GBT 1591-2008

7/18/2019 GBT 1591-2008

http://slidepdf.com/reader/full/gbt-1591-2008 1/17

ICS 77.140.10; 77.140.50

H 46

NATIONAL STANDARD OF THE PEOPLE’S REPPUBLIC OF CHINA

华民共和国国家标准

GB/T 1591-2008

Replace GB/T 1591-1994

High Strength Low Alloy Structural Steels

低合金高强度结构钢

Issued on December 6, 2008 Implemented on October 1, 2009

Jointly issued by General Administration of Quality Supervision, Inspection and

Quarantine of the People's Republic of China and

Standardization Administration of China

7/18/2019 GBT 1591-2008


Contents

1. Scope ..................................................................................................................................... 1

2. Normative References ........................................................................................................... 1

3. Terms and Definitions ........................................................................................................... 2

4. Grade Representation ............................................................................................................ 35. Dimension, Shape, Weight and Allowable Deviation .................................... ....................... 3

6. Technical Requirements ........................................................................................................ 3

7. Test Method ......................................................................................................................... 13

8. Test Rules ............................................................................................................................ 13

9. Packaging, Mark and Quality Certificate ............................................................................ 14

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Foreword

The standard GB/T 1591-1994 "High Strength Low Alloy Structural Steels" is revised in

accordance with EN 10025: 2004 "Structural Steel Hot Rolled Products".

This standard replaces GB/T 1591-1994 "High Strength Low Alloy Structural Steels".

There have been some significant changes in this standard over GB/T 1591-1994 in thefollowing technical aspects:

——application range of the standard is expanded;

——graded intensity scales of the Q500, Q550, Q620 and Q690 are added; and graded

intensity scale of Q295 is cancelled;

——the requirements of the chemical composition of the steel products are modified;

and such harmful elements as phosphorus and sulfur are controlled more strictly;

——calculation formula and requirements of the carbon equivalent and crack sensitivity

coefficient of the steel products are added;

——delivery state of the steel products is modified; and the requirements of the

quenched and tempered steel are cancelled;

——the requirements for mechanical properties and thickness class width of the steel

products are modified; and lower yield strength is determined to the yield strength;

——impact absorption energy value is improved;

——requirements for the thickness directional property of all graded steels are added.

This standard is proposed by China Iron & Steel Association.

This standard is under jurisdiction of China Steel Standardization Technical Committee.

Drafting organizations: Angang Steel Co., Ltd.; China Metallurgical Information

Standardization Research Institute; Jigang Group Co., Ltd.; Shougang Group; Jiangsu

Shagang Group Co., Ltd. and Hunan Hualing Lianyuan Steel Co., Ltd.

Chief drafting staff: LIU Xuyuan, PU Zhimin, WANG Xiaohu, GAO Ling, WANG

Liping, HUANG Zhengyu, ZHOU Jian, MA Yupu and CHEN Shuqin.This standard replaces the previous versions:

——GB 1591-1979, GB 1591-1988 and GB/T 1591-1994.

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High Strength Low Alloy Structural Steels

1. Scope

This standard specifies grade, dimension, shape, weight, allowable deviation, technical

requirements, test methods, test rules, packaging, mark and quality certificate.

This standard is applicable to the steel plate, steel strip, section steel and steel bar of the high

strength low alloy structural steels which are with general structure or is used for the

engineering. 2. Normative References

The following standards contain provisions which, through reference in this text,

constitute provisions of this standard. For date reference, the subsequent amendments to

(excluding amending error in the text) or revisions of, any of these publications do not apply.

And parties to agreements based on this standard are encouraged to investigate the possibility

of applying the most recent editions of the standards indicated below. For undated references,

its latest edition referred to applies.

