t c v n v i e t n a m e s e s t a n d a r d

tcvn 5317 : 2001

mobile offshore units -

rules for classification and construction

materials

Hµ néi - 2001

TCVN 5317:2001

Foreword

TCVN 5317:2001 replaces to TCVN 5317:1991.

TCVN 5317:2001 is edited by Vietnam Register and TCVN/TC8 ''Shipbuilding and Offshore'' Technical

Standard Board, is proposed by Ministry of Transportation and Standard - Measure - Quality General

Department, is promulgated by Ministry of Science, Technology and Environmental

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TCVN 5317:2001

table of content

1. General............................................................................................................................................... 7

1.1. Application...............................................................................................................................................7

1.2. Referance standards...............................................................................................................................7

1.3. Definitions and explanations .................................................................................................................8

1.4. Process of manufacture .........................................................................................................................8

1.5. Chemical composition............................................................................................................................8

1.6. Testing and inspection ...........................................................................................................................8

1.7. Execution of testing and inspection .....................................................................................................9

1.8. Identification of materials.......................................................................................................................9

1.9. Test certificates .......................................................................................................................................9

1.10. Quality and repair of defects ...........................................................................................................10

1.11. Additional test befor rejection.........................................................................................................11

1.12. Marking ..............................................................................................................................................11

2. Rolled steels .................................................................................................................................... 12

2.1. General ...................................................................................................................................................12

2.2. Steel for hull...........................................................................................................................................13

3. Castings........................................................................................................................................... 16

3.1. General ...................................................................................................................................................16

4. Steel forging .................................................................................................................................... 16

4.1. General ...................................................................................................................................................16

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TCVN 5317:2001

5. Z - steel .............................................................................................................................................16

5.1. General provision ................................................................................................................................. 16

5.2. Chemical composition ......................................................................................................................... 17

5.3. Mechanical properties.......................................................................................................................... 17

5.4. Heat treatment ...................................................................................................................................... 18

5.5. Sampling and scope of testing ........................................................................................................... 18

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TCVN 5317:2001

Introduction

Mobile Offshore Units - Rules for classification and construction include :

TCVN 5309 : 2001 Classification

TCVN 5310 : 2001 Hull

TCVN 5311 : 2001 Equipment Arrangement

TCVN 5312 : 2001 Stability

TCVN 5313 : 2001 Subdivision

TCVN 5314 : 2001 Fire protection, detection and extincition

TCVN 5315 : 2001 Machinery Installations

TCVN 5316 : 2001 Electrical Installations

TCVN 5317 : 2001 Materials

TCVN 5318 : 2001 Welding

TCVN 5319 : 2001 Safety Equipment

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TCVN 5317:2001

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TCVN 5317:2001

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Vietnamese TCVN 5317:2001

Mobile Offshore Units - Rules for classification and construction

Materials

. General

.1. Application

This standard is applicable to materials, used to manufacture structures, equipment, as well as

relevant parts of mobile offshore units (abbreviation is unit) defined in TCVN 5309:2001.

Materials and equipment of the unit are to comply with corresponding requirements in TCVN 6259-

7:1997: Welding and requirements in this standard.

Materials having characteristics other than those specified in this Part may be used when the detailed

design data, manufacturing procedure and their use are specially approved by VR. In this case,

detailed data relating to the process of manufacture, chemical composition, mechanical properties,

etc. of the materials are to be submitted to VR for approval .

.2. Reference standards

TCVN 6259-1:1997 to TCVN 6259-11:1997 Rules for classification and construction of steel sea-going

ship .

Mobile Offshore Units - Rules for classification and construction include:

TCVN 5309 : 2001 Classification

TCVN 5310 : 2001 Hull

TCVN 5311 : 2001 Equipment Arrangement

TCVN 5312 : 2001 Stability

TCVN 5313 : 2001 Subdivision

TCVN 5314 : 2001 Fire protection, detection and extincition

TCVN 5315 : 2001 Machinery Installations

TCVN 5316 : 2001 Electrical Installations

TCVN 5317:2001

TCVN 5317 : 2001 Materials

TCVN 5318 : 2001 Welding

TCVN 5319 : 2001 Safety Equipment

1.3. Definitions and explanations

1 The definitions and explanations concerning the general terminology of the rules are given in 1.3

TCVN 5309:2001, and TCVN 6259-1997 .

