-temperature tensile testing at 0°C: Rp0.2 – see notes, in MPa. Bend test at room temperature: No cracks after bending by 180°. Note: ① When conducting impact tests, it is necessary to record the lateral expansion value and the percentage of fibrous fracture surfaces for reference. ②The diameter of the bending center for room temperature bending tests is as follows: Sample thickness T (mm) – Diameter of bending center (mm): T≤25: 1.5T; 25<T≤50: 2.0T; T>50: 2.5T. ③Steel plates with a thickness greater than 20 mm can be subjected to high-temperature tensile tests. The temperature for these tests is specified in the contract, and their Rp0.2 value must comply with the requirements of GB 713-2008 (intermediate temperatures are calculated using interpolation methods), and this information must also be specified in the contract. 5 Hydrogen-resistant grades: 14Cr1MoR, hydrogen-resistant SA387Gr11CL2, and 14Cr1MoR(H). Test methods and inspection rules: Mechanical property tests are carried out on the delivered steel sheets. The locations from which samples are taken, the test items, test methods, number of samples, and heat treatment conditions are shown in Table 3. If the length of a finished sheet exceeds 7 m, another sample is taken from the other end to conduct the various mechanical property tests listed in Table 2.

Table 3: Locations for sampling, test items, test methods, number of samples, and sample locations
Simulation of post-weld heat treatment: ②
Head steel plates, cylinder steel plates: Tensile testing at room temperature: ③ GB/T 228; 2 samples taken from Sample A, 1 sample with its axis perpendicular to the direction of testing; 1 sample for maximum PWHT condition, 1 sample for minimum PWHT condition. Tensile testing at high temperatures: ③⑤ GB/T 4338; 2 samples taken from Sample A, 1 sample with its axis perpendicular to the direction of testing; 1 sample for maximum PWHT condition, 1 sample for minimum PWHT condition. Charpy (V-notch) impact testing at +10°C: GB/T 229; 2 sets of samples taken from Sample A, totaling 6 samples, tested at 4 points, with the sample axes perpendicular to the direction of testing: ①④; 1 set for maximum PWHT condition, 1 set for minimum PWHT condition. Room temperature bending test: GB/T 232; 1 sample taken from each steel sheet, with the sample axis perpendicular to the direction of testing. Analysis of the finished product: GB/T 223; 1 sample taken from each steel sheet, tested at 4 points: ①. Condition of delivery. Note: In Table 3, the capital letters “T” indicate the nominal thickness of the steel sheet. ②The maximum post-weld heat treatment (Max.PWHT) and minimum post-weld heat treatment (Min.PWHT) are carried out according to the following procedures: Max.PWHT: 690±10℃ for X(18-20) hours; Min.PWHT: 690±10℃ for X(6-8) hours. ③ When the steel plate thickness is ≤30 mm, tests should be conducted using specimens of the full thickness; when the thickness is greater than 30 mm, the specimen axis should be located at 1/4 of the plate thickness. ④For the impact energy test specimen, the axis of the specimen is located at a depth of 1/4 of the plate thickness or as close to 1/4 of the plate thickness as possible; the notch is made on the side of the specimen, with its axis perpendicular to the rolled surface of the steel plate. If the impact performance does not meet the requirements specified in Table 2, three additional specimens shall be taken from the same steel plate (or the same billet) for testing. The arithmetic average of the impact energy values of the six specimens taken in total must be no less than 55 J; it is acceptable for two specimens to have a value of less than 55 J, but only one specimen may have a value of less than 48 J. ⑤ The qualified criteria are indicated in Note ③ of Table 2 (applicable to steel plates with a thickness greater than 20 mm). For hydrogen-service applications, ultrasonic testing is required for 14Cr1MoR and SA387Gr11CL2 steel plates, as well as for 14Cr1MoR(H) steel plates; each steel plate is subjected to ultrasonic testing, and the testing standards and acceptable quality levels are specified in the contract. 10 Marking of hydrogen-service 14Cr1MoR, hydrogen-service SA387Gr11CL2, and 14Cr1MoR(H) steel plates: Comply with the provisions of GB 713-2014. 10 For matters not covered herein, the relevant provisions of standard GB 713-2014 shall apply. F Additional supplementary requirements: The various clauses of these additional requirements shall be implemented only when explicitly specified in the contract. The options are as follows: F1 As agreed upon by both the supplier and the buyer, room temperature tensile testing, high temperature tensile testing, and Charpy (V-notch) impact testing can be conducted using samples taken from plates with a thickness of TXT/2, in accordance with the requirements in Table 3; the performance criteria shall meet those specified in Table 2, and the sampling locations specified in the original Table 3 are no longer applicable. F2: As agreed upon between the supplier and the buyer, steel plates with a thickness of ≤80mm can undergo low-temperature impact testing in accordance with the requirements in Table 4, as an alternative to the 0°C impact energy test. The sampling and testing methods shall follow the provisions related to the 0°C impact energy test outlined in Article 8; the sample locations shall be determined in accordance with Table 3 (when there is a F1 requirement, the sample location is TXT/2, and the TXT/4 rule does not apply). II. Low-temperature impact performance testing: Applicable thickness range – Impact temperature: Unit value ≤80mm; Temperature: -10°C. Required average impact energy: ≥41 J. If the impact performance does not meet the requirements specified in Table 4, three additional samples shall be taken from the same steel plate (or the same billet). The arithmetic average of the impact energies of these six samples must be at least 41 J. It is allowed for two samples to have an impact energy lower than 41 J, but only one sample may have an impact energy lower than 34 J. Hardness of F3 steel plate: Samples from the steel plate can be taken for hardness testing, and the hardness of such samples after minimum simulated welding heat treatment shall not exceed 220HB. The sampling location shall follow the provisions in the sampling schematic in Table 3, with the inspection location being at 1/4 of the plate thickness. Inspection of austenite grain size in F4 steel plates: The austenite grain size of the steel plates shall be at least grade 5; the specimens are in their as-delivered condition, and the inspection method shall comply with the provisions of GB/T6394. The sampling location shall follow the provisions in the sampling schematic in Table 3, with the inspection location being at 1/4 of the plate thickness. Tensile test for F5 steel plate thickness: The steel plate can undergo a tensile test for thickness in accordance with the GB 5313 standard, with the specimen representing the minimum condition simulating post-weld heat treatment. F6 inclusions inspection: Steel plates can be provided with an inclusions grade inspection in accordance with the GB/T 10561 standard, using specimens in their as-delivered condition. The sampling location shall follow the provisions in the sampling schematic in Table 3, with the inspection location being at 1/4 of the plate thickness.