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Reg. 98
MATERIALS OF CONSTRUCTION

COVERED ELECTRODES FOR METAL ARC WELDING OF MILD STEEL

Periodic Check Test.-

The following Periodic Check Tests on each brand of electrodes shall be carried out:-

(a) Periodic check tests consist of a selection of the tests prescribed under Regulations 95 and 97 and they shall be repeated at intervals of not more than 6 months to provide evidence that the electrodes currently produced continue to possess the properties recorded in the initial tests.

(1) All-weld tensile test with any two sizes of electrodes within the limits prescribed in clause (a) of Regulation 95.

(2) One Tee joint fillet weld hot cracking test as prescribed in clause (b) of Regulation 95.

(b) For deep penetration butt-welding electrodes, one transverse tensile test specimen and two transverse bend test specimens shall be prepared and tested as prescribed in Regulation 96 and the specimens shall show that a complete penetration has been achieved.

(c) For deep penetration fillet welding electrodes one cruciform fillet weld tensile test shall be taken as prescribed in Regulation 97(1) and the two outer discards from the test pieces shall show a minimum penetration beyond the root as required under Regulation 97(2).

APPENDIX H-1 (See Regulation 95)

(1) Parent Metal for Test Plates.- The parent metal used in preparing test pieces and test specimens shall be mild steel of welding quality in the normalized condition (this condition is optional in the case of all-weld metal tests) with an ultimate tensile stress of not less than 28 and not more than 32 tons per square inch and an elongation of not less than 20 per cent on standard test piece A(1) (Appendix B).

(2) All-Weld Metal Test.- Method of preparation of test pieces. The temperature of the parent metal shall be between 50° and 100°F (10° - 38°C) immediately before depositing the first run of weld metal. The test specimen shall not be subjected to any mechanical or thermal treatment other than that required herein. All-weld test pieces shall be prepared as shown in Figure 1* by depositing weld metal between the chamfered edges of two plates, each 7/8 inch thick. The preparation of the plates shall give an included angle of 20° and the distance between the plates at the root edges shall be ½ inch to 17/32 inch. The joint shall be closed at the bottom by a backing pipe 1¼ inch wide by ¼ inch thick. The two plates shall be 7 inches long and the dimension B from square edge to root edge of each side plate shall be between:

2 inches minimum and 3 inches maximum when testing 12 S.W.G. (3/32) inch electrodes.

*As shown in this Appendix.
3 inches minimum and 4 inches maximum when testing 10 S.W.G. or 8 S.W.G. electrodes.
4 inches minimum and 5 inches maximum when testing 6 S.W.G. electrodes.
5 inches minimum and 6 inches maximum when testing ¼ inch or 5/16 inch electrodes.

The assembly shall be welded together with these plates pre-set so that the gap at the top between the chamfered edges of the plates is 1 inch and the plates may be approximately level when the butt-weld is completed.

The weld metal shall be deposited in single or multi-run layers and the direction of deposition of each layer shall be alternatively from each end of the specimen. Each run of weld metal shall not be less than 1/16 inch and not more than 1/8 inch thick. The time interval between the completion of one run and the commencement of deposition of the succeeding run shall be not less than 5 minutes. The assembly shall not be quenched between the deposition of individual runs. The welding current used shall be within the appropriate range given by the manufacturer. The welding position for the assembly shall be flat, unless this is contrary to the recommended position for the electrode, in which case the position of weld shall be as recommended by the manufacturer.

On completion of the weld the specimen shall be allowed to cool in still air. The portion including the weld shall then be removed by cutting away the excess plate at the places indicated in Figure 1.

The all-weld test piece shall be heat-treated by raising to a uniform temperature of 1112° to 1202°F (600° to 650°C) and maintained at that temperature for one hour and then allowed to cool slowly outside the furnace, protected from draughts and chilling. A tensile test specimen shall be machined from the test piece to the dimensions given in Figure 1(a)* taking care that the longitudinal axis of the specimen coincides with the centre line of the weld and the mid-thickness of the plate as indicated in Figure 1. The specimen then shall be tested for tensile strength.

(3) Impact Test Specimen.- The Izod impact test specimens shall be machined from the weld metal test pieces to the dimensions given in Figure 2,* care being taken that the longitudinal axis of the test piece coincides with the centre line of the weld and mid-thickness of the plate. The temperature of the test specimen at the time of testing shall not be less than 50°F (10°C).

