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NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF

CHINA                                                     GB/T 8165-1997




              STAINLESS STEEL CLAD PLATES AND STRIPS




Publication date: November 11, 1997            Effective date: May 1, 1998
Issued by: The State Administration of Technical Supervision of P.R.China


                                       1
GB/T 8165-1997

FORWARD

The Japanese standard JISG 3601-1990__Stainless clad steels is non-equivalently
adapted by this standard.
The major technical differences between this standard and JISG 3601 are stated
below:
___ Product thickness range: in this standard, ≥ 4 mm; in JISG 3601, ≥ 8 mm.
___ Types of the clad steel plates: three types specified in this standard, i.e., the rolled
clad steel plate, the explosive-rolled clad steel plate and the explosive clad steel plate;
types specified in JISG 3601 include all the above mentioned three types and some
additional types like the forged-rolled clad steel plate and build-up (deposited) welded
clad steel plate. Since the said additional types are not so widely used, they are not
contained here in this standard.
___ Types of the stainless steels used as cladding metals: four major categories of
stainless steels are specified in this standard, i.e., the ferrite type, the austenite type,
the ferrite + martensite and ferrite + austenite type. Dual phase stainless steels with σb
of 590MPa ~ 850 MPa like the 00Cr18Ni5Mo3Si2 steel are categorized as cladding
steels, which means there is one more category in this standard compared with JISG
3601.
___ Classification of the clad steel plates: In this standard the clad steel plates are
classified as Class I, Class II and Class III as per the proportion between the
un-jointed area and the total area and the size of each single un-jointed area and the
number of the un-jointed spots. Class I refers to the clad steel plate free of any
un-jointed area and used for structural parts satisfactory to stringent machining
(processing) criteria. Class II refers to the clad steel plate with just a small amount of
un-jointed area and used for certain kinds of structural parts. And Class III refers to
the clad steel plate which can be used for ordinary structural parts that only take the
cladding metal as an anti-corrosion layer. Whereas in JISG 3601, there are just Class I
and Class II specified, and no tensile test is required for Class II clad steel palate.
___ Special inspection method: certain special inspection method is specified in this
standard for the clad steel plate with low plasticity so as to make sure that the
plasticity value of the plate is up to the standard σb value as required.
___ Shear strength at the cladding line: it is specified in this standard that for
Premium Class and Class I plates the claddingt line shear strength τb is ≥210 MPa
and for Class IIτb ≥200MPa. Whereas in JISG 3601 for plates of all the classes
the value τb is ≥200MPa.
___ Thickness deviation: the thickness deviation for the cladding metal layer
specified in this standard is tighter than that specified in JISG 3601.

The most recent amendment of this standard involves the following issues:
___ Addition of the clad steel plate as produced with the explosive process.
___More strict value required for unevenness of the plate.


                                             2
___ Expansion of the steel types and category.
___ The thickness classification for bending property is re-specified, and additional
thicknesses for the test.
___ Amendment to and correction of the inspection items and testing methods.
    From its effective date this standard shall supersede Standard GB 8165-37 __
Stainless Steel Clad Plates.
Appendix A is an appendix of this standard.
This standard is proposed by the Ministry of Metallurgical Industry of P.R.China.
This standard is centralizedly controlled by the National Technical Committee of Steel
Standardization.
The responsible units for drafting of this standard are Tianyuan Iron & Steel (Group)
Co., Ltd., Yingkou Medium Steel Plate Plant and the Explosive Processing Plant of
Beijing Mining Administration.
This standard was drafted mainly by: Du Wei, Wang Lixin, Liao Youqing, Ma Jinbao,
Ma Jianjun, Li Wenda and Qing Xiaozhong.
This standard was firstly published in July, 1987.




