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Q245R(HIC ） / （ R-HIC ）
Q245R (HIC)/Q245R (R-HIC) for hydrogen sulfide corrosion resistance steel plate And Q345R (HIC)/Q345R (R-HIC) steel plate supply technical conditions
1. Scope of application
The technical conditions are applicable to the steel plates with a thickness of 8mm~150mm Q245R (HIC), Q245R (R-HIC) and Q345R (HIC), Q345R (R-HIC) used in acidic environment. The grades of hydrogen sulfide resistant steel plates added to SSCC inspection items are indicated by Q245R (R-HIC), Q345R (R-HIC).
In order to meet different requirements of users and facilitate production management, S and P requirements for steel grades are divided into three levels: I, II and III.
2. Brand description
Q245R (HIC) - I refers to the steel grade Q245R. The corrosion test is only conducted for hydrogen induced cracking resistance (HIC). The composition requires melting analysis P ≤ 0.015, S ≤ 0.003; the finished product analysis P ≤ 0.015, S ≤ 0.004.
Q245R (R-HIC) - I refers to the steel grade Q245R. The hydrogen induced cracking (HIC) and sulfide stress corrosion (SSCC) tests are conducted for the corrosion test. The composition requires melting analysis P ≤ 0.015, S ≤ 0.003; the finished product analysis P ≤ 0.015, S ≤ 0.004
2 Dimension, shape, weight and allowable deviation
2.1 The size, shape, weight and allowable deviation of steel plate shall comply with the provisions of GB/T709.
2.2 Thickness deviation shall be in accordance with GB/T709 Class B or Class C, and shall be noted in the contract.
2.3 The steel plate shall be delivered according to the theoretical weight. The thickness used for the theoretical weight measurement is the arithmetic mean of the allowable larger thickness and smaller thickness of the steel plate. The density of steel is 7.85g/cm three 。
3 Technical Requirements
3.1 Chemical composition
The chemical composition of steel shall comply with the provisions in Table 1 and Table 2.
Steel grade | Brand | C | Si | Mn | AL | Ca* | O* | CE** |
Q245R(HIC）Q245R（R-HIC） | Smelting analysis | ≤ zero point two zero | ≤ zero point three five | 0.50- one | ≥0.020 | 0.0015- zero point zero zero three zero | ≤0.004 | ≤ zero point three six |
Finished product analysis | ≤0.40 | 0.45- one point zero five |
Q345R(HIC）Q345R（R-HIC） | Smelting analysis | ≤0.20 | 0.20-0.55 | 1.20- one point three six | ≥0.020 | 0.0015- zero point zero zero three zero | ≤0.004 | ≤0.45 |
Finished product analysis | 0.20-0.60 |
Table 1
Note: (1) The Ca value is only for reference and is not used as an acceptance condition. The Ca and O content can be replaced by the melting analysis value by the finished product analysis value;
(2) The calculation formula of carbon equivalent (CE) is as follows: CE=C Mn/6 (Cu Ni)/15 (Cr Mo V)/5
(3) In order to improve the properties of the steel plate, some micro alloying elements can be added.
Table 2
Grade | component | P | S |
Ⅰ | melting | ≤0.015 | ≤0.003 |
finished product | ≤0.015 | ≤0.004 |
Ⅱ | melting | ≤0.010 | ≤0.002 |
finished product | ≤0.010 | ≤0.003 |
Ⅲ | melting | ≤0.008 | ≤0.002 |
finished product | ≤0.008 | ≤0.002 |
3.2 Smelting method
It is smelted by electric furnace refining, and the smelting process is treated with Ca, which should be essentially fine grain steel, and its actual grain size is 5 or above.
3.3 Delivery status: normalizing.
3.4 Sample status: all steel plates shall be subject to simulated welding heat treatment The recommended simulated post weld heat treatment temperature is 620 ± 10 ℃, holding time is 8 hours, the temperature is above 400 ℃, and the temperature rise and fall speed is ≤ 150 ℃/h. If it is inconsistent with the recommended heat treatment system, the specific simulated post weld heat treatment system shall be noted in the contract.
3.5 Mechanical properties
3.5.1 The mechanical properties of the steel plate sample in the simulated post weld heat treatment state shall comply with the provisions in the following table.
