16-GB-T 8162-1999-Seamless Steel Tubes for Structural Purposes

GB ICS 77.140.75

H 48

National Standard of the People's Republic of China

中华人民共和国国家标准

GB/T 8162-2008

Replace GB/T 8162-1999

Seamless Steel Tubes for Structural Purposes

结构用无缝钢管

Issued on August 19, 2008 Implemented on April 1, 2009

Jointly issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and Standardization Administration Of The People's Republic of China.

Forwards

This national standard is not equivalent to EN 10297-1: 2003 "Seamless Circular Steel

Tubes for Mechanical and General Engineering Purposes-Technical Delivery Conditions".

This national standard replaces GB/T 8162-1999 "Seamless Steel Tubes for Structural

Purposes", while comparing with it, this Standard has the following major variation:

——add order content;

——modify allowable deviation of the dimension;

——add requirements of the full-length tortuosity factor;

——add requirements of the terminal shear drag;

——cancel marking illustrations;

——add steel grades;

——cancel requirements of the expanding test;

——add negotiation provisions of the nondestructive test

This national standard is proposed by China Iron & Steel Association.

This national standard is under jurisdiction of China Steel Standardization Technical

Committee.

This Standard is mainly prepared (organizations) by Angang Steel Company Limited,

Pangang Group Chengdu Iron & Steel Co., Ltd. and Hunan Hengyang Steel Tube Group Co.,

Ltd.

This Standard is mainly prepared by (staffs): ZHANG Huixuan, ZHANG Peng, PIAO

Zhimin, LI Qi, ZHAO Bin and LI Zhi.

This national standard replaces the previous versions:

——GB/T 8162-1987, GB/T 8162-1999

I

II

Contents

Forwards ........................................................................................................................................... I

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

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

3. Order content ................................................................................................................................4

4. Dimension, shape and weight .......................................................................................................4

4.1 Outside diameter and wall thickness...................................................................................4

4.2 Allowable deviation of outside diameter and wall thickness ..............................................4

4.3 Length .................................................................................................................................5

4.4 Tortuosity factor ..................................................................................................................6

4.5 Noncircularity and wall unevenness ...................................................................................6

4.6 Terminal shape ....................................................................................................................6

4.7 Weight .................................................................................................................................7

5. Technical requirements .................................................................................................................7

5.1 Grade of steel and chemical composition ...........................................................................7

5.2 Manufacturing method........................................................................................................8

5.3 Delivery state ......................................................................................................................8

5.4 Mechanical properties .........................................................................................................9

5.5 Technical properties ..........................................................................................................13

5.6 Surface quality ..................................................................................................................13

5.7 Nondestructive test............................................................................................................14

6. Test method .................................................................................................................................14

7. Inspection rules ...........................................................................................................................15

8. Packaging, marking and quality certification..............................................................................15

Seamless Steel Tubes for Structural Purposes

结构用无缝钢管 GB/T 8162-2008

1. Scope

This national standard specifies order content, size, shape, weight, technical requirements,

test methods, test rules, packaging, marking and quality certificate of seamless steel tubes for

structural purposes.

This Standard is applicable to seamless steel tubes for mechanical and general

engineering structural purposes.

2. Normative References

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

constitute provisions of this national Standard. For dated reference, subsequent amendments

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

applied. However, the parties whose enter into agreement according to these specifications are

encouraged to research whether the latest editions of these references are applied or not. For

undated references, the latest edition of the normative document is applicable to this national

standard.

GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products

GB/T 223.3 Methods for Chemical Analysis of Iron, Steel and Alloy; the

Diantipyrylmethane Phosphomolybdate Gravimetric Method for the Determination of

Phosphorus ContentGB/T 223.5 Methods for Chemical Analysis of Iron, Steel and Alloy; the

Reduced Molybdosilicate Spectrophotometric Method for the Determination of Acid-soluble

Silicon Content

GB/T 223.8 Methods for Chemical Analysis of Iron, Steel and Alloy; the Sodium

Fluoride Separation-EDTA Titration Method for the Determination of Aluminium Content

GB/T 223.9 Iron Steel and Alloy-Determination of Aluminium Content-Chrom Azurol S

