What is slag inclusion in casting?
Slag Inclusion: This defect is caused when the molten metal containing slag particles is poured in the mould cavity and it gets solidifies.
Is slag an inclusion surface defect?
As, in most cases, this defect is related to furnace or melt treatment slag it can occur in all casting materials, independent of the molding or casting process. This defect is often observed on casting surfaces on top in the mold, cores, and protruding mold sections.
How can slag inclusion be prevented in casting?
Slag inclusion is caused when molten metal containing slag particles is poured into the mold cavities and solidifies. Preventing slag inclusion is a simple fix. Remove slag particles from the molten metal before pouring it into the mold cavity.
Which of the following defects occur due to slag inclusion in casting process?
Internal cavities: Blow-holes, gas porosity, pinholes, shrinkage cavity, hot tears, internal cracks, etc.
What is an inclusion defect?
Inclusion defects of castings are defects such as slag of oxides and other substances generated in the ladle by the reaction and sand of molds and the cores that flake away and are included in molten metal, flowing into products and ap- pearing on the surfaces of parts as non-metallic inclusions.
What is dross in casting?
Dross is a type of slag inclusions that forms in ductile cast iron as a result of, mainly, Mg reacting with O [1]. Global Castings has several theories as to why dross defects occur in their products; for example high O levels, a high melt temperature, turbulence and/or the chemical composition of the melt.
What causes slag inclusions?
Slag inclusions are nonmetallic particles trapped in the weld-metal or at the weld interface. Slag inclusions result from faulty welding technique, improper access to the joint, or both. Sharp notches in joint boundaries or between weld passes promote slag entrapment.
What are inclusions defects?
Why does slag inclusion occur?
What are the common defects of casting?
They are broken down into five main categories: gas porosity, shrinkage defects, mould material defects, pouring metal defects, and metallurgical defects.
How would you prevent slag inclusion and undercut?
The following techniques can be used to prevent slag inclusions: Use welding techniques to produce smooth weld beads and adequate inter-run fusion to avoid forming pockets to trap the slag. Use the correct current and travel speed to avoid undercutting the sidewall which will make the slag difficult to remove.
Is dross and slag the same?
Dross is a residue that is left on the surface of molten metal, while slag is the material that separates from molten metal.
How do I remove dross?
How can dross be removed? Manually, this dross can be scraped off the metal with a hammer or knife. This intensive work is time-consuming and there is a risk of injury for the worker. After the slag is removed, a sanding machine is needed to make the surface smooth and to leave a nice finish.
How do you remove slag from steel?
How To Easily Remove Slag – YouTube
What causes inclusions in casting?
Inclusions can be caused by various factors, including impurities from the metal ingot or interaction of the metal with the mould surfaces or the outside atmosphere. Inclusions are problematic because they can affect the mechanical properties of the metal casting. They are usually identified through x-ray detection.
What is the purpose of slag?
Slag’s purpose is two-fold. It protects the weld from oxidation and contamination from the atmosphere. It also helps keep the molten weld pool in the joint as it cools, which is especially important for out-of-position welding.
What causes porosity?
Porosity is caused by the absorption of nitrogen, oxygen and hydrogen in the molten weld pool which is then released on solidification to become trapped in the weld metal. Nitrogen and oxygen absorption in the weld pool usually originates from poor gas shielding.
What is cold shut defect?
A cold shut occurs when the molten material has begun to solidify before fully filling the mould. When the molten metal begins solidifying before the mould has been completely filled, it can form a seam that hasn’t merged correctly. This results in severe weak spots in the casting.
What is the main causes of slag inclusion?
What are the causes of undercut?
Causes of Undercutting
- High Speeds of Electrode Movement.
- Excessive Heat Generated.
- Poor Welding Technique.
- Greater Arc Length.
- Wrong Electrode Size.
- Holding the Electrode at a Wrong Angle.
- Contaminated Shielding Gas.
- Incorrect Proportion of the Filler Material.
How is dross removed?
First, heat the ore to remove the sulfur, being careful not to inhale the toxic fumes of sulfuric acid. Second, oxidize (i.e. burn) the remainder in shallow pans so that the lead will form lead oxide, the dross. Third, collect the pure silver now separated out on the bottom of the pans.
What is the difference between dross and slag?
How is slag removed?
The slag removal process is carried out by dispersing natural granular perlite on top of the molten metal. The coagulating, encapsulating effect of the perlite allows slag to be easily removed from ladles and furnaces.
What tools can be used to remove slag?
Chipping hammers and similar tools are often used to remove slag, and while they’re effective, they’re also the slowest option. Angle grinders can also remove slag, which are much faster than using a handheld chipping hammer.