Page 134 - CITS - Welder - Trade Practical

WELDER - CITS

Skill Sequence

Square butt joint on stainless steel sheet 3mm thick in flat

position

Objectives: At the end of this exercise you shall be able to
• prepare and weld square butt joint on stainless steel sheet 3mm thick in flat position.

Prepare the stainless-steel sheet as per dimensions given in the sketch.
Use a stainless-steel wire brush to clean the edges of the sheets and remove any chromium oxide and other
impurities from the edges.
Select nozzle No. 5 and fix on the blowpipe.
Select a 1.6 mm ø specially treated columbium bearing 18/8 type stainless steel filler rod, or cut strips from the
base metal to use as filler rod. 18/8 stainless steel means the alloy steel contains 18% chromium, 8% nickel and
the balance % is iron, carbon % etc.
Select good quality flux which contains zinc chloride and potassium dichromate; make powdered flux in a pasty
form by adding water. Apply the flux on both sides of the plate and filler rod.
Set the sheets as butt joint on a thick metal plate with 1.5 mm gap as shown in Fig 1.
Set a strict neutral flame or slightly carburizing flame so as to prevent the formation of oxidizing flame which is
harmful.
Tack-weld on both ends of the joints and for every 50 mm in between them.
Start welding from the right-hand side by holding the blowpipe at an angle of 80° to 90° and the filler rod at 20°
to 30°. (Fig 2)
Note : Ensure uniform penetration at the root of the joint.
Finish the weld by filling up the crater at the end of the bead.
Clean the weld bead and inspect.

Note : Ensure the complete removal of the flux residues.

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CITS : C G & M - Welder - Exercise 27