Photometric Method

GB/T 223.11 Methods for Chemical Analysis of Iron, Steel and Alloy; the Ammonium

Persulfate Oxidation Volumetric Method for the Determination of Chromium Content

GB/T 223.12 Methods for Chemical Analysis of Iron, Steel and Alloy; The Sodium

Carbonate Separation-diphenyl Carbazide Photometric Method for the Determination of

Chromium Content

GB/T 223.13 Methods for Chemical Analysis of Iron, Steel and Alloy; the Ammonium

Ferrous Sulfate Titration Method for the Determination of Vanadium Content


1

N-benzoy-N-phenylhydroxylamine Extraction Photometric Method for the Determination of

Vanadium Content

GB/T 223.16 Methods for Chemical Analysis of Iron, Steel and Alloy; the Chromotropic

Acid Photometric Method for the Determination of Titanium Content


Thiosulfate Separation Iodimetric Method for the Determination of Copper Content

GB/T 223.19 Methods for Chemical Analysis of Iron Steel and Alloy; the

Neocuproine-chloroform Extraction Photometric Method for the Determination of Copper

Content

GB/T 223.23 Iron Steel and Alloy-Determination of Nickel Content; the

Dimethylglyoxime Spectrophotometric Method


Dimethylglyoxime Gravimetric Method for the Determination of Nickel Content

GB/T 223.26 Iron Steel and Alloy-Determination of Molybdenum Content; the

Thiocyanate Spectrophotometric Method

GB/T 223.36 Methods for Chemical Analysis of Iron, Steel and Alloy; the Neutral

Titration Method for the Determinaion of Nitrogen Content after Distillation Separation

GB/T 223.37 Methods for Chemical Analysis of Iron Steel and Alloy; the Indophenal

Blue Photometric Methods for the Determination of Nitrogen Content after Distillation

Separation


Sulphochlorophenol S Photometric Method for the Determination of Niobium Content

GB/T 223.43 Iron Steel and Alloy-Determination of Tungsten Content-Gravimetric

Method and Spectrophotometric Method

GB/T 223.53 Methods for Chemical Analysis of Iron, Steel and Alloy; the Flame Atomic

Absorption Spectrophotometric Method for the Determination of Copper Content


Absorption Spectrophotometric Method for the Determination of Nickel Content


Arsenite-sodium Nitrite Titrimetric Method for the Determination of Manganese Content

GB/T 223.59 Methods for Chemical Analysis of Iron, Steel and Alloy; the Reduced

Molybdoantimonyl Phosphoric Acid Photometric Method for the Determination of

Phosphorus Content

GB/T 223.60 Methods for Chemical Analysis of Iron, Steel and Alloy; the Perchloric

Acid Dehydration Gravimetric Method for the Determination of Silicon Content

GB/T 223.6l Methods for Chemical Analysis of Iron, Steel and Alloy; the Ammonium

Phosphomolybdate Volumetric Method for the Determination of Phosphorus Content

GB/T 223.62 Methods for Chemical Analysis of Iron, Steel and Alloy; the Butyl Acetate

Extraction Photometric Method for the Determination of Phosphorus Content


(Potassium) Periodate Photometric Method for the Determination of Manganese Content

GB/T 223.64 Iron Steel and Alloyed-Determination of Manganese Content-Flame

Atomic Absorption Spectrometric Method


2

Thiocyanate-chlorpromazine Hydrochloride-Chloroform Extraction Photometric Method for

the Determination of Tungsten Content

GB/T 223.67 Iron Steel and Alloy-Determination of Sulfur Content-Methylene Blue

Spectrophotometric Method

GB/T 223.68 Methods for Chemical Analysis of Iron, Steel and Alloy; the Potassium

Iodate Titration Method after Combustion in the Pipe Furnace for the Determination of Sulfur

Content


Gas-Volumetric Method after Combustion in the Pipe Furnace for the Determination of

Carbon Content

GB/T 223.71 Methods for Chemical Analysis of Iron, Steel and Alloy; the Gravimetric

Method after Combustion in the Pipe Furnace for the Determination of Carbon Content

GB/T 223.72 Iron Steel and Alloy-Determination of Sulfur Content-Gravimetric Method

GB/T 223.74 Methods for Chemical Analysis of Iron, Steel and Alloy; the Combustion

Gravimetric/gas-Volumetric Method for the Determination of Combined Carbon Content