GB/T 222 Allowable Deviation of Steel Product Analysis

GB/T 223.5 Iron and steel: reduced silicate spectrophotometric method for the

determination of the acid soluble silicon and all silicon content

GB/T 223.9 Steel and alloy: the chrome azurol S spectrophotometric method for the

determination of aluminum content;

GB/T 223.12 Chemical analysis method for steel and alloy: the sodium carbonate

separation-diphenyl carbazide photometric method for the determination of chromium contentGB/T 223.14 Chemical analysis method for steel and alloy: the

N-benzoy-N-phenylhydroxylamine extraction photometric method for the determination of

vanadium content

GB/T 223.16 Chemical analysis method for steel and alloy: the chromotropic acid

photometric method for the determination of titanium content

GB/T 223.19 Chemical analysis method for steel and alloy: the neocuproine-chloroform

extraction photometric method for the determination of copper content

GB/T 223.23 Steel and alloy: the dimethylglyoxime spectrophotometric method for the

determination of nickel content

GB/T 223.26 Steel and alloy: the thiocyanate spectrophotometric method for the

determination of molybdenum content

GB/T 223. 37 Chemical analysis method for steel and alloy: the indophenol blue

photometric method for the determination of nitrogen content after distillation separation;

GB/T 223. 40 Steel and alloy: the chlorsulphophenol S spectrophotometric method for

the determination of niobium content;

GB/T 223. 62 GB/T 223.62 Chemical analysis method for steel and alloy: phosphorus

quantity measured according to butyl acetate extraction-photometric method;

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GB/T 223. 63 Chemical analysis method for steel and alloy: the sodium (potassium)

periodate photometric method for the determination of manganese content

GB/T 223. 67 Iron and steel and alloy: the methylene blue spectrophotometric method

for the determination of sulfur content

GB/T 223. 69 Iron and steel and alloy: the gas-volumetric method after combustion in

the pipe furnace for the determination of carbon contentGB/T 223. 78 Chemical analysis method for steel and alloy: curcumin direct photometric

method for the determination of boron content

GB/T 228 Metallic Materials-Tensile Testing at Ambient Temperature (GB/T 228-2002,

eqv ISO 6892:1998)

GB/T 229 Metal material- Charpy pendulum impact test (GB/T 229-2007, ISO 148-1:

2006, MOD)

GB/T 232 Metal materials: bending test method (GB/T 232-1999, eqv ISO 7438:1985)

GB/T 247 General rule of acceptance, package, mark and certification for steel plates

(sheets) and steel strips

GB/T 2101 General Rule of Acceptance, Package, Mark and Certification for Section

Steel

GB/T 2975 Steel and Steel Products-Mechanical Testing for Sampling Location and

Specimen Preparation (GB/T 2975-1998, eqv ISO 377: 1997)

GB/T 4336 Method for Photoelectric Emission Spectroscopic Analysis of Carbon Steel

and Medium and Low Alloy Steel (conventional)

GB/T 5313 Through-thickness property steel plate (GB/T 5313-1985, eqv ISO

7778:1983)

GB/T 17505 Steel and steel products: general technical delivery requirements (GB/T

17505-1998, eqv ISO 404: 1992)

GB/T 20066 Steel and iron-sampling and preparation of samples for the determination of

chemical composition (GB/T 20066-2006, 150 14284:1996, IDT)GB/T 20125 Low alloy steel-inductively coupled plasma emission spectrometer for the

determination of multielement content

YB/T 081 Rule for rounding off of numberical values and judgment of testing values for

technical standards of metallurgy

3. Terms and Definitions

3.1 Thermomechanical rolling

The ultimate deformation is a rolling procedure, which is carried out within a certaintemperature range. This procedure makes the material obtain the special performance which is

not obtained only through heat treatment.

Note 1: If the temperature is increased to 580℃ after the rolling, the material strength value may be reduced. If it is

necessary to increase the temperature to 580℃, it shall be supplied by the seller.

Note 2: Thermomechanical rolling delivery state may contain accelerated cooling or accelerated cooling plus tempering

(contain self tempering), but excludes direct quenching or quenching plus tempering.

3.2 Normalizing rolling

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The ultimate formation is a rolling procedure, which is carried out within a certain

temperature range. This procedure makes the material obtain the performance which is

equivalent to that after the normalizing.

4. Grade Representation

Steel grade is composed of such three parts as Chinese phonetic alphabet and numerical

value of the yield strength and quality classification. For instance, Q345D; thereinto:

Q——is the first letter of the Chinese phonetic alphabet of the word "Qu" of the steel

yield strength;

345——is the numerical value of the yield strength (MPa);

D——is the quality classification; D grade.

When the steel plate shall be of through-thickness property which is required by the

buyer, the symbol which stands for the grade of the through-thickness (Z direction) property

shall be added based on the aforesaid specified grade; for instance: Q345DZ15.