                                          3
 NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA
                                         GB/T 8165-1997

STAINLESS STEEL CLAD PLATES AND STRIPS                                 Substitution of
                                                                       GB 8165-87



1 Scope
This standard specifies requirements for the stainless steel clad plates and stripes as
manufactured with the explosive process, the explosive-rolling process and the rolling
process, covering types, dimensions, technical criteria, acceptance inspection
procedure, testing methods, packaging, identification and quality certification, etc.
This standard is applicable for the clad steel plates and strips made with stainless steel
as cladding metal layer and carbon steel and low-alloy steel as base metal layer and
with thickness ≥4 mm. Such clad steel plates are used for manufacture of structural
components like various kinds of pressure vessels and tanks as used in such fields as
petroleum industry, chemical industry, light industry, and sea water desalination and
nuclear industry, etc.



2 Normative reference
The following normative documents contains provisions, which through reference in
this text, constitute provisions of this standard. When this standard was published,
the editions of all the following normative documents are valid. In the event that any
of these publications has been amended, parties to agreements based on this standard
are encouraged to investigate the possibility of applying the most recent edition of
such amended normative document.
   GB/T 229-94          Charpy V-notch test method for metals
   GB/T 247-1977 General requirements for acceptance inspection, packaging,
                       identification and quality certification of steel plates and strips
   GB/T 709-88          Dimensions, profiles, weights and permissible deviations of
                       hot-rolled plates and strips
   GB/T 713-1997        Steel plates for boiler services
   GB/T 2975-82         Requirements for sampling of steel products for mechanical and
                       process property tests
   GB/T 3274-88          Hot-rolled heavy plates and strips of carbon structural steel
                       and low alloy structural steel
   GB/T 3280-92         Cold-rolled stainless steel plates
   GB/T 3531-1996 Low alloy steel plates for low-temperature pressure vessels
   GB/T 4229-84         Calculation method for weight of stainless steel plate
   GB/T 4237-92         Hot-rolled stainless steel plates
   GB/T 4334.3-84        55% nitric acid corrosion test method for stainless steel
   GB/T 4334.5-90 Sulfuric acid – cupper sulfate corrosion test method for stainless

                                            4
                 steel
  GB/T 5396-1995 Property testing methods for clad steel plates
  GB/T 6654-1996 Steel plates for pressure vessels
  YB(T) 40-87    Carbon steel and low alloy steel plates for pressure vessels
  YB(T)41-87     Carbon steel and low alloy steel heavy plates for boiler
                 manufacture
  ZB Y 230-84 General technical requirements for A type pulse-reflection
                 soniscope

3 Definitions
For the purpose of this standard, the following definitions apply:
3.1 Stainless steel clad plate and strip: compound material which is made with
carbon steel or low alloy steel as base metal layer and by means of the explosive
process or any other process to get it continuously clad at one side or both sides with a
stainless steel layer with certain thickness.
3.2 Cladding metal layer: the stainless steel layer in the clad steel plate which
contacts the working medium and play a role of corrosion resistance.
3.3 Base metal layer: the carbon steel or low alloy steel layer in the clad steel plate
that mainly bear the structural strength.
3.4 The explosive process: a cladding process to get the cladding metal and the base
metal metallurgically weld-jointed through explosion.
3.5 The explosive-rolling process: a cladding process to first get the cladding metal
and the base metal metallurgically welded on through explosion, and then welded on
through rolling.
3.6 The rolling process: a cladding process to get the cladding metal and the base
metal welded on just through rolling and without explosion.
3.7 Cladding line: the border line between the cladding metal layer and the base
metal layer in the clad steel plate.
3.8 Joint rate: the proportion (%) of metallurgically welded on area between the
cladding metal layer and the base metal layer in the clad steel plate to the total
cladding line area.
3.9 Weld-repair: an operation process involving steps, namely, first removing the
cladding metal layer from the un-jointed area, then building up (depositing) stainless
steel on the base metal layer, and finally get the repaired plate undergo various proper
treatments so as to keep cladding metal layer of the clad steel plate having the
originally-required properties.
3.10 Internal bending and external bending tests: the internal bending test means a
cold-bending test with stainless cladding layer inside the bending curve; when the
stainless cladding layer is outside the bending curve, the test is called external
bending test.