GB/T 223.75 Iron Steel and Alloy-Determination of Boron Content-Methanol

Distillation-Curcumin Photometric Method


Absorption Spectrometric Method for the Determination of Vanadium Content

GB/T 223.78 Methods for Chemical Analysis of Iron, Steel and Alloy-Curcumin

Spectrophotometric Method for the Determination of Boron Content (GB/T 223.78-2000, ISO

10153: 1997, IDT)

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

eqv ISO 6892: 1998)

GB/T 229 Metallic Materials—Charpy Pendulum Impact Test Method (GB/T 229-2007,

ISO 148-1: 2006, MOD)

GB/T 231.1 Metallic Materials-Brinell Hardness Test-Part 1: Test Method (GB/T

231.1-2002, ISO 6506-1: 1999, EQV)

GB/T 244 Metallic Materials-Tube-Bend Test (GB/T 244-2008, ISO 8491: 1996, IDT)

GB/T 246 Metal materials—Tube—Flattening test (GB/T 246-2007, ISO 8492: 1998,

IDT)

GB/T 699 Quality Carbon Structural Steels

GB/T 1591 Low-alloy High-tensile Structural Steel

GB/T 2102 Acceptance Packing, Marking and Quality Certification of Steel Pipe

GB/T 2975 Steel and Steel Products--Location and Preparation of Test Pieces for

Mechanical Testing (GB/T 2975- 1998, eqv ISO 377: 1997)

GB/T 3077 Alloy Structure Steels

GB/T 4336 Standard Test Method For Spark Discharge Atomic Emission Spectrometric

Analysis of Carbon and Low-alloy Steel (Routine Method)

GB/T 5777 Seamless Steel Pipe and Tubing-methods for Ultrasonic Testing (GB/T

5777-2008, ISO 9303: 1989, MOD)

GB/T 7735 Steel Tubes—the Inspection Method on Eddy Current Test (GB/T 7735-2004,

ISO 9304: 1989, MOD)

GB/T 12606 Steel Tubes-The Testing Method of Magnetic Flux Leakage (GB/T 12606-

3

1999, eqv ISO 9402: 1989, ISO 9598: 1989)

GB/T 17395 Dimensions, Shapes, Masses and Tolerances of Seamless Steel Tubes

(GB/T 17395-2008, ISO 1127: 1992, ISO 4200: 1991, ISO 5252: 1991, NEQ)

GB/T 20066 Steel and Iron-Sampling and Preparation of Samples for the Determination

of Chemical Composition (GB/T 20066--2006, ISO 14284: 1996, IDT)

GB/T 20123 Steel and Iron—Determination of Total Carbon and Sulfur Content Infrared

Absorption Method after Combustion in an Induction Furnace (Routine Method) (GB/T

20123-2006, ISO 15350: 2000, IDT)

GB/T 20124 Steel and Iron—Determination of Nitrogen Content—Thermal

Conductimetric Method after Fusion in a Current of Inert Gas (Routine Method) (GB/T

20124-2006, ISO 15351: 1999, IDT)

GB/T 20125 Low-Alloy Steel-Determination of Multi-element Contents-Inductively

Coupled Plasma Atomic Emission Spectrometric Method

3. Order content

Contract or order ordering steel pipes according to this Standard shall include the

following contents:

a) Standard number;

b) Product name;

c) Grade of steel, quality classification must be indicated while necessary;

d) Dimensions;

e) Order quantity (total weight or total length);

f) Delivery state;

g) Special requirement

4. Dimension, shape and weight

4.1 Outside diameter and wall thickness

The outside diameter (D) and wall thickness (S) of steel tubes shall comply with the

provisions of GB/T 17395-1998.

According to the requirements of the purchaser and through the mutual negotiation of

both the purchaser and the supplier, the steel tube with other outside diameters and wall

thicknesses can be supplied.

4.2 Allowable deviation of outside diameter and wall thickness

4.2.1 The allowable deviation of outside diameter of the steel tube shall be in accordance with

those specified in Table 1.

