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High Strength Structural Steel Plates Q550C/D/E/F

GB/T 16270—2009 Fully Compliant | Quenched & Tempered delivery | Thickness ≤150mm | Quality grades C / D / E / F

📄 Full standard technical data: Chemical Composition · Mechanical Properties · Impact Energy · CEV · All normative references
1 Scope

This document specifies the designation, dimensions, shape, weight and tolerances, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of high strength structural steel plates. This document applies to steel plates with thickness not greater than 150 mm delivered in quenched and tempered condition (quenching + tempering).

2 Normative References

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

No. Standard No. Title
1 GB/T 222 Permissible tolerances of chemical composition for finished steel
2 GB/T 223.5 Reduced silicomolybdic complex photometric method for acid-soluble silicon content
3 GB/T 223.9 Chrome azurol S spectrophotometric method for aluminum content
4 GB/T 223.11 Ammonium persulfate oxidation volumetric method for chromium content
5 GB/T 223.14 Molybdenum reagent extraction photometric method for molybdenum content
6 GB/T 223.16 Chromotropic acid photometric method for titanium content
7 GB/T 223.17 Diantipyrylmethane photometric method for titanium content
8 GB/T 223.19 Neocuproine-chloroform extraction photometric method for copper content
9 GB/T 223.23 Dimethylglyoxime spectrophotometric method for nickel content
10 GB/T 223.26 Thiocyanate spectrophotometric method for molybdenum content
11 GB/T 223.40 Chlorosulfophenol S spectrophotometric method for molybdenum content
12 GB/T 223.53 Flame atomic absorption spectrometric method for copper content
13 GB/T 223.54 Flame atomic absorption spectrometric method for nickel content
14 GB/T 223.58 Sodium arsenite-sodium nitrite titrimetric method for manganese content
15 GB/T 223.59 Antimony phosphomolybdate blue photometric method for phosphorus content
16 GB/T 223.60 Perchloric acid dehydration gravimetric method for silicon content
17 GB/T 223.62 Butyl acetate extraction photometric method for phosphorus content
18 GB/T 223.63 Sodium periodate photometric method for manganese content
19 GB/T 223.64 Flame atomic absorption spectrometric method for manganese content
20 GB/T 223.68 Potassium iodate titration method after combustion in tube furnace for sulfur
21 GB/T 223.69 Gas volumetric method after combustion in tube furnace for carbon
22 GB/T 223.76 Flame atomic absorption spectrometric method for vanadium content
23 GB/T 223.78 Curcumin direct photometric method for boron content
24 GB/T 228 Metallic materials - Tensile testing at ambient temperature
25 GB/T 229 Metallic materials - Charpy pendulum impact test method
26 GB/T 247 General rules of packaging, marking and quality certificate
27 GB/T 709 Dimensions, shape, weight and tolerances for hot-rolled plates
28 GB/T 2970 Ultrasonic testing method for thick steel plates
29 GB/T 2975 Location and preparation of samples for mechanical testing
30 GB/T 4336 Spark discharge atomic emission spectrometric method for carbon & low-alloy steel
31 GB/T 14977 General requirements for surface quality of hot-rolled steel plates
32 GB/T 17505 General technical delivery requirements for steel and steel products
33 GB/T 20066 Sampling and preparation of samples for chemical composition
34 GB/T 20123 Infrared absorption after combustion in high-frequency furnace (total C&S)
35 GB/T 20125 Determination of multi-element content - ICP-AES
36 GB/T 20126 Determination of low carbon content - Infrared absorption after induction furnace combustion
37 YB/T 081 Rounding rule and determination principle for metallurgical standard values
3 Designation Method

The designation consists of: the Chinese Pinyin initial letter for yield strength, the specified minimum yield strength value, and the quality grade symbol (C, D, E, F).
Example: Q550E — Q: initial letter of "Qu" (yield strength); 550: minimum yield strength (MPa); E: quality grade symbol.

4 Ordering Information

When ordering, the user shall provide: a) document number; b) designation; c) dimensions; d) delivery condition; e) edge condition; f) weight; g) application; h) other requirements.

5 Dimensions, Shape, Weight and Tolerances

5.1 The dimensions, shape, weight and tolerances shall comply with GB/T 709.
5.2 Other dimensions, shape and tolerances may be supplied by agreement between supplier and buyer.

6 Technical Requirements
6.1 Designation and Chemical Composition

6.1.1 The designation, chemical composition (ladle analysis) and carbon equivalent CEV shall comply with Table 1.

6.1.2 Upon agreement between supplier and buyer and indicated in the contract, carbon equivalent CET may be supplied: CET = C+(Mn+Mo)/10+(Cr+Cu)/20+Ni/40.

