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Reg. 129-A
FURNACES
Welded Joints in Copper Fire Boxes
| (i) Scope |
All welding of Copper plates shall be carried out by
the oxy-acetylene process. The Inspecting Authority
may at his discretion also permit the use of propane,
butane or other suitable fuel gases.
|
| (ii) Parent Metal |
Phosphorus deoxidized arsenical
copper in the fully annealed condition shall only be used
for welded copper fire boxes.
The composition of the copper shall be within the following
limits :-
Phosphorus Deoxidized Arsenical Copper –
- Copper (silver being counted as copper) not less
than 99.20 per cent.
- Antimony not more than 0.01 per cent.
- Arsenic not more than 0.50 per cent and not less than
0.30 per cent. -
- Bismuth not more than 0.003 per cent.
- Iron not more than 0.01 per cent.
- Lead not more than 0.01 per cent.
- Nickel not more than 0.15 per cent.
- Phosphorus not more than 0.10 per cent and not less
than 0.015 per cent
- Selenium not more than 0.02 per cent.
- Tellurium not more than 0.02 per cent.
- Tin not more than 0.01 per cent.
Pieces cut from the parent material after being heated
in hydrogen for ½ hour at 800°C and subsequently
cooled, must show no edge or surface cracking when subjected
to a close bend test as described below.
The test piece AB is bent by steadily applied pressure
or a succession of blows at right angles to the length
AC and flattened close until A assumes the position
indicated by D (see Fig
5A).
TEST PIECE A FOR OXYACETYLENE WELDING OF COPPER
| NOMINAL THICKNESS OF
TEST PIECE |
(i) |
(iI) |
(iii) |
(iv) |
| UPTO BUT
NOT INCLUDING 3/8 INCH |
3/8 INCH
AND THICKER |
| |
INCH |
INCH |
INCH |
INCH |
| WIDTH W |
½
|
1 |
1½
(Max.) |
1½
(Max.) |
GAUGE LENGTH G
|
2 |
4 |
8 |
8 |
| PARALLEL LENGTH (MIN.)
P |
2½ |
4½ |
9 |
9 |
| RADIUS AT SHOULDER
(MAX) R |
1 |
1 |
1 |
1 |
| APPROX. TOTAL LENGTH |
8 |
12 |
18 |
18 |
WHEN THE WIDTH OF THE MATERIAL TO BE TESTED IS INSUFFICIENT
TO PERMIT OF THE PREPARATION OF THE STANDARD TENSILE TEST
PIECE, A PIECE OF THE FULL WIDTH OF THE MATERIAL MAY BE
USED. |
| (iii) Filler Rod |
The filler rod shall be phosphorus
deoxidized non-arsenical copper and shall contain not
more than 0.15 per cent and not less than 0.04 per cent
phosphorus with the optional addition of silicon upto
0.15 per cent and with the optional addition of silver.
The basic copper used for the manufacture of the filler
rods shall either be cathode copper or electrolytic tough
pitch high conductivity copper conforming to the following
chemical compositions respectively.
Chemical Composition of Cathode Copper –
- Copper (silver being counted as copper) not less
than 99.90 per cent.
- Bismuth not more than 0.001 per cent.
- Lead not more than 0.005 per cent.
Total of metallic impurities (excluding silicon, phosphorus
and silver) not more than 0.03 per cent.
Chemical Composition of electrolytic tough pitch high
conductivity Copper –
- Copper (silver being counted as copper) not less than
99.90 per cent.
- Bismuth not more than 0.001 per cent.
- Lead not more than 0.005 per cent.
Total of all impurities (excluding silicon, phosphorus,
oxygen and silver) not more than 0.03 per cent.
Where silicon has been added in the manufacture of the
filler rods the amount present in the filler rod shall
be stated by the supplier.
Test pieces cut from the filler rod after being heated
in Hydrogen for ½ hour at 800°C and subsequently
cooled must not show any surface cracking when subjected
to a close bend test as described in clause (ii) above. |
| (iv) Mechanical Test |
The welding technique shall
be tested as follows:-
Three test pieces shall be cut from the welded test specimen
and shall be prepared to conform to the dimensions of
test piece A. The weld shall be left in the unhammered
state and shall be made transverse to the test Plate.
The test piece shall be machined, filled or ground to
remove excess weld metal and a maximum of 5 per cent of
the thickness of the plate from each side.
Each of the three test pieces shall be tested and shall
show a tensile strength not less than 9 tons per sq. inch
for plates upto and including ½ inch in thickness
and not less than 8 tons per sq. inch for plates over
½ inch upto and including 1 inch in thickness. |
| (v) Number of Tests |
One test plate not less than
6 inches long shall be welded by each operator (or pair
of operators) employed on the work to represent each 15
ft. of welding or part thereof. The test plate shall be
welded, using the same form of joint and welding technique
as that employed on the work and wherever practicable
shall be directly attached to the welded seam or other
welded joint it represents. |
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