4. Types and Classification
4.1 Manufacturing process
4.1.1 The stainless steel cladding layer of the clad steel plate and strip can be


                                            5
jointed with the base metal layer at one side or both sides thereof.
4.1.2 The clad steel plate and strip can be produced with the explosive process
(coded B) or the rolling process (coded R) or the explosive-rolling process (coded
BR).

4.2 Classification
According to their manufacturing processes the clad steel plates and strips are
classified and coded as the following Table 1.

Table 1 Classification and coding of clad steel plates
   Class                               Code                 Application
                 Explosive   Rolling    Explosive-
                 process     process    rolling process
Class I          BI          RI         RBI               For making of structural parts
                                                          free of any un-jointed area and
                                                          subjected to stringent processing
                                                          criteria.
Class II         BII         RII        RBII              For making of structural parts
                                                          allowable for a small amount of
                                                          un-jointed area.
Class III        BIII        RIII       RBIII             For     making     of  ordinary
                                                          structural parts taking the
                                                          cladding     metal just as an
                                                          anti-corrosion layer



5 Dimensions , profiles and weights
5.1 Dimensions
5.1.1 Thickness
        clad steel plate: no less than 8 mm;
        clad steel strip: 4 mm ~ 8 mm.
5.1.2 Width
        clad steel plate: 1450 mm ~ 3000 mm
        clad steel strip: 1000 mm ~ 1400 mm
5.1.3 Length
        clad steel plate and strip: 4000 mm ~ 10000 mm

5.1.4 Thickness of the cladding metal layer: 0.5 ~ 14mm, normally 2 mm ~ 3mm;
If requested by the customer, the thickness may also be determined based on
agreement between the supplier and the customer.
5.1.5 Minimum thickness of the base metal layer
        6mm, when the clad steel plate total thickness is more than 8 mm;
        For the clad steel strip, the minimum thickness shall be determined based on
agreement between the supplier and the customer.

                                          6
5.2 Permissible dimensional deviations
5.2.1 The permissible thickness deviations of the clad steel plate and strip shall be
in compliance with the values as indicated in the following Table 2.


Table 2 Permissible thickness deviations
Permissible thickness deviations for Permissible total thickness deviations for clad steel
cladding layer                       plate and strip
 Class I, Class II                 Class III       Plate total thickness mm              Permissible deviations %
                                                   Strip              Plate              Classes I ,II     Class III
No more than ±9%              No more than         4~8                  −                +10, −8           ±9
of cladding layer             ±10%        of         −                ≥8 ~ 15            +9, −7            ±8
nominal thickness,            cladding layer         −                16 ~ 25            +8, −6            ±7
and no more than 1            nominal                −                26 ~ 30            +7, −5            ±6
mm.                           thickness, and         −                31 ~ 60            +6, −4            ±5
                              no more than 1                             >60             As      per       As     per
                              mm.                                                        agreement         agreement


5.2.2 The permissible width deviations of the clad steel plate and strip shall be in
compliance with the values as indicated in the following Table 3, while the
permissible length deviations shall be in accordance with applicable specification for
the steel plate used as base metal layer. Any special deviation shall be subjected to
agreement between the supplier and the customer.

 Table 3            Permissible width deviations
        Permissible W. deviation      < 1450                                      ≥1450
Nominal thickness                                        Class I              Class II              Class III
      4~8                                                      +6                 +10                      −15
                                                               0                    0                        0
      > 8 ~ 25                     As per GB 709               +20                  +25                      +25
                                                               0                    0                         0
      ≥25                                                      +25                  + 30                     +35
                                                               0                    0                         0


5.3 Unevenness
The unevenness of the clad steel plate and strip shall be in compliance with the values
as listed in the following Table 4. No obvious unevenness shall be permitted.