2 The following definitions and explanations are applied in this standard :

(1) Lamellar tearing means breaking of welded structure elements made of rolled plates or

pipes due to considerable welding stresses and/or external loads applied in the direction

perpendicular to the plate surface, or due to both.

(2) Z-steel means steel with guaranteed through thickness properties which is intended for

welded structures and can withstand considerable stresses perpendicular to the plate

surface .

1.4. Process of manufacture

1 The materials specified in this Part, unless otherwise specially provided or deemed appropriate by VR,

are to be manufactured at the works approved by VR with regard to the process of manufacture of the

materials .

2 The steel material specified in this Part is to be manufactured by basic oxygen convertor, electric

furnace or other processes specially approved by VR .

3 Primary materials such as ingot, slab or billet supplied to other manufacturers or other works in the

same manufacturer are to be manufactured by the process of manufacture of these materials

approved by VR .

1.5. Chemical composition

1 The chemical composition is to be analyzed at an adequately equipped and competently staffed

laboratory on samples generally taken from each melt, and is to comply with the requirements for

chemical composition specified in this rules .

2 A check analysis may be required by VR where deemed necessary .

1.6. Testing and inspection

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TCVN 5317:2001

1 Materials are to be tested and inspected in the presence of the VR's Surveyor except where

otherwise specially provided, and are to comply with the requirements in this Part .

2 Materials having characteristics other than those prescribed in this part are to be tested and inspected

according to the approved specifications for the testing .

3 VR may dispense with the tests for materials having the appropriate certificates.

4 VR may modify the requirement of presence of testing and inspection by the Surveyor where the

quality of materials and the quality control system of manufacturer are deemed appropriate by VR .

5 VR may request tests under condition of higher or lower temperatures than those specified in this Part

in consideration of the intended service condition of the materials .

1.7. Execution of testing and inspection

1 The manufactures are to afford the surveyor all necessary facilities and access to all relevant parts of

the works to enable him to verify that the approved process is adhered to.

2 The manufactures is to show the order specifications, special requirements, etc. of the materials to the

surveyor prior to the material test.

3 All tests and inspections are to be carried out the place of manufacture prior to delivery, but in the

event of any material proving unsatisfactory in the process of being worked, it is be rejected,

notwithstanding any previous certificate of satisfactory testing and inspection where the surveyor

considers necessary.

4 The testing machines used for the mechanical testing are to be those which have the effective

certificates issued by VR or other organization recognized by VR or other standards deemed

appropriated by VR .

1.8. Identification of materials

1 The manufacturers is to take a suitable measure for identification of ingots, slabs, castings, forgings

and finished pieces, etc. which will enable the material to be traced to the processing details as

mealting, rolling, forging, heat treatments, etc., at all phases of manufacturing process .

1.9. Test certificates

1 The manufacturer is to submit test certificate on the rolled steel materials, which have passed the

specified test requirements for each material mark for the Surveyor's signature. However, another

method may be used instead of Surveyor's signature, provided that it is deemed appropriate by VR .

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TCVN 5317:2001

2 The test certificate specified in -1 are to contain, in addition to the dimensions, mass, etc., of the steel

material, at least items (1) through (9) of the following particulars :

(1) Purchaser's order number and if known the ship name which the material is intended ;

(2) Identification number or symbol ;

(3) Identification of manufacturer ;

(4) Identification of grade of material ;

(5) Chemical composition (ladle analysis on elements specified in the requirement and added

when necessary) .

(6) Carbon equivalent (Ceq) or cold cracking susceptibility (Pcm) calculated from the following

formula using ladle analysis (only in such a case as specified in this Part) :

(%) 15

CuNi5

VMoCr6

MnCC eq+

+++

++=

5B10V

15Mo

20Cr

60Ni

20Cu

20Mn

30SiCPcm ++++++++= (%)

(7) Mechanical test results;

(8) Condition of heat treatment (e.g. normalized or controlled roll except for as rolled) ;

(9) Deoxidization practice is to be stated (rimed steel only).