4

Table 1 Allowable Deviation of Outside Diameter of the Steel Tube in: mm

Steel tube kinds Allowable deviation

Hot rolling (extruding and expanding) steel tube ±1%D or ±0.50, take the larger value

Cold drawing (rolling) steel tube ±1%D or ±0.30, take the larger value

4.2.2 The allowable deviation of wall thickness of the hot rolling (extruding and expanding)

steel tube shall be in accordance with those specified in Table 2. Table 2 Allowable Deviation of Wall Thickness Hot Rolling (Extruding and Expanding) Steel Tube

in: mm

Steel tube kinds Nominal outside

diameter of steel tube S/D Allowable deviation

Hot rolling (extruding) steel tube ≤102 — ±12.5%S or ±0.40, takes the larger value

>102 ≤0.05 ±15% S or±0.40, takes the larger value

>102 >0.05~0.10 ±12.5% S or±0.40, takes the larger value Hot rolling (extruding) steel tube

>102 >0.10 SS

%5.12%10

Hot expanding steel tube — ±15%S

4.2.3 The allowable deviation of wall thickness of the cold drawing (rolling) steel tube shall

be in accordance with those specified in Table 3.0.2. Table 3 Allowable Deviation of Wall Thickness of the Cold Drawing (rolling) Steel Tube in: mm

Steel tube kinds Nominal wall thickness of steel tube Allowable deviation

Cold drawing (rolling) ≤3 SS

%15%10

or ±0.15, take the larger value

Cold drawing (rolling) >3 SS

%5.12%10

+12.5%S

4.2.4 According to the requirements of the purchaser, through the mutual negotiation of both

the purchaser and the supplier and indicated in the contract, steel tube with allowable

deviation of dimensions excluded of Table 1, Table 2 or Table 3.

4.3 Length

4.3.1 Usual length

Usual length of the steel tube is 3000mm~12500mm.

4.3.2 Scope length

According to requirements of the purchaser, through the mutual negotiation of both the

purchaser and the supplier, and indicated in the contract, steel tube may be delivered

according to the scope length. The length scope shall be within the scope of usual length.

4.3.3 Cut-to-length and multiple lengths

4.3.3.1 According to requirements of the purchaser, through the mutual negotiation of both

the purchaser and the supplier, and indicated in the contract, the steel tube may be delivered

according to the cut length or multiple lengths.

4.3.3.2 The cut length of steel tube shall be within the usual length scope, and the allowable

deviation of the cut lengths shall comply with the following provisions:

a) The cut length is no greater than 6000 mm, mm; 100

5

b) The cut length is greater than 6000 mm, mm. 150

4.3.3.3 Total multiple length of the steel tube shall be within the usual length, the full-length

allowable deviation is mm, and multiple lengths shall be set aside kerf surplus according

to the following provisions:

200

a) The outside diameter is no greater than 159 mm, 5 mm~10 mm;

b) The outside diameter is greater than 159 mm, 10 mm~15 mm.

4.4 Tortuosity factor

4.4.1 The tortuosity factor of steel tube per meter shall be in accordance with those specified

in Table 4. Table 4 Tortuosity Factor of Steel Tube

Nominal wall thickness of steel tube /mm Tortuosity factor of per meter (mm/m)

≤15 ≤1.5

>15~30 ≤2.0

>30 or D≥351 ≤3.0

4.4.2 Full-length tortuosity factor of the steel tube shall be no greater than 1.5‰ of the total

steel tube length.

4.5 Noncircularity and wall unevenness

According to the requirements of the purchaser, through the negotiation of both the

purchaser and the supplier, and indicated in the contract, the noncircularity and wall

unevenness of steel tube shall be no more than 80% of the outside diameter and wall

thickness tolerances respectively.

4.6 Terminal shape

4.6.1 The steel tube with nominal outside diameter of no greater than 60 mm, the pipe

terminal shear drag shall be no more than 1.5 mm; the steel tube with nominal outside

diameter of greater than 60 mm, the pipe terminal shear drag shall be no more than 2.5% of

the nominal outside diameter of steel tube, but the maximum outside diameter shall be no

more than 6mm. The shear drag of the steel tube sees Figure 1.

6

Figure 1 Shear Drag

4.6.2 Terminal kerf burr of the steel tube shall be removed.

4.7 Weight

4.7.1 The steel tube shall be delivered according to the actual weight, or it may be delivered

according to theoretical weight. Calculation for theoretical weight of the steel tube complies

with GB/T 17395 and the steel density is 7.85 kg/dm3.