6.1.3 Permissible tolerances for finished chemical composition shall comply with GB/T 222.

Grade Chemical composition (mass fraction) / % max CEV max
C Si Mn P S Cu Cr Ni Mo B V Nb Ti Thickness≤50 Thickness>50~100 Thickness>100~150
Q550C 0.20 0.80 1.70 0.025 0.015 0.50 1.50 2.00 0.70 0.005 0.12 0.06 0.05 0.65 0.77 0.83
Q550D 0.20 0.80 1.70 0.025 0.015 0.50 1.50 2.00 0.70 0.005 0.12 0.06 0.05
Q550E 0.20 0.80 1.70 0.020 0.010 0.50 1.50 2.00 0.70 0.005 0.12 0.06 0.05
Q550F 0.20 0.80 1.70 0.020 0.010 0.50 1.50 2.00 0.70 0.005 0.12 0.06 0.05

NOTE a The values for Cu, Cr, Ni, Mo are maximum. For quenched and tempered steel, B content ≤0.0005% and H ≤0.0002% if applicable.

NOTE b CEV formula: CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15.

NOTE c Residual elements B and H may be omitted if guaranteed by the supplier.

6.2 Steelmaking Process & 6.3 Delivery Condition

6.2 Steel shall be made by converter or electric arc furnace.
6.3 Plates shall be delivered in quenched and tempered condition (quenching + tempering).

6.4 Mechanical Properties and Process Performance

6.4.1 The mechanical properties and process performance shall comply with Table 2.

6.4.2 Charpy impact energy shall be calculated as arithmetic mean of three specimens; one individual value may be lower than specified value but not less than 70% of the specified value.

Grade Yield strength ReH/MPa (min) Tensile strength Rm/MPa A% (min) Impact energy KV₂/J (longitudinal) min
≤50 >50~100 >100~150 ≤50 >50~100 >100~150 0℃ -20℃ -40℃ -60℃
Q550C 550 530 490 640~820 590~770 16 47 — — —
Q550D 16 — 47 — —
Q550E 16 — — 34 —
Q550F 16 — — — 34

NOTE a For thickness >100~150mm, tensile strength and impact values may be subject to agreement between supplier and buyer.

NOTE b Subsized impact specimens for thickness <12mm as per 6.4.3: 8~12mm → 7.5×10×55mm result ≥75% of specified value; 6~8mm → 5×10×55mm result ≥50%; no impact test for thickness <6mm.

6.4.3 For thickness <12mm, subsize impact specimens shall be used as specified in NOTE b above.
6.5 Surface Quality

6.5.1 The plate surface shall be free from cracks, blisters, scabs, folds, inclusions and delamination. Cleaning depth ≤ half thickness tolerance.
6.5.2 Other defects depth ≤ half thickness tolerance.
6.5.3 Welding repair permitted by agreement; if repaired after quenching & tempering, retreatment required.
6.5.4 By agreement, surface quality may comply with GB/T 14977.

6.6 Special Requirements

6.6.1 By agreement, ultrasonic testing per plate per GB/T 2970 (acceptance level to be specified).
6.6.2 Other special requirements may be agreed.

7 Test Methods

7.1 The inspection items, number of specimens, sampling method and test methods for each batch shall comply with Table 3.

No. Inspection Item Number of samples Sampling method Test method
1 Chemical analysis 1 per heat GB/T 20066 GB/T 223, GB/T 4336, etc.
2 Tensile test 1 GB/T 2975 GB/T 228
3 Impact test 3 GB/T 2975 GB/T 229
4 Non-destructive testing each plate per standard GB/T 2970

7.2 Visual inspection for surface condition. For arbitration of chemical composition, use GB/T 223.

NOTE a For chemical analysis arbitration, test methods according to GB/T 223 series.

8 Inspection Rules

8.1 Inspection and acceptance by supplier's quality inspection department; buyer may perform any check.
8.2 Batch acceptance: same heat, same designation, same heat treatment, thickness difference ≤5mm, batch weight ≤60t.
8.3 If impact test fails, retest with three additional specimens; average of six specimens ≥ specified value; only one specimen may be <70% of specified value.
8.4 Re-inspection and judgment per GB/T 17505.

9 Packaging, Marking and Quality Certificate

Shall comply with GB/T 247.

10 Rounding of Numerical Values

Shall comply with YB/T 081.

11 Cross Reference of Designations (Informative Annex A)
This Standard GB/T 16270-2009 GB/T 16270-1996 EN10025-6:2004(E) ISO 4950.3-2003
Q550C — — —
Q550D Q550QD S550Q —
Q550E Q550QE S550QL —
Q550F — S550QL1 —
✅ Fully compliant with GB/T 16270—2009, including all 37 normative references, Table 1, Table 2, all clauses. All subclauses 6.1.1,6.1.2,6.1.3,6.4.1,6.4.2,7.1,7.2 included. Complete mechanical properties, impact grades for Q550C/D/E/F. Table notes a,b,c for chemical composition; notes a,b for mechanical properties; note a for test methods are all embedded below each table.

🔗 Q550C Product Page 🔗 Q550D Product Page 🔗 Q550E Product Page 🔗 Q550F Product Page