Examination Of Welders
These Regulations shall apply to testing of welders engaged in India in the manufacture and site welding connected with the erection and fabrication of boilers and steam-pipes of ferrous material.
“WELDER” means a person engaged in manual welding (gas or electric).
ENGAGING OF CERTIFIED WELDERS
No welder shall be engaged on welding of boilers or steam pipes under construction, erection or fabrication at site or in the repair of boilers or steam pipes, unless he posses a certificate as required under the regulations herein after contained.
INITIAL QUALIFICATION TEST & ISSUE OF CERTIFICATE
Every welder shall be duly tested & qualified to the satisfaction of the competent authority who shall assess his performance for qualifying for the certificate. The competent authority may, thereafter, issue a certificate in FORM XIII indicating the class and type of welding in which he has qualified.
AGE AND EXPERIENCE
This regulation deals with age and experience of a candidate wishing to qualify for a certificate under these regulations to the satisfaction of the competent authority. A candidate who wishes to qualify for a certificate under these regulations shall not be less than eighteen years of age and shall have undergone a regular apprenticeship of two years in Industrial Training Institutes or an industrial organization followed by at least one year regular on-job experience as a welder in a workshop or industry.
TEST FOR INITIAL QUALIFICATION OF A WELDER
(A) Theoretical Examination:- A welder shall be required to answer questions on the following subjects orally or otherwise :-
1. Electric Welder :-
- Weld preparation.
- Elementary knowledge of the working of welding equipment.
- Properties of material to be welded-cold and hot working, thermal conductivity, fusion point, oxidation (for welders engaged in alloy steel welding).
- Elementary knowledge of electro-technical principles - kinds of current striking are voltage, welding-are voltage.
- Welding defects and their prevention-influence of length of electric are effect of excessive or too low amperage, slag inclusion porosity finishing the surface of welding bead.
- Electrodes for different types of welds and steels and joints in different positions.
2. Gas Welder :-
- Weld preparation.
- Working of welding equipment.
- Elementary knowledge of properties of materials to be welded-cold and hot working, thermal conductivity, fusion point, oxidation (for welders engaged in alloy steel welding).
- Elementary knowledge of fuel gas and flame adjustments for favorable welding condition.
- Kinds of welds, welding defects and their prevention, welding technique (right-ward and left-ward), welding with two torches on vertical surface, excess of gas or oxidation, pre-heating of base material and subsequent heat treatment.
- Filler metals.
(B) A welder shall be required to undergo and pass the following practical tests.
1. Material for tests:-
The material of Plates, tubes, pipes and electrodes used for these tests shall conform to the requirements of appropriate Regulations as may be applicable in each case.
2. Test welds for initial qualification (Electric or Gas). -
(a) Plate welding -
(i) One groove welded joint of two pieces of plates with double V or Double U grooves on boiler quality plates over a length of 381 mm (15 inches) in the following positions (size of plates to be welded being not less than 229 mm. X 381 mm X16 mm. (9” X 15” X 5/8” each):-
- Flat Position XIII/6 - Plate in a horizontal plane with the weld metal deposited from above.
- Horizontal Position XIII/7- Plate in a vertical plane with the axis of the weld horizontal.
- Vertical Position XIII/8 - Plate in a vertical plane with the axis of the weld vertical.
- Overhead Position XIII/9 - Plate in a horizontal plane with the weld metal deposited from underneath.
Qualification in position XIII/7 or XIII/8 shall qualify also for position XIII/6
Qualification in position XIII/9 shall qualify for positions XIII/6, XIII/7 and XIII/8 also.
(ii) One fillet welded joint over a length of 381 mm. (15 inches) using plate not less than 16mm. (5/8 inches) in the following positions :-
- Flat Position XIII/10 - Plates so placed that the weld is deposited with its axis horizontal and its throat vertical.
- Horizontal Position XIII/11 - Plates so placed that the weld is deposited with its axis horizontal on the upper side of the horizontal surface and against the vertical surface.
- Vertical Position XIII/12 - Plates so placed that the weld is deposited with its axis horizontal on the under side of the horizontal surface and against the vertical surface.
Qualification in position XIII/11, or XIII/12 shall qualify for position XIII/10
Qualification in position XIII/12 shall qualify for positions XIII/10, XIII/11 and XIII/12.
b) For pipe Welding :-
(1) One test on groove weld joint for each of the following welding positions:
(i) Horizontal Rolled -
Pipe with its axis horizontal and rolled during welding so that the weld metal is deposited from above with the axis of the weld horizontal
(ii) Horizontal Turned -
Pipe with its axis horizontal the upper half welded first, the pipe then being turned through 180 degree and the other half then welded.
(iii) Vertically fixed -
One test of groove welded joint with the axis of the pipe in a vertical position and the seam welded circumferentially in a horizontal position.
(iv) Horizontal fixed -
One test of groove welded joint with the axis of the pipe in a horizontal position and the seam welded without rotating the pipe.
Qualification in positions (ii) or (iii) shall qualify also for position (i) qualification in position (iv) shall qualify for position (i) or (ii).
(2) One weld of a branch to a pipe.
The size of pipe to be welded shall be not less than 127 mm. (5 inches) in external diameter and 10mm. (3/8 inch) thick, and a branch pipe shall not be less than 89mm. (3-1/2 inches) Outside diameter and 6mm. (1/4 inch) thick.
*(c) For Tube Welding:-
A butt welded joint of two pieces of boiler tubes with the axis in a vertical position and tubes of same size fixed in adjoining positions. This test shall be in addition to the test for pipe welding under CI. (b).