4.7.2 According to the requirements of the purchaser, through mutual negotiation of the

purchaser and the supplier, and indicated in the contract, the deviation between theoretical

weight and actual weight of the delivered steel tube shall comply with the following

requirements:

a) Unipivot steel tube: ±10%;

b) Steel tube with minimum lot's weight of 10t:±7.5%.

5. Technical requirements

5.1 Grade of steel and chemical composition

5.1.1 The grade and chemical composition (heat analysis) of carbon constructional quality

steel shall comply with the requirements of 10, 15, 20, 25, 35, 45, 20Mn and 25Mn specified

in GB/T 699.

The grade and chemical composition (heat analysis) of the low-alloy high-tensile

structural steel shall comply with GB/T 1591, therein, phosphine and sulfur content of steel

with quality grade of A, B and C shall not be greater than 0.030%.

The grade and chemical composition (heat analysis) of alloy structure steels shall comply

with GB/T 3077.

Chemical composition (heat analysis) of the steel in grades of Q235 and Q275 shall be in

accordance with those specified in Table 5.

7

Table 5 Chemical Composition (Heat Analysis) of Q235 and Q275 Steel

Chemical composition (mass fraction)a/%

P S Grade Quality grade C Si Mn

No greater than Alt(Total aluminium)b

A ≤0.22 —

B ≤0.20 0.030 0.030

—

C 0.030 0.030 — Q235

D

≤0.17

≤0.35 ≤1.4

0.025 0.025 ≥O.020

A ≤0.24 —

B ≤0.21 0.030 0.030

—

C 0.030 0.030 — Q275

D ≤0.20

≤0.35 ≤1.50

0.025 0.025 ≥O.020

a The content of residual elements Cr and Ni shall be no greater than 0.30%, and Cu content shall be no greater than

0.20%.

b When analyzing Als (acid-soluble aluminium), Als≥0.015%.

5.1.2 According to the requirements of the purchaser and through the mutual negotiation of

both the purchaser and the supplier, the steel tube with other grades can be produced.

5.1.3 When the purchaser requires product analysis, it shall be indicated in the contract, and

the allowable deviation of the chemical composition of the finished steel tube shall comply

with GB/T 222.

5.2 Manufacturing method

5.2.1 Smelting process of steel

The steel shall be smelted with electric arc furnace plus out-of-furnace refining or

oxygen converter plus out-of-furnace refining method.

Through the mutual negotiation of the purchaser and the supplier, the steel may also be

smelted by other method with higher requirements. If the purchaser specifies some smelting

process, the smelting process shall be clearly indicated in the contract.

5.2.2 Manufacturing method of the tubular billet

The tubular billet is made by continuous casting or hot rolling (forging), and the steel

ingot may also be used as tubular billet directly.

5.2.3 Manufacturing method of the steel tube

The steel tube shall be made with hot rolling (extruding and expanding) or cold drawing

(rolling) seamless method. If the purchaser specifies some steel tube manufacturing process,

the manufacturing process shall be clearly indicated in the contract.

5.3 Delivery state

5.3.1 The hot rolling (extruding and expanding) steel tube shall be delivered in hot rolling

state or heat treatment condition. If the purchaser requires delivery in heat treatment condition,

8

it shall be clearly indicated in the contract.

5.3.2 The cold drawing (rolling) steel tube shall be delivered in heat treatment condition.

According to the requirement of the purchaser, through the mutual negotiation of the

purchaser and the supplier, and indicated in the contract, the cold drawing (rolling) steel tube

may be delivered in cold drawing (rolling) state as well.

5.4 Mechanical properties

5.4.1 Tensile property

5.4.1.1 The tensile property of carbon constructional quality steel, low-alloy high-tensile

structural steel or Q235 and Q275 steel tubes shall be in accordance with those specified in

Table 6 in their delivery state.

5.4.1.2 Sample roughcast of alloy structure steel tube is heat-treated according to heat

treatment system recommended in Table 7, and the longitudinal tensile property measured for

the sample shall be in accordance with those specified in Table 7.

5.4.1.3 The mechanical properties of steel tube delivered in cold drawing (rolling) state

agreed by both the purchaser and the supplier.