Table 4 Unevenness of clad steel plate
             Width                     Permissible unevenness within the specified width range
Plate total thickness                 1000 ~ 1400                    > 1450 ~ 1800                       > 1800
            4~8                                8                              9                            10


                                                           7
          > 8 ~ 25                     10                        14                       15

          ≥ 26                         8                         12                       14


5.4 The clad steel plate and strip shall be delivered with theoretic weights. The
base metal layer density shall be 7.85g/cm2, while the cladding metal layer shall be as
per relevant requirement as specified in Standard GB 4229.

6 Technical requirements
6.1 The chemical compositions of both the cladding metal and the base metal shall
be in accordance with the requirements of the applicable standards as shown in the
following Table 5. In case of the explosive process, both the cladding steel plate and
the base steel plate shall conform to their applicable specifications respectively, and
be furnished together with the original (or duplicated) mill quality certificates. No
jointed stainless steel plates shall be allowed to be used as the cladding metal of the
clad steel plate without permission by the customer.

Table 5 Applicable standards (specifications) for the cladding metal and the
        base metal
              Cladding metal                                     Base metal
Standard No.         GB/T 3250                      Standard No.        GB 3274        GB 713
                     GB/T 4237                                          GB 3531        GB 6654
                                                                        YB(T) 40       YB(T) 41
Typical      steel   0Cr13                          Typical steel       Q235-A
grades               0Cr13Al                        grades              Q235-B
                     0Cr17                                              20
                     0Cr17Ti                                            20R
                     0Cr18Ni9                                           20g
                     0Cr18Ni10Ti                                        16MnR
                     0Cr18Ni10                                          15CrMoR
                     0Cr17Ni12Mo2
                     0Cr17Ni14Mo2
                     0Cr18Ni5Mo3Si2


6.2 Clading line joint rate
6.2.1 The jointed area rate of the cladding metal and base metal of the clad steel
plate and strip shall be up to the requirement as indicated in the following Table 6.
Table 6 Area joint rate of the clad steel plate
Class of cladding line joint     Plate class code      Joint rate (%)     Un-joint condition
rate
     Class I                     BI                                       No     un-jointed    area   is
                                 BRI                       100            permitted.
                                 RI


                                                8
        Class II                        BII                                                   For any single un-jointed spot,
                                        BRII                               ≥99                the length shall be no more
                                        RII                                                   than 50 mm, and the area no
                                                                                              more than 20 mm2.
    Class III                           BII                                                   For any single un-jointed spot,
                                        BRII                               ≥95                the length shall be no more
                                        RII                                                   than 75 mm, and the area no
                                                                                              more than 45 mm2.
6.2.2     In the event that the joint rate of any clad steel plate failed to meet relevant
requirement listed in the above mentioned Table 6, it shall be allowed to get the
defective cladding metal layer repaired via fusion welding, and in this case the
following requirements have to be met.
6.2.2.1 After getting the defective cladding metal removed, a 0.2 ~ 0.5 mm thick
base metal layer shall have to be cut off.
6.2.2.2 The weld-repair shall be conducted by qualified operator and with approved
welding process. The weld-repair shall be recorded, and the record shall be submitted
to the customer.
6.2.2.3 The weld-repaired area shall be inspected with the ultrasonic method, and
if the area is qualified, then a coloring inspection shall be further made. The surface of
the weld-repaired area shall be free of any crack and porosity. For any clad steel plate
as specified in the order to be used for pressure vessel purpose, no more than 2 times
of weld-repairs shall be permitted. The surface of the weld-repaired area shall be
properly ground with the thickness remaining in the range of the minimum plate
thickness as required.

6.3 Mechanical properties
The mechanical properties of the clad steel plate and strip shall be in compliance with
the values as listed in the following Table 7.

