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Technical specifications for Q245R(HIC)/Q245R(R-HIC) steel plates and Q345R(HIC)/Q345R(R-HIC) steel plates resistant to hydrogen sulfide corrosion 1. Scope of application These technical specifications apply to Q245R(HIC) and Q245R(R-HIC) steel plates, as well as Q345R(HIC) and Q345R(R-HIC) steel plates, with a thickness of 8 mm to 150 mm, which are used in acidic environments. For steel plates resistant to hydrogen sulfide corrosion that also require SSCC testing, the grades are denoted as Q245R(R-HIC) and Q345R(R-HIC). To meet the various requirements of users and facilitate production management, the S and P requirements for different steel grades are further divided into three levels: I, II, and III. 2. Grade specification: Q245R (HIC)-I refers to the steel grade Q245R; the corrosion test involves only hydrogen-induced cracking resistance testing (HIC). The compositional requirements are P≤0.015 and S≤0.003 as determined by melting analysis ； Finished product analysis: P≤0.015, S≤0.004. Q245R (R-HIC)-I refers to the steel grade Q245R; the corrosion tests include hydrogen-induced cracking (HIC) testing and sulfide stress corrosion cracking (SSCC) testing. The compositional requirements are P≤0.015 and S≤0.003 as determined by melting analysis ； For the finished product, P≤0.015 and S≤0.004. 2 Dimensions, shape, weight, and allowable tolerances: 2.1 The dimensions, shape, weight, and allowable tolerances of the steel plates shall comply with the provisions of GB/T709. 2.2 The thickness deviation shall comply with Class B or Class C of GB/T709, as specified in the contract. 2.3 The steel plates are delivered based on their theoretical weight, with the thickness used for this theoretical calculation being the arithmetic average of the maximum and minimum allowable thicknesses of the steel plates. The density of steel is 7.85 g/cm3. 3 Technical requirements 3.1 Chemical composition The chemical composition of the steel shall comply with the provisions in Tables 1 and 2. Steel grade Designation C Si Mn Al Ca O CE Q245R(HIC) Q245R(R-HIC) Melting analysis ≤0.20 ≤0.35 0.50–1.00 ≥0.020 0.0015–0.0030 ≤0.004 ≤0.36 Finished product analysis ≤0.40 0.45–1.05 Q345R(HIC) Q345R(R-HIC) Melting analysis ≤0.20 0.20–0.55 1.20–1.36 ≥0.020 0.0015–0.0030 ≤0.004 ≤0.45 Finished product analysis 0.20–0.60 Note in Table 1: 1. The Ca value is for reference only and is not used as a acceptance criterion; the values for Ca and O can be replaced by those from the finished product analysis instead of the melting analysis values ； 2. The formula for calculating the carbon equivalent (CE) is as follows: CE = C + Mn/6 + (Cu + Ni)/15 + (Cr + Mo + V)/5. 3. To improve the properties of steel plates, certain micro-alloying elements can be added. It is smelted using an electric furnace combined with secondary refining; Ca treatment is applied during the smelting process, and it should be an inherently fine-grained steel with an actual grain size of grade 5 or higher. 3.3 Delivery condition: normalized. 3.4 Sample condition: All steel plates shall undergo simulated post-weld heat treatment on their test samples. The recommended temperature for this simulated post-weld heat treatment is 620±10°C, with a holding time of 8 hours. The samples should be removed from the furnace when the temperature exceeds 400°C, and the rate of temperature change should be ≤150°C/h. If the conditions differ from those recommended, the specific parameters for the simulated post-weld heat treatment shall be specified in the contract. 3.5 Brinell hardness: The steel plates shall be tested for Brinell hardness after each rolling pass, with the Brinell hardness value being ≤ 200 HB. 3.6 Ultrasonic testing: Steel plates shall be subjected to ultrasonic flaw detection one by one, and the standard level for such testing shall be specified in the contract. 3.7 The inspection items, sampling quantity, sampling methods, and testing methods for each batch of steel plates shall comply with the provisions in Table 4. Over 130 varieties in 12 major categories, as well as various special steel plates. Hydrogen-service SA348Gr11, Hydrogen-service SA387Gr12, Hydrogen-service SA387Gr22, Hydrogen-service 15GrMoR, Hydrogen-service 14Cr1MoR, Hydrogen-service 12Cr2Mo1R, Hydrogen-service 12Cr2Mo1VR, Hydrogen-service 2.25Cr1Mo0.25V, etc. 15CrMoR (HlC), SA387Gr11 (HlC), SA387Gr12 (HlC), SA387Gr22 (HlC), 12Cr2Mo1R (HlC), 14Cr1MoR (HlC), SA516Gr65 (HlC), SA516Gr70 (HlC), 16MnR (A-HlC), 16MnR (HlC), Q345R (HIC), Q245R (HIC). Technical requirements for hydrogen-service steels: (1) Limit on carbon equivalent ； (2) Improve the impact value index (3) Reduce the content of P, S, and O ； (4) In addition to meeting the requirements of GB6654/Gb713 and SA516Gr65/70 standards, the tensile property requirements also include the Z35 requirement ； (5) Limit on hardness value ； (6) Additional anti-HIL or SSCC performance testing ； Actual quality of steel resistant to wet hydrogen sulfide corrosion: 20R(HIC)/20R(R-HIC) ；