The manufacturer is to enter the following statement on the certificate to show that the steel material has

been made by an approved process, and the declaration is to be signed by the personnel of the

manufacturing shop in charge of product quality control or inspection. However, another method may be

used instead of the signature of the person in charge, provided that it is deemed appropriate by VR .

3 The requirements in -1 to -3 are to be applied to the materials which are specified in this Part but

which are other than rolled steel materials.

4 Where primary materials such as ingot, slab or billet are not produced in the works at which it is rolled

or forged, a certificate is to be supplied to the surveyor at the rolling, piping or forging works stating the

process by which it is was manufactured, the name of manufacturer who supplied these, the number

of the cast from which it was made and the ladle analysis. The this case, the manufacturing process of

primary materials such as ingot, slab or billet are deemed appropriate by the surveyor .

1.10. Quality and repair of defects

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TCVN 5317:2001

1 All materials are to be free from harmful defects. Welding or other means for the purpose of repairing

defects is not permitted unless the extent and method of repair (including welding procedure and heat

treatment) are approved by VR. The repair of defects is to be carried out in the presence of the

surveyor, unless otherwise agreed .

1.11. Additional test befor rejection

1 Where part of the results of any mechanical test except impact test does not conform to the

requirements, but the remainders are satisfactory, additional test specimens twice in number may be

taken from the same material and retests for the failed test may be carried out. In such a case, all of

the test specimens are to conform to the requirements of the Rules.

2 Where the results of impact test do not conform to the requirements, additional tests are to be carried

out in accordance with the requirements in each Chapter .

3 If a heat treated material fails to meet the requirements in any test, retests may be allowed after being

heat treated again. In this case, however, the material is not to be considered as having complied with

the requirements unless all tests fully comply with the test requirements .

4 If the percentage of elongation of any tensile test specimen is less than that specified and any part of

fracture is outside the one-fourth of the gauge length from the center of gauge length, the test is to be

considered as invalid, and an additional test for the material from which the first test specimen has

been taken may be allowed .

1.12. Marking

1 Every materials complying with the requirements is to be clearly stamped with VR brand including the

marks deemed appropriate by VR and material grade mark, and marked with the following particulars

in at least one position by the maker .

(1) Name or mark to identify the maker ;

(2) Number or mark to identify the piece ;

(3) Name, order number or other identification marks (if required by the purchaser ).

2 Materials that are unsuitable for stamping may be marked with brands, seals or by other suitable

means .

3 Materials that cannot be stamped and marked in accordance with the requirements in -1 and -2 due to

small size may be properly marked in the lump .

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TCVN 5317:2001

2. Rolled steels

2.1. General

1 Rolled steels used in manufactured unit is to comply with requirements in Chapter 3, Part 7A, TCVN

6259-7:1997 and following additional requirements.

2 Types of rolled steel used in manufacture of unit is given table 2.1-1.

3 Steel for special structure is to be approved by TH VR for use according to the purpose and is to be

manufactured under the supervision of the VR by works recognized by that body.

4 Steel for special and primary structures is to be killed and finegrain treated.

5 Steel plates intended for special structures are to undergo the ultrasonic examination. The

examination should be carried out in accordance with standards approved by the VR .

Table 2.1-1 Category of rolled steels for hull

Kind of steels Symbols specified in part 7A

- TCVN 6259-7:1997

Symbols specified in this part

KA KA

KB KB

KD KD

Mild steels

KE KE

KA32, KA36, KA40 KAH

KD32, KD36, KD40 KDH

KE32, KE36, KE40 KEH

High tensile steels

KF32, KF36, KF40 KFH

KA43, KA47, KA51 AQ1

KA56, KA63, KA70 AQ2

KD43, KD47, KD51 DQ1

KD56, KD63, KD70 DQ2

KE43, KE47, KE51 EQ1

KE56, KE63, KE70 EQ2

KF43, KF47, KF51 FQ1

High strength quenched

and tempered rolled

steel

KF56, KF63, KF70 FQ2

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TCVN 5317:2001

Material coefficients (K) due to kind of those corresponding to tensile strengthare given in Table :

