Q355NE High Strength Low Alloy Structural Steel

Normalized (N)   Grade E    -40°C Impact (27J)    Min Yield 355MPa

This standard specifies the designation system, ordering information, dimensions, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of high strength low alloy structural steels.

It is applicable to steel plates, strips, sections, bars, etc. for general structures and engineering purposes. The chemical composition requirements are also applicable to steel billets.

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.

GB/T 222 - Permissible deviations for chemical composition of steel products
GB/T 223.3 - Determination of phosphorus by diantipyrylmethane phosphomolybdic acid gravimetric method
GB/T 223.9 - Determination of aluminum content - Chrome azurol S spectrophotometric method
GB/T 223.11 - Determination of chromium content - Visual titration or potentiometric titration method
GB/T 223.14 - Determination of tantalum content - Tantalum reagent extraction photometric method
GB/T 223.17 - Determination of titanium content - Diantipyrylmethane photometric method
GB/T 223.18 - Determination of copper content - Sodium thiosulfate separation-iodometric method
GB/T 223.23 - Determination of nickel content - Dimethylglyoxime spectrophotometric method
GB/T 223.26 - Determination of molybdenum content - Thiocyanate spectrophotometric method
GB/T 223.37 - Determination of nitrogen content - Distillation separation-indophenol blue photometric method
GB/T 223.40 - Determination of niobium content - Chlorosulfophenol S spectrophotometric method
GB/T 223.60 - Determination of silicon content - Perchloric acid dehydration gravimetric method
GB/T 223.63 - Determination of manganese content - Sodium periodate (potassium) photometric method
GB/T 223.68 - Determination of sulfur content - Potassium iodate titration method after combustion in tube furnace
GB/T 223.69 - Determination of carbon content - Gas volumetric method after combustion in tube furnace
GB/T 223.76 - Determination of vanadium content - Flame atomic absorption spectrometry method
GB/T 223.78 - Determination of boron content - Curcumin direct photometric method
GB/T 223.79 - Determination of multi-element content - X-ray fluorescence spectrometry (routine method)
GB/T 223.84 - Determination of titanium content - Diantipyrylmethane spectrophotometric method
GB/T 228.1 - Tensile testing - Part 1: Room temperature test method
GB/T 229 - Charpy pendulum impact test method
GB/T 232 - Bending test method
GB/T 247 - General rule of packaging, marking and quality certificate for plates and strips
GB/T 702 - Dimensions, shape, weight and tolerances for hot rolled steel bars
GB/T 706 - Hot rolled sections
GB/T 709 - Dimensions, shape, weight and tolerances for hot rolled plates and strips
GB/T 2101 - General rule of acceptance, packaging, marking and quality certificate for sections
GB/T 2975 - Sampling location and specimen preparation for mechanical properties testing
GB/T 4336 - Determination of multi-element content - Spark discharge atomic emission spectrometry (routine method)
GB/T 5313 - Steel plates with through-thickness properties
GB/T 8170 - Rules of rounding off for numerical values and judgement of limiting values
GB/T 11263 - Hot rolled H-beams and split T-beams
GB/T 14977 - General requirements for surface quality of hot rolled plates
GB/T 17505 - General technical delivery requirements for steel and steel products
GB/T 20066 - Sampling and sample preparation for determination of chemical composition
GB/T 20123 - Determination of total carbon and sulfur - High frequency induction furnace combustion infrared absorption method (routine method)
GB/T 20124 - Determination of nitrogen - Inert gas fusion thermal conductivity method (routine method)
GB/T 20125 - Determination of multi-element content - Inductively coupled plasma atomic emission spectrometry
GB/T 28300 - Surface quality grade delivery technical conditions for hot rolled bars and wire rods
YB/T 4427 - General requirements for surface quality of hot rolled sections

3.1 Hot rolled as-rolled AR or WAR
Steel without any special rolling and/or heat treatment.

3.2 Normalized N
Heat treatment process where steel is heated to a suitable temperature above transformation point and then cooled in air to a temperature below a transformation point.

3.3 Normalized rolling +N
Rolling process where final deformation is carried out within a certain temperature range to achieve a condition equivalent to normalized, so that the specified mechanical properties can be achieved even after normalizing.

Note: For normalized rolling, it is also called "controlled rolling" in some publications.

3.4 Thermomechanical processed M
Rolling process where final deformation is carried out within a certain temperature range to achieve properties that cannot be obtained by heat treatment alone.

