Volume-II of IV - GAIL

MECON LIMITED
REGD. OFF: RANCHI (BIHAR)
PROCESS & PIPING
DESIGN SECTION
NEW DELHI
TITLE PIPING FABRICATION AND
ERECTION
1.4 Macroscopic Inspection
1.4.1 Preparation
1.4.2 Method
STANDARD SPECIFICATION
SPECIFICATION NO. PAGE 45 OF 62
MEC/S/05/62/06 REVISION 0
Specimens shall be taken from the positions indicated in Fig. 1 of this
specification and shall be prepared in accordance with ASTM E2 and E3.
The width of the macrosection has to be at least three times the width of the
weld. The section is to be prepared by grinding or polishing and etching to
clearly reveal the weld metal and heat effected zone.
Specimens shall be carefully examined under the microscope with a
magnification of at least 25 times. The COMPANY may ask for a macrograph
with 5 times magnification for documentation purposes.
1.4.3 Requirements
Under macroscopic examination, the welded joints shall show good penetration
and fusion, without any defect exceeding the limits stated in the evaluation
criteria of the nick break test.
1.5 Hardness Test
1.5.1 Preparation
The prepared macrosection is to be used for hardness testing using the Vickers
method with 100 N (10 kg) load. Indentations are to be made along traverses
each approximately 1mm below the surface at both side of the weld.
In the weld metal a minimum of 6 indentations equally spaced along the
traverses are to be made. The HAZ indentations are to be made along the
traverses for approximately 0.5mm each into unaffected material, and starting as
close to the fusion line as possible.
One indentation at each side of the weld along each traverse has to be made on
parent metal. Reference is made to fig. 3 of this specification. The indentation
are to be made in the adjacent region as well as on the opposite side of the
macrosection along the specified traverses.