Table 2.1-2 Material coefficient

Kind of steels Symbols of materials Coefficient (K)

Mild steel KA , KB , KD , KE 1,0

KA32, KD32, KE32, KF32 0,78

KA36, KD36, KE36, KF36 0,72

High tensile steels

KA40, KD40, KE40, KF40 *

KA43, KD43, KE43, KF43 *

KA47, KD47, KE47, KF47 *

KA51, KD51, KE51, KF51 *

KA56, KD56, KE56, KF56 *

KA63, KD63, KE63, KF63 *

High strength quenched

and tempered rolled steel

KA70, KD70, KE70, KF70 *

Note: * At the descretion of VR

2.2. Steel for hull

Application of steels for structural members for hull are given in following Fig. where the design service

temperature of materials is lower than -50oC and plate thickness is exceeding to 70mm, however, applied

steels are satisfactory of the VR..

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TCVN 5317:2001

Fig. 3.2-1 : Application of Mild Steel

*

At the

discrection of

the VR

KEKDKB KA 10

50

40

30

20

0

Thickn. (mm)

(Special)-50 -30 -400 -10 -20

-50-40 (Primary)-30-20 0 -10 o Service temp. ( C) (Secondary)-50-40-30 -20-10 0

Fig 3.2-2 : Application of High Tensile Steel

Thick. (mm) 50

KAH KDH KEH

At the

discrection of

the VR

KFH

40

30

20

10

0

Service Temp. ( C) o 0 -10 -20 -30 (Secondary-40 -50

0 -10 -20 -30 -40 -50 (Primary) 0 -50 -10 20 -30 -40 (Special)

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TCVN 5317:2001

Fig. 3.2-3 : Application of High Strength Quenched and Tempered Rolled Steel(AQ1,DQ1,EQ1 vµ FQ1)

Thickness (mm)

AQ1

*

DQ1 EQ1 FQ1

At the

discrection

of the VR

50

40

30

20

10

0 Service Temp. ( C) o 0 -10 -20 -30 -40 -50 (Secondary)

0 -10 -20 -50 (Primary)-30 -40 -50 (Special)0 -10 -20 -30 -40

Fig. 3.2-4 : Application of High Strength Quenched and Tempered Rolled Steel(AQ2,DQ2,EQ2 vµ FQ2)

AQ2

Thickness (mm)

*

EQ2DQ2 FQ2

At the

discrection of

the VR

50

40

30

20

10

0

o -10 -20 -30 -40 Service temp. ( C) -50 (Secondary)

0 -10 -20 -30 -40 -50 (Primay)

-10 (Special) 0 -20 -30 -40 -50

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TCVN 5317:2001

3. Castings

3.1. General

1 Steel castings used for unit has to comply with the requirements in this standard as well as

requirements of Chapter 5, Part 7 - Materials TCVN 6259-7:1997.

2 Steel castings used for making welded structures as well as machinery items and equipment working

at minus degree is to have adequate impact energy. Absorbed energy and temperature are specified

in specification and dependent on minimum specified yield strength for each type of steel, temperature

for each structure is to be approved by VR.

3 Reduction of area in tensile test for steel casting is not to be less than 50%.

4. Steel forging

4.1. General

1 Steel forgings are to conform to the requirements of this standard as well as requirements of Chapter

6, Part 7, Materials, TCVN 6259-7:1997.

2 Steel forging used for special purpose welded structure is to undergo impact testing at a temperature

which is equal to the design temperature for the structure in question, but is not higher than minus

20oC.

3 The guaranteed impact energy value obtained at impact testing is to be stated in the technical

documentation proceeding from the tensile strength of a steel grade and is to be agreed with the VR,

but in no case shall it be less than 30 J when V-notch specimens are tested.

5. Z - steel

5.1. General provision

1 The steel is to be manufactured by the open hearth, electric or basic oxygen process, and is to be

subsequently treated to obtain the required plastic properties of the rolled products in the through

thickness direction. The procedure of treating the steel should be indicated in the type approvall

Certificate and/or Recognition Certificate issued for the works .

