How To Weld Cast Iron

Table of contents:

How To Weld Cast Iron
How To Weld Cast Iron

Video: How To Weld Cast Iron

Video: How To Weld Cast Iron
Video: How to Weld Cast Iron NO Pre-Heating | TIG Time 2024, March
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Welding the vast majority of steels in a domestic environment is not difficult with the appropriate equipment and skills. It is now quite possible to select the required welding electrodes. But if you have to weld cast iron, which, along with steel, is one of the main structural materials, then certain difficulties may arise.

How to weld cast iron
How to weld cast iron

Necessary

Copper wire, iron powder or small steel filings, solvent, liquid glue, welding electrode, chisel, chisel, drill bit, sandpaper

Instructions

Step 1

Cast iron is an iron-carbon alloy with a high carbon content. The high percentage of carbon in such an alloy leads to the fact that the carbon in the cast iron is in a free state. Thus, in gray cast iron, the most common of its other varieties, carbon exists in the form of graphite inclusions. This leads to its low ductility and fragility; it does not tolerate welding well.

Step 2

It is believed that the weldability of cast iron is related to the structure of the structure of the cast iron at the fracture site. Cast irons with a fine-grained light gray fracture are easier to weld than cast irons with a dark gray fracture and a coarse grain. Cast irons exposed to aggressive media and oiled cast irons are not weldable.

Step 3

The poor quality of the welded joint when welding cast iron is associated with intense hardening of the metal in the weld zone. In fact, we are talking about an increase in the brittleness of the metal in the specified zone. This is the main problem when welding cast iron.

Step 4

In industrial conditions, electric arc welding of cast iron is carried out by the hot method. In this case, intensive preliminary heating of the parts to be welded is performed. There is also the so-called cold method, when the parts to be welded are preheated not much or not at all. In the absence of special heating equipment, cold welding of cast iron with special electrodes seems to be more suitable.

Step 5

For the manufacture of electrodes that allow welding cast iron, take pieces of copper wire with a diameter of 3-5 mm and a length of about 450 mm, clean them with sandpaper and degrease with an organic solvent. The coating is chipped off the steel welding electrodes, crushed and mixed with iron powder in equal proportions. Fine steel filings are also fine. All this is mixed with liquid glass. The previously prepared pieces of copper wire are vertically dipped into the resulting mass and slowly removed from the creamy mass. The excess must drain off. The electrodes are dried and calcined (for example, in an oven).

Step 6

With the help of such electrodes, welding is carried out with a short arc. It is imperative to take breaks from work to cool the part. For the quality of welding, the seam should be applied in short sections up to 50 mm long and forged after welding (this is done to prevent the appearance of cracks in the welded seam).

Step 7

It should be borne in mind that before starting welding, it is always necessary to prepare the edges of the parts to be joined and cut defects in the welding places. Defective areas are cut with a chisel or drill to a pure metal.

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