Table 7              Mechanical properties of clad steel plate
        Properties     Shear strength   Yield strength            Tensile strength          Elongation           Impact
Class                  τ b, MPa ≥       σs , MPa                  σb , MPa                  δ, %                 energy, A?, J
Class I                                 No less than the          No less than the          No less than         As    per       the
                           210          standard      value       standard          lower   the   standard       standard value
Class II                                of      the   base        limit value, and no       value of the         specified for the
                                                1)                                                         .3)
Class III                  200          plate                     more       than     the   base plate .         base plate.4)
                                                                  standard          upper
                                                                  limit value of the
                                                                  base          plate__
                                                                           2)
                                                                  35MPa.
Notes:
1) The yield strength lower limit value of the clad steel and strip can also be calculated with the following
formula (1):




                                                              9
             t1σs1 − t2σs2
      σs =___________..........................................................................................(1)
                t1 − t2
where, σs1 ____ the cladding metal yield strength standard lower limit value, MPa;
        σs2 ____ the base metal yield strength standard lower limit value, MPa;
        t1 ___ the cladding metal thickness, mm;
        t2 ___ the base metal thickness, mm.

2) The tensile strength lower limit value of the clad steel and strip can also be calculated with the following
formula (2):
              t2σb 1 − t2σb 2
        σb =___________ ………………………………………………………(2)
                t1 − t2
where: σb 1____ the cladding metal tensile strength standard lower limit value, MPa;
        σb 2____ the base metal tensile strength standard lower limit value, MPa;
        t1 ___ the cladding metal thickness, mm;
        t2 ___ the base metal thickness, mm.

3) In the event that the cladding metal elongation standard value is less than that of the base
metal, and the clad steel plate elongation is less than that of the base metal, but no less than the
standard value of the cladding metal, tensile test shall be only made to the base metal layer, and
not to the cladding metal layer, and the resulting elongation shall be no less than the standard
value as required for the base metal layer

4) No impact test shall be required for the cladding metal layer of the clad steel plate.



6.4 Cold bending property
The test conditions and test results of the bending test for the clad steel plate and strip
shall be in accordance with the requirements as indicated in the following Table 8.

Table 8 Bending test for the clad steel plate
Thickness          Specimen           Bending            Bending         test      mandrel                Test result
                   width              angle              diameter
   mm                mm                                  Internal            External             Internal           External
                                                         bending             bending              bending            bending
 ≤25               b = 2a                180º            a<20mm,             a<24mm,              The outside surface of
                                                         d=2a;               d=2a;                the bend section of the
                                                         a≥20mm,             a≥24mm,              specimen shall be free of
                                                         d=3a                d=3a                 any crack, while no




                                                                 10
 >25           b= 2a             180º         Get the base    Get the base    lamination shall be found
                                              metal layer     metal layer     at the cladding line.
                                              machined to     machined to
                                              25 mm , and     25mm , and
                                              the bending     the bending
                                              mandrel         mandrel
                                              diameter as     diameter as
                                              per       the   per       the
                                              specification   specification
                                              for the base    for the base
                                              plate.          plate.
Note: a is the total thickness of the clad steel plate.


6.5 Surface quality
The surface of the cladding metal layer of the clad steel plate shall be free of any
porosity, scar, crack, inclusion, and folding, etc. In case of any of these defects, it shall
be allowed to be removed. The cleaned defect area shall be within the minimum
thickness range of the cladding meal layer as required, otherwise proper weld-repair
shall be further required. The surface quality of the base metal layer shall be in
accordance with relevant requirements as specified in the applicable specification for
the base metal.

6.6    Intergranular corrosion test for the cladding metal layer
Intergranular corrosion test shall be made by the supplier to the cladding metal layer
of the clad steel plate as per Standard GB/T 3280 and Standard GB/T 4237. Only after
the cladding metal is qualified via the intergranular corrosion test, should it undergo
the cladding process. As for the base metal of the clad steel plate, if requested by the
customer, intergranular corrosion test can be made as per applicable specification for
the base metal.