5. Dimension, Shape, Weight and Allowable Deviation

Dimension, shape, weight and allowable deviation shall meet the requirements of the

corresponding standard.

6. Technical Requirements

6.1 Grade and Chemical Composition

6.1.1 Steel grade and chemical composition (heat analysis) shall meet the requirements of

Table 1.

6.1.2 When the refined grain elements are needed to be added, there shall be at least one of

such four elements as Al, Nb, V and Ti. The content of the added refined grain elements shall

be marked in the quality certificate.

6.1.3 When it is expressed through the all-aluminum (Al t) content, Alt shall not be less than

0.020%.

6.1.4 The content of nitrogen element in the steel shall meet the requirements of Table 1. If it

is determined by the seller, nitrogen element content may not be analyzed. If such alloy

element (it is of nitrogen fixation) as Al, Nb, V and Ti are added into the steel, the nitrogen

element content is not be restricted. The content of the nitrogen fixation element shall be

marked in the quality certificate.

6.1.5 When Cr, Ni and Cu of each grade are taken as residual elements, their contents are not

larger than 0.03% respectively. If it is determined by the seller, it may not be analyzed; when

it needs to be added, the content shall meet the requirements of Table 1 or shall be agreed by

the buyer and the seller.

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6.1.6 To improve the performance of the steel, TE element may be added. And its addition

shall be calculated according to 0.02% - 0.02% of the weight of liquid steel.

6.1.7 The mechanical properties of the steel products shall meet the requirements of the

standard. Based on this, the delivered terms may not be done for the chemical composition of

C, Si and Mn of grade A for each grade.

Table 1

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GradeQuality

grade

Chemical composition s, b (mass fraction)/%

C Si Mn

P S Nb V Ti Cr Ni C

Not larger than

Q345

A

≤0.20

≤0.50 ≤1.70

0.035 0.035

0.07 0.15 0.20 0.30 0.50 0

B 0.035 0.035

C 0.030 0.030

D≤0.18

0.030 0.025

E 0.025 0.020

Q390

A

≤0.20 ≤0.50 ≤1.70

0.035 0.035

0.07 0.20 0.20 0.30 0.50 0

B 0.035 0.035

C 0.030 0.030

D 0.030 0.025

E 0.025 0.020

Q420

A

≤0.20 ≤0.50 ≤1.70

0.035 0.035

0.07 0.20 0.20 0.30 0.80 0

B 0.035 0.035

C 0.030 0.030

D 0.030 0.025

E 0.025 0.020

Q460

C

≤0.20 ≤0.60 ≤1.80

0.030 0.030

0.11 0.20 0.20 0.30 0.80 0D 0.030 0.025

E 0.025 0.020

Q500

C

≤0.18 ≤0.60 ≤1.80

0.030 0.030

0.11 0.12 0.20 0.60 0.80 0D 0.030 0.025

E 0.025 0.020

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(Continued)

GradeQuality

grade

Chemical composition s, b (Mass fraction)/%

C Si Mn

P S Nb V Ti Cr Ni Cu

No larger than

Q550

C

≤0.18 ≤0.60 ≤2.00

0.030 0.030

0.11 0.12 0.20 0.80 0.80 0.80 D 0.030 0.025

E 0.025 0.020

Q620

C

≤0.18 ≤0.60 ≤2.00

0.030 0.030

0.11 0.12 0.20 1.00 0.80 0.80 D 0.030 0.025

E 0.025 0.020

Q690

C

≤0.18 ≤0.60 ≤2.00

0.030 0.030

0.11 0.12 0.20 1.00 0.80 0.80 D 0.030 0.025

E 0.025 0.020

a The content of P and S of the sectional bar and steel bar may rise by 0.005%; and the upper limit of grade A steel may be 0.045%.

b When the combination of the refined grain element is added, 20 (Nb+V+Ti)≤0.22%，20 (Mo+Cr)≤0.30%.

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6.1.8 As for all grades of steels (excluding Grade A steel), when they are delivered at hot

rolling or controlled rolling state, the maximum carbon equivalent value shall meet the

provisions of Table 2; when they are delivered at normalizing, normalizing rolling or

normalizing and tempering state, the maximum carbon equivalent value shall meet the

provisions of Table 3; when they are delivered at thermomechanical rolling (TMCP) or

thermomechanical rolling and tempering state, the maximum carbon equivalent value shallmeet the provisions of Table 4. The carbon equivalent value (CEV) shall be calculated

according to Formula (1) on the basis of heat analysis compositions.