(4) Hot Cracking Test.- A 6 inches x 4 inches x ½ inch plate shall be welded to a second plate 6 inches x 6 inches x ½ inch in the form of a close square Tee joint as shown in Figure 3*. The edge of the first plate abutting the surface of the second shall be prepared by machining or grinding. The gaps between parts after tack welding at the ends shall not exceed 0.01 inch.

_________________________________________________*As shown in this Appendix.

Two fillet welds 5 inches long and ¼ inch in leg length shall be deposited in the flat position with a single 6 S.W.G. (or 0.2 inch) electrode, using the maximum current of the range recommended by the manufacturer. The test piece shall be so positioned that the slope and the rotation of the weld are zero. The second weld shall be started at that end where the first run was finished after time interval of 4 to 5 seconds. The slag shall be removed after the test piece is cooled in still air to the room temperature. The surfaces of the weld shall be visually examined for cracks.

The second plate shall be slit and the welds broken open as shown in Figure 4*. The weld shall not show any evidence of hot cracking as indicated by oxidation or temper colouring of the surface of the fractures.

(5) Transverse Tensile and Bend Tests.- The transverse tensile and bend test pieces shall be made as shown in Figure 5* by butt-welding together two ½ inch plates of suitable length and not less than 6 inches in width. The Plate edges shall be prepared to form a single Vee joint the details of which shall be as follows:-

(See Figure 5a)*
Angle between fusion faces 60° - 70°.
Root face 1/8 inch.
Maximum gap 1/8 inch.

The plate edges shall be prepared as per Figure 5(a)*, and pre-set to allow for slight distortion after welding.

The welding procedure in making out the test pieces shall be according to the position of welding as in Table 1 below:-______________________________________________________*As shown in this Appendix.

TABLE 1
Welding procedure for preparation of transverse tensile test and bend test pieces

Welding position for test pieces (all angles±5°) as shown in Table-5 below

Welding Procedure
FLAT
Weld slope 0°
Weld rotation 180°
1. All runs made with 8 S.W.G. electrodes.

2. First run – 6 S.W.G. electrodes. Subsequent runs – 5/16 inch diameter electrodes (or largest size manufactured).

INCLINED
Weld slope 30°
Weld rotation 45
Weld slope 30°
Weld rotation 45
First run – 8 S.W.G. electrodes. Subsequent runs – 6 S.W.G. electrodes.
HORIZONTAL-VERTICAL
Weld slope 0°
Weld rotation 90°
First run – 8 S.W.G. electrodes. Subsequent runs – 6 S.W.G. electrodes.
VERTICAL
Weld slope 90°
All runs made with 8 S.W.G. electrodes.
OVER HEAD
Weld slope 0°
Weld rotation 180°
All runs made with 8 S.W.G. electrodes.

 

In all cases a backing run shall be made with 8 S.W.G. electrodes in the welding position applicable to the test piece, after cutting out a groove of 1/8 inch deep if considered necessary, as in Figure 5(a)*.

The test pieces for the inclined and vertical positions shall be welded using the ‘upwards’ method unless the electrodes manufacturer specifically recommends that only the ‘downwards’ method shall be used. If both methods are recommended, test pieces welded by each method shall be made.

After welding, the test pieces shall be cut by sawing on machine to form one transverse tensile, one face-bend and one root-bend test specimen, as indicated in Figure 5*.

(6) Transverse Tensile Test.- Transverse tensile test specimens shall conform to the dimensions given in Figure 6*. The upper and lower surfaces of the weld shall be filed, ground or machined level with the respective original surfaces of the plates. Where the surfaces of the plates are not level with each other the metal may be cut away to bring them approximately level, provided that the thickness of the plate is not reduced by more than a total of 0.04 inch.

_________________________________________________*As shown in this Appendix.

The test specimens shall then be tested for tensile test as in Appendix-B.

(7) Transverse Bend Test.- The bend test specimens shall be 1½ inches in width. The upper and lower surfaces of the weld shall be filed, ground or machined level with the respective original surfaces of the plates, with the proviso as in item (6) above. Tool marks should be avoided as they lead to location of stress and may cause premature failure. For this reason the direction of machining of the surfaces should be along the specimens and transverse to the weld. The sharp corners of test specimens shall be rounded to a radius not exceeding 1/20 inch.