6.7 Furnishing conditions
Before being furnished, the final clad steel plate shall be properly heat treated, and the
cladding layer surface shall be additionally treated with such processes as pickling,
passivation or polishing. With agreement between the supplier and the customer, the
clad steel plates shall be allowed to be furnished under as-rolled conditions. For 4 mm
~ 8 mm thick hot-rolled clad steel strips, pickling treatment shall not be mandatory.

7     Acceptance inspection procedures
7.1 Inspection items
The inspection items for the clad steel plates and strips are indicated in the following
Table 9.

(To be continued)



                                                    11
Table 9 Inspection items for clad steel plates
             Class                                           Explosive clad steel plates
                                            Class I                   Class II               Class III
                                            BI                        BII                    BIII
Inspection items                            BRI                       BRII                   BRIII
                                            RI                        RII                    RIII
     Tensile test                          〇                          〇                      〇
     External bending test                 △                          △                      △
     Internal bending test                 〇                          〇                      〇
     Shear strength test                   〇                          〇                      〇
     Impact test                           〇                          〇                      △
     Ultrasonic detection                  〇                          〇                      〇
     Intergranular                         △                          △                      △
      corrosion test
     Dimensions                            〇                          〇                      〇
     Surface quality                       〇                          〇                      〇
     Cladding layer thickness              〇                          〇                      〇


Legend: 〇 __ mandatory inspection item;
         △__ customer-requested inspection item


7.2 Specimen quantity and testing methods
The specimen quantity and testing methods for the clad steel plates and strips are
indicated in the following Table 10.

Table 10       Sampling and testing methods
Serial No.    Inspection item           Specimen                 Sampling method            Testing method
                                        quantity
1             Tensile test                  1              GB 2978                          GB/T 6396
2             External bending test         1              GB 2975, GB/T 6296               GB/T6396
3             Internal bending test         1              GB 2975,GB/T 6396                GB/T 6396
4             Shear strength test           2              GB/T 6396                        GB/T 6396
5             Impact test                   3              GB/T 2975                        GB/T 229
6             Ultrasonic detection      piece-by-piece     Longitudinal   detection   for   Appendix A of this
                                                           each lot                         standard
7             Intergranular corrosion       2                                               GB 4334.3,
              test                                                                          GB 4334.5
8             Dimensions                piece-by-piece


                                                      12
9           Surface quality           piece-by-piece
10          Cladding          layer       2
            thickness


7.3 All the inspections and acceptance of the clad steel plates and strips shall be
done by the quality control department of the supplier (manufacturer).

7.4 Requirements for lot-composition
Any clad steel plates or strips shall be delivered in lots. Each individual lot shall
consists clad steel plates or strips as produced with the same manufacturing process
and the same heat treatment process. For any lot of clad steel plates or strips of
Premium Class or Class I, the cladding metal and the base metal of each piece shall be
of the same material respectively, i.e., the same grade, heat No. and size. And for any
lot of clad steel plates or strips of Class II, the cladding metal and the base metal of
each piece shall be of the same material respectively, i.e., the same grade and size.

7.5 Re-test
In case of failure of any of the tests as made to any lot of clad steel plates or strips,
re-tests shall be made with doubled number of the specimens taken from the same lot.
(The repeat of impact test shall be made as per applicable standard) If any of the
targeted values resulting from the re-tests fails, the lot shall be rejected. However in
such a case, it shall be allowed to conduct piece-by-piece sampling and tests and thus
make the delivery on a piece-by-piece basis.