CEV=C+Mn/6+ (Cr +Mo +V)/5+ (Ni +Cu)/15 (1)

Table 2 Carbon Equivalent Value of Steels Delivered at Hot-rolling, Controlled-rolling State

GradeCarbon equivalent value (CEV)/%

Normal thickness or diameter ≤63 mm Normal thickness or diameter>63 mm-250 mm Normal thickness>250 mm

Q345 ≤0.44 ≤0.47 ≤0.47

Q390 ≤0.45 ≤0.48 ≤0.48

Q420 ≤0.45 ≤0.48 ≤0.48

Q460 ≤0.46 ≤0.49 —

Table 3 Carbon Equivalent Value of Steels Delivered at Normalizing, Normalizing Rolling or Normalizing +

Tempering State

Grade

Carbon equivalent value (CEV)/%

Normal thickness≤63 mm Normal thickness or diameter>63 mm - 120 mm Normal thickness>120mm

- 250 mm

Q345 ≤0.44 ≤0.48 ≤0.48

Q390 ≤0.46 ≤0.48 ≤0.49

Q420 ≤0.48 ≤0.50 ≤0.52

Q460 ≤0.53 ≤0.54 ≤0.55

Table 4 Carbon Equivalent Value of Steels Delivered at Thermomechanical Rolling (TMCP) or

Thermomechanical Rolling + Tempering State

Grade

Carbon equivalent value (CEV)/%

Normal thickness≤63 mm Normal thickness or diameter>63 mm - 120 mm Normal thickness>120mm

- 150 mm

Q345 ≤0.44 ≤0.48 ≤0.48

Q390 ≤0.46 ≤0.48 ≤0.49

Q420 ≤0.48 ≤0.50 ≤0.52

Q460 ≤0.53 ≤0.54 ≤0.55

Q500 ≤0.47 ≤0.48 ≤0.48

Q550 ≤0.47 ≤0.48 ≤0.48

Q620 ≤0.48 ≤0.49 ≤0.49

Q690 ≤0.49 ≤0.49 ≤0.49

6.1.9 When the carbon content of steels delivered at thermomechanical rolling (TMCP) or

thermomechanical rolling + tempering state is no bigger than 0.12%, the solderability of

steels may be evaluated by the welding crack sensitivity index (Pcm) in place of carbon

equivalent value. Pcm shall be calculated according to Formula (2) on the basis of the heat

analysis compositions and its value shall meet the provisions of Table 5.

Pcm=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/1S+V/10+5B (2)

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According to the negotiation between both buyer and seller, the carbon equivalent value

or welding crack sensitivity index may be specified for evaluating the solderability of steel. In

case that it is unspecified, the seller may choose any one of them.

Table 4 Pcm Value of Steels Delivered at Thermomechanical Rolling (TMCP) or Thermomechanical Rolling

+ Tempering State

Grade Pcm/%Q345 ≤0.20

Q390 ≤0.20

Q420 ≤0.20

Q460 ≤0.20

Q500 ≤0.25

Q550 ≤0.25

Q620 ≤0.25

Q690 ≤0.25

6.1.10 The allowable deviation of chemical composition for the steels and billets shall meet

the provisions of GB/T 222.6.1.11 If the buyer requires steel plates with through-thickness characteristics, the chemical

composition of the steel plates shall meet the provisions of GB/T 5313.

6.2 Smelting Process

The steel is smelted by converters or electric furnaces, and if necessary, out-of-furnace

refining can be adopted as well.

6.3 Condition of Delivery

The steels shall be delivered at hot rolling/controlled rolling/normalizing/normalizing

rolling/normalizing + tempering/thermomechanical rolling (TMCP) or thermomechanical

rolling + tempering state.

6.4 Mechanical Properties and Processing Properties

6.4.1 Tensile testing

The tensile testing property of steels shall meet the provisions of Table 6.

6.4.2 Charpy (V-type) impact test

6.4.2.1 The test temperature and impact absorbtion energy of the Charpy (V-type) impact test

shall meet the provisions of Table 7.