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TCVN 5317:2001

5.2. Chemical composition

1 The basic element and impurities content in carbon and carbon-manganese steel is not to exceed the

values indicated in Table 5.1.

2 As Z-steel, hull structural steel conforming to the Rules may be used provided the requirements of this

Chapter are complied with VR

Table 5.1 Chemical composition of Z-steel (%) (max)

C Mn Si P S

0,18 1,16 0,50 0,03 0,01

3 Z-steel of alternative chemical compositions will be approved by the Register provided that adequate

weldability in conditions under which MODU structure are assembled and resistance to brittle fracture

are guaranteed .

4 If the carbon equivalent (Cdl) in per cent , is to be determined, the following formula should be used:

Mn Cr + Mo + V Ni + Cu Cdl = C + ⎯⎯⎯ + ⎯⎯⎯⎯⎯⎯ + ⎯⎯⎯⎯⎯ (%)

6 5 15

and the value is to be stated in the Certificate

5 Z-steel is to be full killed and treated with grainrefining elements the content of which is determined

when approving the steel .

5.3. Mechanical properties

1 The reduction (Zz) of area after the tensile testing of Z-steel speciments the longitudinal axis of which

is perpendicular to the rolled product surface is not to be less 30%.

Proceding from the minimal service temperature of the structure, the impact test temperature for Z-steel

is to be in accordance with Table 5.2

Table 5.2 Minimal service temperature of structure

Minimal service temperature of structure, (oC) Impact test temperature, (oC)

-10 -20

-20 -40

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TCVN 5317:2001

-40 -60

2 The required impact energy value for testing V-notch speciments is not to be determined proceeding

from the minimal yield stress for Z-steel according to Table ( Table 5.3).

Table 5.3 The required impact energy value for testing V-notch speciments

Yield stress, (MPa) 235 315 355 390

Impact energy (J) KVL 27 31 34 39

(min ) KVT 18 21 24 26

Where:

KVL : Impact energy for longitudinal specimens

KVT : Impact energy for trensverse specimens

3 The energy is determined on three specimens which are to be cut out transverse to or longtitudinally

along the direction of rolling. Where the impact energy is determined on longitudinal specimens the

required impact energy value for transverse specimens is to be guaranteed by the manufacturer .

4 When Z-steel is tested for the purpose of recognizing the manufacturer the Register may require the

weldability to be checked and the brittle transition temperature to be determined by the method

approved by the Register. The transition temperature is to the in accordance with the service

temperature of the structure .

5 The Register may require the Z-steel resistance to brittle fracture to be confirmed by fracture

mechanics method, dropped weight testing, etc.

5.4. Heat treatment

1 Z-steel is to undergo heat treatment. The heat treatment procedure is to be chosen by the

manufacturer and stated in the Type Approval Certificate and/ or Recognition Certificate, or due to

both .

5.5. Sampling and scope of testing

1 For the purpose of Z-steel testing, fromeach end of a piece sample should be taken of which

specimens for tensile testing, a set of specimens for impact testing and a set of specimens for the

tensile testing in the through-thickness direction are then to be machined .

2 The sequence of machining and the dimensions of specimens as well as the prosedure of tensile and

impact testing are to be in accordance with Chapter 2, Part 7-A TCVN 6259-7:1997 .

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TCVN 5317:2001

3 The procedure of machining the specimens and the procedure of tensile testing in the through-

thickness direction should be agreed with the Register

4 The percentage reduction of area (Z0) os to be determined as an average value of tensile testing on

three specimens and is not to be lower than the required value .

5 Of each sample the following specimens are to be machined and tested:

(1) One specimen for tensile testing;

(2) One set of three specimens for impact testing;

(3) One set of three specimens for tensile testing in the through-thickness direction

6 For pieces 50 mm or over in thickness, an additional set of three specimens is to be machined to

undergo impact testing, the specimens being cut out with their axes coinciding with the module of the

liece thickness .

7 The Z-steel pieces are to undergo ultrasonic examination procedure as well as kinds and dimensions

of permissible defects are to be agreed with the .

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

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