9

Table 6 Mechanical Properties of Carbon Constructional Quality Steel, Low-alloy High-tensile

Structural Steel, or Steel Tubes in Grades of Q235 And Q275

Lower yield strength

ReLa/MPaImpact test

Wall thickness/mm

≤16 >16 30 >30

Post-breaking

extensibility

A/% Absorbed energy

KV2/J

Grade Quality

grade

Tensile strength

Rm/MPa

No less than

Temperature /℃

No greater than

10 — ≥335 205 195 185 24 — —

15 — ≥375 225 215 205 22 — —

20 — ≥410 245 235 225 20 — —

25 — ≥450 275 265 255 18 — —

35 — ≥510 305 295 285 17 — —

45 — ≥590 335 325 315 14 — —

20Mn — ≥450 275 265 255 20 — —

25Mn — ≥490 295 285 275 18 — —

A — —

B +20

C 0 Q235

D

375~500 235 225 215 25

-20

27

A — —

B +20

C 0 Q275

D

415~540 275 265 255 22

-20

27

A — — Q295

B 390~570 295 275 255 22

+20 34

A — —

B 20

+20

C 0

D — 20

34 Q345

E

470~630 345 325 295

21

-40 27

A — —

B 18

+20

C 0

D -20

34 Q390

E

490~650 390 370 350

19

— 40 27

A — —

B 18

+20

C 0

D -20

34 Q420

E

520~680 420 400 380

19

-40 27

C 0

D -20 34

Q460

E

550~720 460 440 420 17

— 40 27

a During the tensile test period, if yield strength cannot be measured, the specified non-proportion extension intensity

RP0.2 may be measured to replace ReL.

10

Table 7 Mechanical Properties of Alloy Steel Tube

Recommended heat treatment system a Tensile property

Quenching (normalizing) Tempering

Temperature /℃

Tensile

strength

Rm/MPa

Lower yield

strength f

ReL/MPa

Post-breaking

extensibility

A/%

Brinell Hardness

of steel tube

annealing or

high tempering

in delivery state

Serial

number Grade

For the

first time

For the

second time

Coolant Temperature

/℃ Coolant

No less than No greater than

1 40Mn2 840 — Water and oil 540 Water and oil 885 735 12 217

2 45Mn2 840 Water and oil 550 Water and oil 885 735 10 217

3 27SiMn 920 Water 450 Water and oil 980 835 12 217

4 40MnBb 850 oil 500 Water and oil 980 785 10 207

5 45MnBb 840 oil 500 Water and oil 1030 835 9 217

6 20Mn2Bb, c 880 oil 200 Water and air 980 785 10 187

835 540 10 179 7 20Crc, e 880 800 Water and oil 200 Water and air

785 490 10 179

8 30Cr 860 — oil 500 Water and oil 885 685 11 187





13 38CrSi 900 — oil 600 Water and oil 980 835 12 255

14 12CrMo 900 — air 650 air 410 265 24 179

15 15CrMo 900 — air 650 air 440 295 22 179

885 685 11 197 16 20CrMoc, e 880 — Water and oil 500 Water and oil

845 635 12 197

17 35CrMo 850 — oil 550 Water and oil 980 835 12 229

18 42CrMo 850 — oil 560 Water and oil 1080 930 12 217

19 12CrMoV 970 — air 750 air 440 225 22 241

20 12CrlMoV 970 — air 750 air 490 245 22 179

980 835 12 229 21 38CrMoAIe 940 — Water and oil 640 Water and oil

930 785 14 229

22 50CrVA 860 — oil 500 Water and oil 1275 1130 10 255

23 20CrMn 850 — oil 200 Water and air 930 735 10 187

24 20CrMnSie 880 — oil 480 Water and oil 785 635 12 207

1080 885 8 229 25 30CrMnSic, e 880 — oil 520 Water and oil

980 835 10 229

26 35CrMnSiAe 880 — oil 230 Water and air 1620 — 9 229

11

Table 7 (Continued)