Note 1: Hot forming that may reduce strength or post-weld heat treatment above 580°C is not suitable. Flame straightening is permitted according to relevant technical specifications.

Note 2: Thermomechanical processing may include accelerated cooling with or without tempering (including self-tempering but excluding direct quenching and quenching plus tempering).

Note 3: Also known as TMCP (Thermo-Mechanical Control Process) or "controlled rolling" in some publications.

4.1 The steel designation consists of four parts: the Chinese pinyin initial letter "Q" representing yield strength, the specified minimum upper yield strength value, the delivery condition code, and the quality grade symbol (B, C, D, E, F).

Note 1: For hot rolled condition, the delivery condition code AR or WAR may be omitted; for normalized or normalized rolled condition, the delivery condition code N is used.

Note 2: Q + specified minimum upper yield strength value + delivery condition code is referred to as "steel grade".

Example: Q355NE. Where: Q = yield strength, 355 = specified minimum yield value (MPa), N = normalized/normalized rolling, E = quality grade E.

4.2 When the purchaser requires through-thickness property for plates, the symbol representing the thickness direction (Z-direction) performance level shall be added after the designation, such as Q355NEZ25.

5.1 The contract or order shall include the following:

a) Standard number;
b) Product type;
c) Steel designation (steel grade + quality grade);
d) Dimensions, shape and tolerances (see Clause 6);
e) Delivery weight (or quantity);
f) All required optional contents (see 5.2).

5.2 By agreement between the supplier and purchaser, and specified in the contract, the following optional contents may be selected. If not specified by the purchaser in the inquiry and order, the product shall be supplied according to 5.1.

a) Carbon equivalent or welding crack sensitivity index (Pcm) (see 7.1.3, Table 6);
b) Alloying elements and their content (see 7.1.6, Table 1, Table 3, Table 5);
c) Lower limit of chemical composition for commercial steel billets (see 7.1.8);
d) Product analysis (see 7.1.9);
e) Steelmaking method (see 7.2);
f) Impact test temperature and impact test sampling direction (see Table 11);
g) Bending test (see 7.4.3);
h) Through-thickness property (Z-direction) (see 7.1.7, 7.4.1.4 and 9.2.3);
i) Surface quality (see 7.5.1.5, 7.5.2.4, 7.5.3.2, 7.5.4.2);
j) Non-destructive testing (see 7.6);
k) Impact specimen sampling location (see 8.3).

6.1 Hot rolled steel bars: according to GB/T 702, specific group shall be specified in contract.

6.2 Hot rolled sections: according to GB/T 706, specific group shall be specified in contract.

6.3 Hot rolled plates and strips: according to GB/T 709, specific precision class shall be specified in contract.

6.4 Hot rolled H-beams and split T-beams: according to GB/T 11263.

6.5 Other dimensions, shape and tolerances may be supplied by agreement.

7.1.1 Hot rolled steel: chemical composition per Table 1, carbon equivalent per Table 2.

7.1.2 Normalized and normalized rolled steel: chemical composition per Table 3, carbon equivalent per Table 4.

7.1.3 TMCP steel: chemical composition per Table 5, carbon equivalent per Table 6. When C ≤0.12%, Pcm (welding crack sensitivity index) is recommended instead of CEV to evaluate weldability.

7.1.4 Carbon equivalent (CEV) and welding crack sensitivity index (Pcm) formulas:

CEV(%) = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

Pcm(%) = C + Si/30 + Mn/20 + Cu/20 + Ni/60 + Cr/20 + Mo/15 + V/10 + 5B

7.1.5 Nitrogen content analysis may be omitted if guaranteed by supplier.

7.1.6 To improve properties, alloying elements (Nb, V, Ti) may be added by agreement. Alloy content shall be stated in quality certificate.

7.1.7 When Z-direction property required, sulfur content shall comply with GB/T 5313.

7.1.8 For commercial steel billets, lower limit of chemical composition may be agreed.

7.1.9 Product analysis tolerance according to GB/T 222.

7.1.10 International grade comparison see Appendix A.

^a Microalloying elements (Nb, V, Ti) may be added by agreement. Total microalloy content ≤0.22%.

^b For normalized steel: fine grain elements Al ≥0.015%, Nb+V+Ti ≤0.22%.

^c For TMCP steel: Nb ≤0.09%, V ≤0.10%, Ti ≤0.06%.

^d Nitrogen analysis may be omitted if guaranteed.

^e Product analysis tolerance per GB/T 222.