6.4.2.2 The impact test shall be conducted for steels whose thickness is not less than 6mm or

diameter not less than 12mm. The dimension of impact specimen shall be 10mm×10mm×

55mm; when there aren’t enough steels for preparing standard specimen, mini-sized specimen

whose dimension is 10mm× 7.5mm× 55mmor 10mm× 5mm×55mm shall be adopted, and the

impact absorbtion energy shall not be less than 75% or 50% of the specified value in Table 7

respectively. Larger-sized specimen shall be adopted in preference.6.4.2.3 The result of impact test for steels shall be the arithmetic mean value of three

specimens (consisting of a group). It is allowed that one of the test values is lower than the

specified value but it shall not be lower than 70% of the specified value; otherwise, it is

required to test three other specimens from the same sampled steels and the arithmetic mean

value of the six specimens shall not be lower than the specified value. It is allowed that the

test results of any two specimens are lower than the specified value; however, only one test

result is allowed to be lower than 70% of the specified value.

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6.4.3 The reduction of area of through-thickness of Z-direction steels shall meet the

provisions of GB/T 5313.

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Table 6 Tensile Property of Steels

Gr

de

Qua

lity

grad

e

Tensile testing a, b, c

Yield strength under the following normal thickness (diameter, side length) (R eL)/Mpa Tensile strength under the following normal thickness (diameter, sidelength) (R eL)/Mpa

≤16

mm

>16~4

0mm

>40~6

3mm

>63~8

0mm

>80~10

0mm

>100~1

50mm

>150~2

00mm

>200~2

50mm

>250~4

00mm

≤40

mm

>40~6

3mm

>63~8

0mm

>80~10

0mm

>100~1

50mm

>150~2

50mm

>250~4

00mm

Q3

5

A

≥34

5≥335 ≥325 ≥315 ≥305 ≥285 ≥275 ≥265

-470-

630

470-6

30

470-6

30

470-63

0

450-

600

450-

600

-B

C

D≥265 450-60

E

Q3

0

A

≥39

0≥370 ≥350 ≥330 ≥330 ≥310 - - -

490-

650

490-6

50

490-6

50

490-65

0470-620 - -

B

C

D

E

Q4

0

A

≥42

0≥400 ≥380 ≥360 ≥360 ≥340 - - -

520-

680

520-6

80

520-6

80

520-68

0500-650 - -

B

C

D

E

Q4

0

C

≥46

0≥440 ≥420 ≥400 ≥400 ≥380

-

- -

550-

720

550-7

20

550-7

20

550-72

0530-700 - -

D

E

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Q5

0

C≥50

0≥480 ≥470 ≥450 ≥440 - - - -

610-

770

600-7

60

590-7

50

540-73

0- - -D

E

Q5

0

C≥55

0≥530 ≥520 ≥500 ≥490 - - - -

670-

830

620-8

10

600-7

90

590-78

0- - -D

E

Q6

0

C≥62

0≥600 ≥590 ≥570

710-

880

690-8

80

670-8

60- - - -D

E

Q6

0

C≥69

0≥670 ≥660 ≥640

770-

940

750-9

20

730-9

00- - - -D

E

When the yield is not obvious, the R p0.2

value may be measured in place of the lower yield strength.

As for the flat steels whose width is not less than 600mm, transverse specimen shall be adopted for tensile testing; while for flat steels, sections and steel bars whose width is less than

alue of post-breaking extensibility (absolute value) shall be increased by 1% correspondingly.

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Table 7 Test Temperature and Impact Absorbtion Energy of the Charpy (V-type) Impact Test

Grade Quality grade Test temperature/

Impact absorbtion energy(KV2)a</J

Normal thickness (diameter, side length)

12mm-150mm >150mm-250mm >250mm-400mm

Q345

B 20

≥34 ≥27

-

C 0

D -2027

E -40

Q390

B 20

≥34 - -C 0

D -20

E -40

Q420

B 20

≥34 - -C 0

D -20

E -40

Q460

C 0

≥34

- -

D -20 - -

E -40 - -

Q500,

Q550,

Q620,

Q690

C 0 ≥55 - -

D -20 ≥47 - -

E -40 ≥31 - -

a Longitudinal specimen shall be taken for the impact test.