Table 3
Steel grade | thickness (mm) | ReL MPa | Rm MPa | A % | Shock temperature ℃ | Impact value J | 180 ° bending test b=2a | Thickness direction performance ψ Z (%) |
average value | Single value |
Q245R(HIC） Q245R（R-HIC） | 8-16 | ≥245 | 400-520 | ≥25 | -20 | Average value ≥ 34, single value ≥ 24 | d=1.5a | ≥35 | ≥25 |
>16-36 | ≥235 |
>36-60 | ≥225 |
>60-100 | ≥205 | 390~510 | ≥24 | d=2a |
>100-150 | ≥185 | 380-500 |
Q345R(HIC） Q345R（R-HIC） | 8--16 | ≥345 | 510-640 | ≥21 | -30 | Average value ≥ 34, single value ≥ 24 | d=2a | ≥35 | ≥25 |
>16--36 | ≥325 | 500-630 | d=3a |
>36--60 | ≥315 | 490-620 |
>60-100 | ≥305 | 490-620 | ≥20 |
>100-150 | ≥285 | 480-610 |
Note: (1) The steel plate with thickness ≥ 15mm is used for thickness direction performance;
3.5.2 Brinell hardness: the steel plate shall be tested for Brinell hardness one by one, and the Brinell hardness value shall be ≤ 200HB.
3.6 Ultrasonic inspection: steel plates shall be subject to ultrasonic inspection one by one, and the inspection standard level shall be specified in the contract.
3.7 The inspection items, sampling quantity, sampling method and test method of each batch of steel plates shall comply with Table 4.
Table 4
Inspection items | Sampling quantity (piece) | Sampling method | test method |
chemical analysis | *Smelting analysis | 1 (each furnace) | GB/T20066 | GB/T223 |
*Finished product analysis | 1 (rolling sheet by sheet) |
stretching | 1 (rolling sheet by sheet) | GB/T2975 | GB/T228 |
bend | 1 (rolling sheet by sheet) | GB/T2975 | GB/T232 |
Thickness direction performance | 3 (rolling sheet by sheet) | GB/T5313 | GB/T5313 |
Grain size | 1 (each furnace) | YB/T5148-93 |
Brinell hardness | 1 (rolling sheet by sheet) | GB/T231 |
ultrasonic examination | Sheet by sheet | As indicated in the contract |
*HIC test | See additional requirements | As indicated in the contract |
to attack | 3 (rolling sheet by sheet) | GB/T2975 | GB229 |
*High temperature tension | 1 (rolling sheet by sheet) See additional requirements | GB/T2975 | GB/T4338 |
As indicated in the contract |
*SSCC test | As indicated in the contract |
Note: Items marked with * are optional.
4. Inspection rules
4.1 The surface quality of steel plate shall comply with GB713-2008.
4.2 The packaging, marking and quality certificate of steel plate shall comply with GB713-2008.
4.3 Matters not covered shall comply with GB713-2008
Additional requirements (guaranteed only when users put forward requirements and indicate in the contract)
1. Simulate post weld heat treatment system
2. High temperature tension (negotiated by both parties)
3. Low temperature shock (negotiated by both parties)
4. Inspection rules for hydrogen induced cracking (HIC) test of steel plate
A. Test method for resistance to hydrogen induced cracking (HIC), one of which is optional
(1) Implement NACE TM0284 standard, use solution A, and the average value of three samples is: CLR ≤ 10%; CSR≤3%；CTR≤1%。
(2) Execute NACE TM0284 standard, use solution B, and the average value of three samples is: CLR ≤ 10%; CSR≤3%；CTR≤1.5%。
(3) Implement GB8650 standard, use solution A, and the average value of three samples is: CLR ≤ 10%; CSR≤3%；CTR≤1.5%。
(4) Implement GB8650 standard, use solution B, and the average value of three samples is: CLR ≤ 10%; CSR≤3%；CTR≤1.5%。
PH: medium pH; CLR: percentage of crack length; CSR: crack sensitivity percentage; CTR: Crack thickness percentage
B. HIC test acceptance rules
HIC test shall be accepted in batches. Each batch consists of steel plates with the same heat number, thickness and heat treatment system. When the thickness is not more than 30mm, take a group of samples, and the sample size is plate thickness * 20mm * 100mm; When the thickness is more than 30mm, take a group of samples from the 1/2 of the thickness, and the sample size is 20mm * 20mm * 100mm.
5. Inspection rules for sulfide stress corrosion test of steel plate
A. Sulfide stress corrosion resistance (SSCC) test method, one of which is optional
(1) Implement GB4157 standard.
(2) Execute NACE TM0177 standard
B. SSCC Test Acceptance Rules
Q245R（R-HIC） door Threshold stress ≥ 180MPa, Q345R (R-HIC) threshold stress ≥ 230MPa, SSCC test shall be accepted in batches, and a group of samples shall be taken from 1/2 of the thickness of steel plate with larger thickness in the same contract number.