^f For steel billets, lower limits may be agreed.

^g For Z-direction, sulfur content per GB/T 5313 (≤0.010% for Z35).

7.2 Steel shall be made by converter or electric furnace, with optional ladle refining. Unless specified, method is at supplier's discretion.

7.3 Q355NE is supplied in Normalized (N) or Normalized Rolling (N) condition. Normalized condition includes normalized + tempering.

7.5.1 Plates

7.5.1.1 No blisters, scabs, cracks, folds, inclusions or rolled-in scale. No visible laminations.

7.5.1.2 Thin scale, rust, pits, scratches allowed if within tolerance.

7.5.1.3 Defects may be removed by grinding within negative tolerance.

7.5.1.4 Welding repair permitted by agreement:

a) Appropriate welding methods;
b) Defects completely removed before repair, depth ≤20% of nominal thickness, area ≤2%;
c) No undercut or overlap, built-up height >1.5mm then ground flat;
d) Heat-treated plates shall be heat treated again after repair.

7.5.1.5 By agreement, surface quality may also comply with GB/T 14977.

7.5.2 Strips and sheared plates

7.5.2.1 No harmful defects. No visible laminations.

7.5.2.2 Thin scale, rust, pits, scratches allowed within tolerance.

7.5.2.3 Defective part ≤6% of coil length.

7.5.2.4 By agreement, may comply with GB/T 14977.

7.5.3 Sections

7.5.3.1 Surface quality shall comply with relevant standards.

7.5.3.2 By agreement, may comply with YB/T 4427.

7.5.4 Bars

7.5.4.1 Surface quality shall comply with relevant standards.

7.5.4.2 By agreement, may comply with GB/T 28300.

By agreement between supplier and purchaser, non-destructive testing may be used to inspect internal quality; testing standards and requirements shall be specified in contract.

8.1 The inspection items, sampling quantity, sampling methods and test methods for each inspection of steel shall comply with Table 13.

8.2 Chemical composition test of steel shall generally be carried out according to GB/T 4336, GB/T 20123, GB/T 20124, GB/T 20125 or general chemical analysis methods. For arbitration, it shall be carried out according to GB/T 223.3, GB/T 223.9, GB/T 223.11, GB/T 223.14, GB/T 223.17, GB/T 223.18, GB/T 223.23, GB/T 223.26, GB/T 223.37, GB/T 223.40, GB/T 223.60, GB/T 223.63, GB/T 223.68, GB/T 223.69, GB/T 223.76, GB/T 223.78, GB/T 223.84 and GB/T 20125.

8.3 When there is no special requirement from the purchaser, the sampling location for impact test shall be as follows:

a) For sections, according to GB/T 2975-2018 Figure A.3;
b) For round bars, when nominal diameter d≤25mm, 25mm<d≤50mm, and d>50mm, according to GB/T 2975-2018 Figure A.5 a), b), d) respectively;
c) For square bars, when side length ≤50mm, according to GB/T 2975-2018 Figure A.9 a); when side length >50mm, according to GB/T 2975-2018 Figure A.9 b);
d) For plates, when nominal thickness ≤40mm, according to GB/T 2975-2018 Figure A.11 a); when nominal thickness >40mm, according to GB/T 2975-2018 Figure A.11 b).

9.1 Inspection and Acceptance - Carried out by supplier's technical supervision department.

9.2 Lot Formation Rules

9.2.1 Each lot: same grade, heat, specification, delivery condition. Max 60 tons (80 tons for sections from >200t converters). Coils >30t may form two coils per lot.

9.2.2 For Q355B mixed lot: max 6 heats, C difference ≤0.02%, Mn difference ≤0.15%.

9.2.3 For Z-direction: lot formation per GB/T 5313.

9.3 Sampling Quantity - Per Table 13.

9.4 Retest and Judgment Rules - Per GB/T 17505.

9.5 Numerical Rounding - Per GB/T 8170 (rounding-off comparison method).

Unless otherwise specified, packaging, marking and quality certificate shall comply with GB/T 247 for plates/strips or GB/T 2101 for sections.

Note: Q355NE replaces Q345E normalized grade with improved mechanical properties (increased by 10-15 MPa). EN 10025-3 S355NL is the European equivalent for normalized fine grain structural steel with low temperature impact (-40°C to -50°C).

© 2025 Cehe Steel · Data based on GB/T 1591-2018 · Q355NE Technical Data Sheet · For reference only

Product Page: Q355NE Grade Comparison