The test specimens shall be bent through an angle of 180° over former having a diameter equal to three times the thickness of the specimen, as shown in Figure 7*. One test specimen shall be tested with the face of the weld in tension and one with the root of the weld in tension.

(8) Cruciform Fillet Weld Tensile Test - Normal Penetration Electrodes.- The specimens shall be prepared as shown in Figure 8*. Care shall be taken that the centre lines of two vertical plates are in the same plane. The parent metal used shall be at a temperature between 50° - 100°F (10° - 38°C) immediately before depositing the first run of weld metal. The test specimens shall not be subjected to any mechanical or thermal treatment, other than what is given in this appendix. The plates shall be so placed that each weld shall be deposited in the appropriate welding position, using the procedure specified in Table 2 below:-

TABLE 2

Welding procedures for preparation of Cruciform fillet weld tensile test pieces for normal penetration electrodes

Welding position for test pieces (All angles ±5°) as shown in Table 5 below.


Welding Procedure
FLAT
Weld slope 0°
Weld rotation 0°
One run – 4 S.W.G. or 5/16 inches diameter electrodes.
INCLINED
Weld slope 30°
Weld rotation 90°
Not more than 3 runs – 8 S.W.G. electrodes.
HORIZONTAL – VERTICAL
Weld slope 0°
Weld rotation 45°
FNot more than 3 runs – 6 S.W.G. or 4 S.W.G. electrodes.
Vertical Weld slope 90° One run – 8 S.W.G. electrodes.
OVERHEAD
Weld slope 0°
Weld rotation 180°
Not more than 3 runs – 8 or 6 S.W.G. electrodes.

______________________________________________________________

*As shown in this Appendix.

The welding current used shall be as per recommendation of the manufacturer.

The test pieces for the inclined and vertical positions shall be welded using ‘upwards’ method, unless the manufacturer specifically recommends ‘down-wards’ method. If both methods are recommended, test pieces welded by each method shall be made. The completed test piece shall be cut into strips by sawing or machining as shown in Figure 8* and the inner strip tested in tension as indicated therein.

__________________________________________________*As shown in this Appendix.

APPENDIX H-2
(See Regulation 96)

Butt-Weld Tests.- Deep Penetration Electrodes.

The parent metal shall be at a temperature between 50° and 100°F (10° - 38°C) immediately before depositing the first run of weld metal and the test specimen shall not be subjected to any mechanical or thermal treatment other than that specified in this Appendix. The test pieces shall be made by welding together two plates not less than 6 inches wide and of the thickness specified in Table 3 below:

TABLE 3

Welding procedure for preparation of butt-weld test Pieces Deep Penetration Electrodes

Welding position for test pieces (All angles +5°) as shown in Table 5 below
Welding Procedure
FLAT

Weld slope 0°

Weld rotation 0°

1. One run on each side of joint with the largest size of electrode manufactured. Plate thickness equal to twice diameter of the core wire or ½ inch (whichever is less).

2. One run on each side of joint with the smallest size of electrode manufactured (but not less than 1/8 inch diameter). Plate thickness equal to at least twice diameter of the core wire.

3. One run on each side of joint with ¼ inch diameter electrodes. Plate thickness not less than ½ inch.

The length of the plates shall be sufficient to accommodate on one side the run length of a complete electrode, but in any case shall not be less than 10 inches.

The joint edges of the plates shall be square cut and any gap between the plates after tack welding at the ends shall not exceed 0.010 inch.

The welding procedure shall be as set out in the above table and in addition the first electrode used for welding each side shall be consumed for its full length except for a stub end of not more than 2 inches. The welding current used shall be as recommended by the manufacturer and each weld shall be deposited in the flat welding position and started as shown in Figure-9.*

*As shown in this Appendix.

Each test piece shall be so marked that the side first welded remains identifiable after the test specimens have been cut out, as shown in Figure- 9*. The specimens shall be cut out by sawing or machining to provide one tensile test specimen and two transverse bend test specimens. The two outer discards shall be retained and their inner edges shall be prepared and etched to reveal weld metal one as required for the butt-weld penetration test.

(1) Transverse Tensile Test.- Transverse tensile test specimen shall conform to the dimensions given in Figure 6y for such specimens and where the surfaces of the plates are not, level they shall be made so by machining or filling provided the thickness of the plate is not reduced by more than a total of 0.04 inch. The specimen shall then be tested for tensile test.