Recommended heat treatment system a Tensile property

Quenching (normalizing) Tempering

Temperature /℃

Tensile

strength

Rm/MPa

Lower

yield

strength f

ReL/MPa

Post-breaking

extensibility

A/%

Brinell

Hardness of

steel tube

annealing or

high tempering

in delivery state

Serial

number Grade

For the

first time

For the

second

time

Coolant Temperature

/℃ Coolant

No less than No greater than

27 20CrMnTid-e 880 870 oil 200 Water and air 1080 835 10 217

28 30CrMnTid-e 880 850 oil 200 Water and air 1470 — 9 229

29 12CrNi2 860 780 Water and oil 200 Water and air 785 590 12 207

30 12CrNi3 860 780 oil 200 Water and air 930 685 11 217

31 12Cr2Ni4 860 780 oil 200 Water and air 1080 835 10 269

32 40CrNiMoA 850 — oil 600 Water and oil 980 835 12 269

33 45CrNiMoVA 860 — oil 460 oil 1470 1325 7 269

a The permissible adjustment range of heat treatment temperature listed in the table: ±20 for quenching;℃ ±30 for low℃ -temperature tempering;

±50 for high℃ -temperature tempering.

b The boracic steel may be normalizing before quenching, and the normalizing temperature shall be no higher than its quenching temperature.

c Delivered according to a group of data specified by the purchaser; when the purchaser is not specified, it may be delivered according to any

group of data therein.

d The first quenching of Cr-Mn-Ti steel may be replaced by normalizing.

e Isothermal quenching at temperature of 280 ~ 320 .℃ ℃

f During the tensile test period, if yield strength cannot be measured, the specified non-proportion extension intensity RP0.2 may be measured to

replace ReL.

5.4.2 Hardness test

The alloy structure steel tube delivered in annealing or high-temperature tempering state

and in wall thickness of no greater than 5mm, the Brinell hardness shall be in accordance with

those specified in Table 7.

5.4.3 Impact test

5.4.3.1 For low-alloy high-tensile structural steel and Q235 or Q275 steel tubes, when their

outside diameter is no less than 70mm and their wall thickness is no less than 6.5 mm, impact

test shall be made, while the impact absorbed energy and test temperature of its compound

ratio V-notch impact test shall be in accordance with those specified in Table 6. Impact

absorbed energy is calculated according to arithmetic mean value of three samples of one

group, single value of one of the samples therein is permitted to be less than the specified

value, but it shall be no less than 70% of the specified value.

5.4.3.2 Impact absorbed energy listed in Table 6 is the desired value of impact absorbed

energy for Charpy V-notch samples in standard dimension. When the steel tube dimension

cannot prepare samples in standard dimension, undersized bearing samples may be prepared;

when the undersized bearing impact sample is used, the desired value of minimum Charpy

V-notch impact absorbed energy shall be the product of desired value for the impact absorbed

12

energy of standard sized sample multiplied by reduction coefficient listed in Table 8. The

dimension of the impact sample shall give preference to select larger dimension. Table 8 Reduction Coefficient of Impact Absorbed Energy for Undersized Bearing Sample

Sample specifications Sample size (height×width) (mm×mm) Reduction coefficient

Standard sample 10×10 1.00

Small sample 10×7.5 0.75

Small sample 10×5 0.50

5.4.3.3 According to the requirements of the purchaser, through mutual negotiation of both

the purchaser and the supplier, and indicated in the contract, steel with other grades and

quality grades may also be made with Charpy V test, and its test temperature, testing size and

impact absorbed energy are determined by the agreement of both the purchaser and the

supplier.

5.5 Technical properties

5.5.1 Flattening test

The steel tube made of steels in grades of 10, 15, 20, 25, 20Mn, 25Mn, Q235, Q275,

Q295, Q345, with outside diameter of >22 mm~400mm and with wall thickness to outside

diameter ratio of no greater than 10% shall be made with flattening test; after flattening, the

flat plate interval of the steel tube shall be in accordance with those specified in Table 9.

After flattening, crack or rupture is not allowed to emerge on the sample. Table 9 Flat Plate Interval after Steel Tube Flattening

Grade Flat plate interval of the flattening test (H)a/mm

10, 15, 20, 25, Q235 2/3D

Q275, Q295, Q345, 20Mn, 25Mn 7/8D

a The minimum value of flat plate interval (H) for the flattening test shall be 5×wall thickness of the steel tube.

5.5.2 Bending test

According to the requirements of the purchaser, through the mutual negotiation of both

the purchaser and the supplier, and indicated in the contract, steel tube with the outside

diameter of no greater than 22mm may be made with bending test, with bend angle of 90°,

and bend core radius of 6×outside diameter of the steel tube; after the bending, the sample

sinuosity is not allowed to emerge crack or rupture.