8 Packaging, identification and quality certification
8.1 Packaging, identification and quality certification of the clad steel plates or
strips shall be in made in accordance with relevant requirements as specified in
Standard GB/T 247.
8.2 In addition, the packaging, identification and quality certification of the clad
steel plates or strips shall be also in compliance with the following requirements:
8.2.1 The clad steel plates or strips shall be properly packaged in such a manner
that any damage of the cladding plate surface by scratch or scoring can be avoided.
8.2.2 Product identification of clad steel plates or strips shall be marked on each
piece, and for all the pieces, the mark shall be made at a fixed same location.
The product identification shall contain the following information:
a) Lot No.;
b) Grade: Cladding steel grade + base steel grade;
c) Size: ( cladding plate thickness + base plate thickness ) + width + length;
b) Manufacturing process and the weld-on condition of the cladding line;
d) Applicable standard No.;
g) Trade mark and Manufacturer
j) Manufacture date (Mon., day, year)




                                                   13
Appendix A (an appendix of this standard)


The ultrasonic inspection method for stainless steel clad plate

A1 Scope
This inspection method shall be applicable for the ultrasonic detection of the stainless
steel clad plate for pressure vessels to determine the joint conditions thereof.

A2 General requirements
A2.1     Inspection personnel
Any person involving the ultrasonic inspection of the clad steel plate shall be
qualified via proper technical training and certified for the qualification of relevant
NDT inspector. The inspector to sign/issue the inspection report shall be qualified as
Class I or Class II.
A2.2     Inspection equipment
The A type pulse-reflection soniscope shall be used. The soniscope shall be in
accordance with relevant provisions of Standard ZBY230.
A2.3 Sensor
Diameter: 20 ~ 30 mm, frequency: 2.5 ~ 5MHz.
A2.4 Contact type
Direct contact method or water immersion method.
A2.5 Couplant
Couplant with good acoustical transparency and no harm to the material surface like
machine oil, glycerin or water should be used.
A2.6 Surface to be detected
The surface to be detected shall be free of any dirty matters which may negative
influence the inspection effectiveness such as scale, greasy residue or rusty spot, etc.
A2.7 Scanning speed
The scanning speed of the sensor shall be no higher than 150mm/s, unless scanning
with auto-warning function is adapted.

A3 Detection time
Only after the clad steel plate has undergone all the necessary processes namely,
cladding, heat treatment, leveling, shearing or cutting off, should the ultrasonic
detection be conducted.

A4 Inspection procedure
The bottom-wave reflection method shall be adapted.


                                           14
A5 Inspection surface
In general the detection shall start with the surface of the cladding metal layer.
However where necessary, the detection shall be allowed to start with the surface of
the base metal layer.

A6 Detection sensibility
The detection sensibility shall be adjusted by the clad steel plate being tested. The
setting shall be done by means of locate the sensor at the fully jointed area of the plate
and get the first bottom wave amplitude up to 80% of the full scale on the screen.

A7 Detection of the un-jointed area
The so called un-jointed area means an area which has produced the first bottom wave
amplitude no more than 5% of the full scale on the screen and a defect wave
amplitude more than 5% of the full scale on the screen. Get the sensor from the
un-jointed area move around till the bottom wave amplitude is up to 40% of the full
scale on the screen. Then take the sensor as the center to identify the border line of the
said un-jointed area. Mark all the un-jointed areas, and make the record.

A8 Joint rate
The joint rate shall be determined through the following formula:

               S  S1
          J=          x100%
                 S
  where: j __ joint rate (%);
         S__ area of the clad steel plate, in cm2;
         S1__ total area of the un-jointed area, in cm2.

A9 Inspection report
The ultrasonic test report of the clad steel plate shall include the information as
specified below:
     __ the authorized inspection institution; No. of the report;
     __ Grade and thickness of the cladding metal and those of the base metal;
     __ Class code, Lot No., Plate serial No. and size;
     __ Type, sensor diameter & frequency and couplant of the detector
     __ applicable standard;
     __ the test conclusion, including a sketch indicting the location, profile and
         dimensions (length & area) of the un-jointed area, the joint rate value and
         evaluation of each as-tested plate made as per applicable standard, i.e., OK or
         not.
     __ Inspection date
     __ signatures of the inspector and the reviewer

                          (The end )


                                            15

				
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