(2) Transverse Bend Test.- Each transverse bend test specimen shall be of a width equal to three times its thickness. The upper and lower surface of the weld shall be filed, ground or machined level with the respective original surface of the plates provided the thickness of the plates is not reduced by more than a total of 0.04 inch. The direction of machining of the surfaces shall be along the specimen and transverse to the weld. Tool marks shall be avoided to eliminate premature failure, and the sharp corners rounded to a radius not exceeding one-tenth the thickness of the specimen. The test specimen shall be bent through an angle of 180° over a former having a diameter equal to three times the thickness of the specimen as shown in Figure 10*. One test specimen shall be tested with the side first welded in tension, and one with the other side in tension.

(3) Cruciform Fillet Weld Test - Deep Penetration Electrodes.- The parent metal shall be at a temperature between 50° and 100°F (10° - 38°C) immediately before depositing the first run of weld metal. The test specimen shall not be subjected to any mechanical or thermal treatment other than that specified in this Appendix.

For each test piece, two pieces of plate, of sufficient length to suit the testing machine shall be welded to a third plate by means of fillet welds as shown in Figure 11*. Care shall be taken that the centre lines of the vertical plates are in the same plane. The width of the plates shall be sufficient to accommodate on one side the run length of complete electrode, but in any case shall be not less than 10 inches. The thickness of each piece of plate shall be as specified in Table 4 below.

The edge of each vertical plate abutting the surface of the horizontal plate shall be square cut prepared by machining, grinding or gas cutting), and any gap between the horizontal plate and the vertical plates, after tack welding at the ends in preparation for welding shall not exceed 0.01 inch.

*       As shown in Appendix.
Y     As shown in Appendix H-1.

The welding procedure followed in making the test pieces shall be as set out in Table 4 below with the addition that the first electrode used for welding each fillet shall be consumed for its full length except for a stub end of not more than 2 inches.

TABLE 4

Welding procedure for preparation of cruciform fillet weld test pieces (deep penetration electrodes)

Welding position for test pieces (as shown in table 5 below) all angle ±5°
Welding Procedure

 

 

 

HORIZONTAL – VERTICAL

Weld slope 0°

Weld rotation 45°

 

1. One run on each side of each joint with the largest size of electrode manufactured. Plate thickness equal to at least twice diameter of the core wire or ½ inch (whichever is less). Maximum fillet leg length shall be 1/8 inch less than the plate thickness.

2. One run on each side of each joint with the smallest size of electrode manufactured (but not less than ½ inch diameter), Plate thickness equal to at least twice diameter of the core wire. Maximum fillet leg length shall be 1/8 inch less than the plate thickness.

3. One run of each side joint with1/4 inch diameter electrodes. Plate thickness not less than1/2 inch and fillet leg length not to exceed 3/8 inch.

The welding current used shall be within the appropriate range recommended by the manufacturer and each weld shall be deposited in the horizontal-vertical position.

The order of laying down fillets shall be as indicated by the numbers 1, 2, and 4 in Figure 11*. The adjacent fillet shall be laid in opposite directions. After welding the test piece shall be cut by sawing or machining as indicated in Figure 11* and the inner edges of the two outer discards shall be prepared and etched as specified for the cruciform fillet weld tensile tests for normal penetration electrodes in Appendix H-1.

The test specimen shall then be tested for tensile test.

*As shown in this Appendix.

WELDING POSITIONS ARE DEFINED AS FOLLOWS:

POSITIONS
SLOPE
ROTATION
SYMBOL
ILLUSTRATION
FLAT
NOT EXCEED-ING 10°
NOT EXCEED-ING 10°
F
FIG.4
INCLINED
EXCEED-ING 10° NOT

EXCEED-ING 45°

NOT EXCEED-ING 90°
I
FIG.5
HORIZON-TAL VERTICAL
NOT EXCEED-ING 10°
EXCEED-ING 10° NOT EXCEED-ING 90°
H
FIG.6
VERTICAL
EXCEED-ING 45°
ANY
V
FIG.7
OVERHEAD
NOT EXCEED-ING 45°
EXCEED-ING 90°
O
FIG.8

NOTE: THE FIVE POSITIONS DEFINED ABOVE COVER ANY POSSIBLE COMBINATION OF SLOPE AND ROTATION SO THAT EVERY WELD CAN BE CLASSIFIED IN ONE OF THESE POSITIONS.

 
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