Iranian Classification Society Rules

Section 2-3 Rolled Steels intended for welding with high heat input

221. Application

The requirements in this Section specifies the weldability confirmation scheme of normal and higher strength hull structural steels intended for welding with high heat input over 50kJ/cm. The weld- ability confirmation scheme is to be generally applied by manufacturer's option.

222. Data to be submitted

The following reference data in addition to those specified in 102. are to be submitted to the Society.

(1) Outline of steel plate to be certified

(a) grade and thickness range

(b) deoxidation practice and fine grain practice

(d) aim maximum Ceq and Pcm

(e) production statistics of mechanical properties (tensile and Charpy V-notch impact tests), if any

(2) Manufacturing control points to prevent toughness deterioration in heat affected zone when weld- ed with high heat input, relevant to chemical elements, steel making, casting, rolling, heat treat- ment etc.

(3) Welding control points to improve joint properties on strength and toughness, if any.

223. Approval tests

1. Test plate and Test assembly

(1) Test plate is to be manufactured by a process approved by the Society in accordance with the requirements in Section 2-1. For each manufacturing process route, two test plates with differ- ent thickness are to be selected. The thicker plate (t) and thinner plate (less than or equal to t/2) are to be proposed by the manufacturer.

(2) One butt weld assembly is to be generally prepared with the weld axis

transverse to the plate

rolling direction. Dimensions of quired test specimens.

2. Welding of test assembly

(1) The welding procedures should applied at shipyards for the test

the test assembly are to be amply sufficient to take all the re-

be as far as possible in accordance with the normal practices plate concerned.

(2) Welding process, welding position, welding consumable (manufacturer, brand, grade, diameter

and shield gas) and welding parameters including bevel preparation, heat input, preheating tem- peratures, interpass temperatures, number of passes etc. are to be reported.

3. Approval test and acceptance criteria

Approval test items, test methods and acceptance criteria are to be as given in Table 2.2.5.

4. Additional test assemblies and/or test items may be required in the case of newly developed type of steel, welding consumable and welding method, or when deemed necessary by the Society.

Where the content of tests differs from those specified in firmed by the Society before the tests are carried out.

5. Other test

Additional tests such as wide-width tensile test, HAZ

Table 2.2.5, the program is to be con-

tensile test, cold cracking tests (CTS,

Cruciform, Implant, Tekken, and Bead-on plate), CTOD or other tests should be required discretion of the Society.

at the

224. Grade designation

(1) Upon issuance of the certificate, the notation indicating the value of heat input applied in the confirmation test may be added to the grade designation of the test plate, e.g. "EH 36-W 300" (in the case of heat input 300 kJ/cm applied).

(2) The value of this notation is to be not less than 50 and every 10 added.

Guidance for Approval of Manufacturing Process and Type Approval, Etc. 2015 17

Ch 2 Approval of Manufacturing Process Ch 2, Sec 2-3

Table 2.2.5 Weldability confirmation test Items, test methods and acceptance criteria

Test items

Direction of the test specimens

Test method

Acceptance criteria

Visual examination

Overall welded surface should be subject to visual examination.

Overall welded surface is to be uniform and free from injurious defects such as cracks, undercuts, overlaps etc.

Macro structure tests

A sketch of the weld joint depicting groove dimensions, number of passes, hardness indentations should be attached to the test report together with photo-macrographs of the weld cross section.

To be free from crack, incomplete penetration, lack of fusion, other harmful defects

Microscopi c test

Along mid-thickness line across transverse section of the weld, one micrograph with x100 magnification is to be taken at each position of the weld metal centreline, fusion line and at a distance 2, 5, 10 and minimum 20mm from the fusion line.

The test result is provided for information purpose only.

Hardness test

Along two lines across transverse weld section 1mm beneath plate surface on both face and root side of the weld, indentations by Hv5 are to be made at weld metal centreline, fusion line and each 0.7mm position from fusion line to unaffected base metal (minimum 6 to 7 measurements for each heat affected zone).

The maximum hardness value should not be higher than 350Hv.

Transverse tensile test

Two transverse (cross weld) tensile specimens are to be taken from the test assembly. Test specimens and testing procedures are to comply with the requirements of PT 2

The tensile strength is to be not less than the minimum required value for the grade of base metal.

Bend test

Two transverse (cross weld) test specimens are to be taken from the test assembly and bent on a mandrel with diameter of quadruple specimen thickness. Bending angle is to be at least 120°. Test specimens are to comply with the requirements of PT 2.

For plate thickness up to 20mm, one face-bend and one root- bend specimens or two side-bend specimens are to be taken. For plate thickness over 20mm, two side-bend specimens are to be taken.

After testing, the test specimens shall not reveal any crack nor other open defect in any direction greater than 3mm.

Impact test

(a) Charpy V-notch impact specimens (three specimens for one set) are to be taken within 2mm below plate sur- face on face side of the weld with the notch perpen- dicular to the plate surface.

(b) One set of the specimens transverse to the weld is to be taken with the notch located at the fusion line and at a distance 2, 5 and minimum 20 mm from the fusion line.

(c) The fusion boundary is to be identified by etching the specimens with a suitable reagent. The test temperature is to be the one prescribed for the testing of the steel grade in question.

(d) For steel plate with thickness greater than 50mm or one side welding for plate thickness greater than 20mm, one additional set of the specimens is to be taken from the root side of the weld with the notch located at each the same position as for the face side.

(e) Additional tests at the different testing temperatures may be required for evaluating the transition temperature curve of absorbed energy and percentage crystallinity at the discretion of the Classification Society.

The average impact energy at the specified test temperature is to comply with the requirements of PT 2 depending on the steel grade and thickness. Only one individual value may be below the specified average value provided it is not less than 70% of that value.

18 Guidance for Approval of Manufacturing Process and Type Approval, Etc. 2015

Ch 2 Approval of Manufacturing Process Ch 2, Sec 2-4

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