TEST FOR REQUALIFICATION
At a requalification test a welder need not be examined in theoretical subjects, but he shall be required to qualify in the following practical tests :-
(a) Plate Welding -
A grove - welded joint of two pieces of plates not less than 16mm (5/8 inch) thick over a length of 152mm. (6 inches) in a position 45 degree to vertical size of Plates to be welded being 229 mm. X 152 mm. (9 inches X 6 inches). The main welding is to be carried from the underside only.
(b) Tube Welding -
- A groove welded joint with the axis of the pipe in a horizontal position and without rotating the pipe.
- One weld of a branch to a pipe, as prescribed in Regulation 609.
- Tube Welding:- A butt welded joint of two pieces of boiler tubes with the axis in a vertical position, and tubes of same size fixed in adjoining positions. This test shall be in addition to the test for pipe welding under CI. (b).
- When a welder is continuously engaged on production weld, tests on the work in actual production to the satisfaction of the Competent Authority may be accepted as an alternative to the tests prescribed as above under Cols. (a), (b) and (c).
611.Examinations of Tests Specimens for Initial Qualification Tests
(a) Groove-welded plate specimens.-
The groove-welded plate specimens after welding may be lightly pressed cold to remove any distortion due to welding. The test specimen shall be similarly treated as required for the actua1 production weld.
After visual examination, the welded specimen shall be subjected to X-ray examination in the manner as provided in Regulation 265 (b), provided that this requirement may be waived when the welder is to be engaged on production work where radiographic examination is not required under these Regulations.
Thereafter test pieces shall be marked and cut out in the order shown in Figure XIII/l.
*The bend test specimens (B1 and B2) shall be prepared and tested as per Regulations 261 and 262. In the case of alloy steel specimen, the angle of the bend is to be decided by the competent authority, provided that the angle shall, in no case, be less than 120°.
Two each specimen (EI and E2) shall be prepared, one for micro and the other for macro-examination as per Regulations 265(a).
(b) Fillet Welded plate specimen:-
The dimensions and preparation of the fillet-weld test specimen shall conform to Figure XIII/2. The test specimen shall not contain any visible cracks. It shall be cut transversely to provide a center section. (254 mm.) (10 in.) long and two end sections each approximately (25 mm.) (1 in.) long.
The stem of the 254 mm. (10 in.) center section shall be loaded laterally in such a way that the root of the weld is in tension. The load shall be steadily increased until the specimen fractures or bends flat upon itself. In order to pass the test,-
(1) The specimen shall not fracture, or
(2) If it fractures; the fractured surface shall show no evidence of cracks or incomplete root penetration, and the sum of the lengths of inclusions and gas pockets visible on the fractured surface shall not exceed (51mm) (2in.).
The cut end of one of the end sections shall be polished and etched with a suitable reagent to give a clear definition of the structure of the weld.
In order to pass the test:-
- Visual examination of the cross-section of the weld shall show complete fusion at the root and freedom from cracks.
- The weld shall not have a concavity or convexity greater than 1.6 mm (1/16 in.); and
- There shall be not more than 1.6 mm (1/16 in.) difference in the length of the legs of the fillet.
(c) Groove-and-fillet-welded pipe and tube specimens :-
The groove-welded pipe and tube specimens shall be marked and test-pieces cut out as in figure XIII/3. The test pieces shall be prepared for face bend, root bend and tech test. The pieces shall not be flattened, but tested in their current conditions. The penetration bead may be removed to 0.8 mm (1/32 in.) round of the surface of the material.
Fillet-welded branches shall be tested for:-
- Visual examination- The test welds so obtained shall be visually examined for root penetration, freedom from undercut, deposition of runs, uniformity of surface, shape of profile, smoothness of joints, freedom from cavities and slag, dimensions of weld deposit, quality of weld metal (over-heating, surface cracks, spongy surface, etc.). Any piece showing serious defect shall be rejected.
- Macro examination- Each branch weld test piece shall be sawn as shown in the figure XIII/4 and each portion so produced shall be prepared and etched. The section shall then be examined for degree of fusion, degree of root penetration, absence of non-metallic (slag) inclusions and quality of weld metal. The joint should show good root fusion, complete freedom from basal cracking, and the absence of any, but very minor defects.
(d) Welded Tube Joints :-
A test length approximately 203 mm long shall be cut from the tube with the welded joint disposed approximately at the centre. After visual examination, one test piece not exceeding 13 mm for tubes, 6mm in thickness and below and thrice the thickness of the tube for thickness of over 6mm shall be cut longitudinally. The test piece shall not be less than 76 mm in length on either side of the weld. The slight excess of internal bead may be filled until it is not more than 0.8 mm round on the general surface. The test piece shall then be bent back with the root in tension through 90 degrees round a former of diameter equal to three times the thickness of the tubes. With regard to alloy steel pipes and tubes, the bend test specimen shall be bent without being straightened, but after removal of the weld reinforcement drawn to the level of but not below the surface round a former of diameter 4t and through an angle of 90 degrees. The bending may be carried out by blows or by pressure. Care shall be taken to ensure that the former is so positioned that the weld is maintained at the crown of the bend. The test specimen shall be capable of being bent through 90 degree without signs of failure, although slight premature failure at the edges of a specimen need not be considered a cause of rejection. The opening out of a slight defect due to incomplete root penetration or lack of root fusion need not be considered a cause of rejection, provided the defect has sound metal at the back and on either side of it.
(e) Additional test before rejection :-
Should any of the test pieces tested in accordance with the above sub-regulations fail to meet the specified requirements, one further strip may be cut from the specimen and subjected to the same test. If any test piece does not reach the required standard two further welds shall be made and the procedure in the above sub-regulation repeated. If any of these welds does not reach the required standards, the welder shall be deemed not to have qualified for a certificate.