6.4.4 If bend test is required by the buyer, the test shall meet the provisions of Table 8. If the

seller guarantees that its bending is eligible, then the bend test may not be necessary.

Table 8 Bend Test

Grade Specimen direction

180°bend test

[d=Diameter of bending core, α=Specimen thickness

(diameter)]

Thickness (diameter, side length) of steels

≤16mm >16mm – 100mm

Q345

Q390

Q420

Q460

As for flat steels whose width

is not less than 600mm,

transverse specimen shall be

adopted for the tensile

testing. While for flat steels,

sections and steel bars whose

width is less than 600mm,

longitudinal specimen shall

be adopted.

2α 3 α

6.5 Surface Quality

The surface quality of steels shall meet the provisions of relevant product standards.

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6.6 Special Requirements

6.6.1 According to the agreement of both the buyer and the seller, nondestructive test may be

carried out for steels and its inspection standard and grade shall be indicated in the agreement

or contract.

6.6.2 According to the agreement of both the buyer and the seller, steel plates with

through-thickness characteristics may be ordered according to this standard.6.6.3 According to the agreement of both the buyer and the seller, other inspection may also

be adopted for the steels.

7. Test Method

The testing items, sampling quantity, sampling methods and test methods for each test of

the steels shall meet the provisions of Table 9.

Table 9 Testing Items, Sampling Quantity, Sampling Methods and Test Methods for Each Test of the Steels

Serial

NumberTesting items Sampling quantity/pcs Sampling method Test method

1Chemical composition

(heat analysis)1/furnace GB/T 20066

GB/T 223, GB/T 4336,

GB/T 20125

2 Tensile testing 1/batch GB/T 2975 GB/T 228

3 Bend test 1/batch GB/T 2975 GB/T 232

4 Impact test 3/batch GB/T 2975 GB/T 229

5

Reduction of area of

through-thickness

Z-direction steels

3/batch GB/T 5313 GB/T 5313

6 Nondestructive testSheet by sheet or piece by

piece

According to the

provisions of

nondestructive test

standard

Negotiation

7 Surface quality Sheet by sheet / piece by piece - Visual measurement

8 Dimension and shape Sheet by sheet / piece by piece -Appropriate measuring

device

8. Test Rules

8.1 Check and Acceptance Inspection

The check and acceptance of steels shall be carried out by the seller, and the buyer is

entitled to check and inspect any of the testing items specified in this standard or contract.

8.2 batch rules

The steels shall be accepted in batches. Each batch of steels are composed of steels of the

same grade, the same quality grade, the same furnace number, the same specification, the

same rolling schedule or the same heat treatment system and the weight of each batch shall be

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no bigger than 60t. The batch weight of steel strips shall meet the provisions of corresponding

product standard.

As for the Class A steel or Class B steel, they can be batched according to the same grade,

the same quality grade, the same smelting and grouting method but with different furnace

number. However, there shall be no more than six furnace number in each batch, and the

difference of C content of each furnace shall not be greater than 0.02%, while the differenceof Mn content shall not be greater than 0.15%.

The Z-direction steels shall be batched in accordance with the provisions of GB/T 5313.

8.3 Recheck and Decision Rules

8.3.1 Recheck and determination of mechanical properties

When the impact test result of steels doesn't meet the provisions of 6.4.2.3, the sampled

steels shall not be accepted. Take another two products from the remained test part and

sample three new specimens (consisting one group). The test results of the two groups of

specimen shall be eligible both, otherwise the batch of steels shall be rejected. The recheck

and determination of steels' tensile testing shall meet the requirements of GB/T 17505.

8.3.2 Recheck and determination of other testing items

The recheck and determination of steels' other testing items shall meet the requirements

of GB/T 17505.

8.4 Rounding-off of the Test Results of Mechanical Properties and Chemical

Composition

Unless otherwise stated in the contract or order sheet, when it is necessary to evaluate

whether the test result can meet the specified value or not, the given test result of mechanical

properties and chemical composition shall be rounded off in accordance with the specified

value. The rounding-off method shall be carried out according to the provisions of YB/T 081.

The carbon equivalent value shall be rounded off after being calculated according to the

formula.

9. Packaging, Mark and Quality Certificate

The packaging, mark and quality certificate of the steels shall meet the provisions of

GB/T 247 and GB/T 2101.

Documents

GBT 1591-2008