foundries of CI castings

1. Foundries of CI Castings
PRESNTED BY - MD SHAMSHER HOSSAIN.
M.E:- 3RD YEAR

2. Foundries of CI Castings
 Inroduction
 How Foundries Perform Welding Of Cast Iron Castings?
 Images of Cast Iron Castings
 Welding Techniques With Preheat
 Welding Techniques Without Preheat
 Conslusion

3. Introduction
 Engineers may find the job of welding bit tricky, yet they do it all
with perfection under harsh environment. In most cases, welding
process of cast iron involves casting repairs. These repairs may be
done inside the foundry that is producing various cast iron castings,
or may be done when engineers determine them after machining
process. Defected cast iron components can be repaired with
welding technique. Broken cast iron components are rare and fixed
by welding process.

4. How Foundries Perform Welding Of Cast Iron Castings?
 Manufacturers of castings use various range of cast iron and out of them, gray iron is their
most preferred material to cast and shape. We are now going to discuss about a fact file of
cast iron that helps us in understanding the challenges of welding.
(1) Cast iron usually has 2%-4% carbon content (this is about 10 times more than steel).
(2) Due to presence of more carbon content, it form graphite flakes.
(3) This graphite offers gray cast iron its characteristics looks when fractured.
(4) When manufacturers form castings, molten cast iron is poured inside a mold cavity and
allowed to set and slowly cool down.
(5) With such slowly cooling technique, foundries can achieve crack-free or defect-less
castings. It is necessary to keep the casting at cool place during or after welding process.

5. Images of Cast Iron Castings

6. Welding Techniques With Pre-heat
 Performing preheating process for cast iron parts prior welding will
slow down the cooling rate of the weld and its surrounded region. As
per experts, one should heat the entire casting and preheat temperature
should be range from 500° F to 1200° F. Overheating will make the
temperature critical for casting part. It is important to preheat the part
uniformly and slowly to reduce cracking tendencies.

7. Welding Techniques Without Pre-heat
 The size and other circumstances influence engineers to repair
castings with welding by eliminating preheat process. For this, they
keep the part cool, but not cold. The casting temperature raised to
100°F and if the part is located on an engine, engineers me run it
for a few minutes to attain this range of temperature. Heat the
casting up to the temperature at which you can place your hand on
it.
 After welding, peening is necessary and you should not raise the
cooling rate with compressed air or water.

8. Conclusion
 This is how cast iron castings foundries perform welding process.
After Peening, they seal the cracks and give the perfect finish to
the component.

9. THANK YOU
MD.SHAMSHER HOSSAIN
M.E: 3RD YEAR