5.6 Surface quality

Inside and outside surface of the steel tube are not allowed with visible crack, foldover,

scar, rolling and delamination. These flaws shall be removed completely, and the removing

depth shall not be more than the minus tolerance of the nominal wall thickness; the practical

wall thickness at the removing part shall be no less than the minimum allow of the wall

thickness deviation.

As for other partial flaws, if their wall thickness is no less than the minus tolerance, they

are allowed to be present.

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5.7 Nondestructive test

According to the requirements of the purchaser, through mutual negotiation of both the

purchaser and the supplier, and indicated in the contract, the steel tube may be nondestructive

tested with one or more of the following methods, or with other methods.

a) The artificial flaw dimension for making ultrasonic inspection according to GB/T

5777: L3 (C10) for cold drawing (rolling) pipe; L4 (C12) for hot rolling (extruding and

expanding steel tube);

b) Eddy current inspection is made according to requirements of GB/T 7735, with its

acceptance grade is A;

c) Magnetic leakage test is made according to requirements of GB/T 12606, with its

acceptance grade is L4.

6. Test method

6.1 The dimensions and contour of steel pipe shall be measured with the measuring tools in line

with accuracy requirement.

6.2 The internal and external surfaces of steel pipe shall be subject to visual inspection under

sufficient lighting conditions.

6.3 The sampling method and test method for other inspection items of steel pipe shall meet the

requirements as set in Table 10.

Table 10 Inspection item, sampling quantity, sampling method and test method No. Inspection item sampling quantity sampling

method test method

1 Chemical composition One sample from each furnace GB/T 20066 GB/T 223 GB/T 4336 GB/T 20123 GB/T 20124 GB/T 20125

2 Tensile test One sample from each of two pipes for each batch

GB/T 2975 GB/T 228

3 Hardness test One sample from each of two pipes for each batch

GB/T 2975 GB/T 231.1

4 Impact test One group of 3 samples from each of two pipes for each batch

GB/T 2975 GB/T 229

5 Flattening test One sample from each of two pipes for each batch

GB/T 246 GB/T 246

6 Bending test One sample from each of two pipes for each batch

GB/T 244 GB/T 244

7 Ultrasonic flaw detection test Piece by piece --- GB/T 5777

8 Eddy current test Piece by piece --- GB/T7735

9 Magnetic flux leakage flaw detection test

Piece by piece --- GB/T 12606

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7. Inspection rules

7.1 Examination and acceptance

The examination and acceptance of steel pipe shall be carried out by the quality and technical

supervision department of the Supplier.

7.2 Rules for batch grouping

7.2.1 Examination and acceptance of steel pipe shall be conducted in terms of batch.

7.2.2 If the steel pipes are no longer heat treated after cut into single pieces, then, all the segments

cut from the steel pipe rolled from one pipe ingot shall be deemed as one piece.

7.2.3 Each batch shall be composed of the steel pipes of the same grade, the same furnace number,

the same size and the same treatment system (furnace). The quantity of each batch of steel

pipes shall not exceed the following provisions:

a) Outer diameter no greater than 76mm and wall thickness no greater than 3 mm: 400

pieces;

b) Outer diameter greater than 351mm: 50 pieces;

c) Other dimensions: 200 pieces.

7.2.4 When special requirements are proposed by the Buyer in advance, one batch can be

composed of the steel pipes of the same grade and the same size from different furnace

numbers as for 10, 15, 20, 25, 35, 45, Q235, Q275, 20Mn and 25MN.

7.2.5 For the number of pieces of remaining steel pipes, if it is no less than 50% of the above

provisions, it shall constitute one batch separately, if less than 50% of the above provisions, it

can be integrated into the adjacent batch of the same grade, furnace number and size.

7.3 Sampling quantity

The sampling quantity for each inspection item of each batch steel pipe shall meet the

requirement of Table 10 hereof.

7.4 Rules for reinspection and determination

The reinspection and determination of steel pipes shall meet the requirement of GB/T 2102.

8. Packaging, marking and quality certification

The packaging, marking and quality certification of steel pipes shall meet the requirement of

GB/T 2102.

16-GB-T 8162-1999-Seamless Steel Tubes for Structural Purposes

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Transcript of 16-GB-T 8162-1999-Seamless Steel Tubes for Structural Purposes