Difference Between Coated Glass And Heat Strengthened Glass. In this article, you will come to know about what is coated glass, what is heat strengthened glass, what is the main difference between coated glass and heat strengthened glass, and much more.
Both the terms coated glass and heat strengthened glass are the types of glasses that are used in construction and for different purposes. Glass is a transparent substance that can be transparent, translucent, or brittle. The process that is used to manufacture the glass is known as the ‘fusion process’. In this process, the sand is fused with soda, lime, and various admixtures. Then this mixture is cooled rapidly, thus forming a glass.
The difference in the glasses lay in their making process. Here, we will first discuss the main difference between coated glass and heat strengthened glass, then differentiate between them in detail.
What Is The Main Difference Between Coated Glass And Heat Strengthened Glass?
The main difference between coated glass and heat strengthened glass is that the:
-Coated Glass is produced by applying the coating to the finished glass through a process called sputter coating. Various metal oxides are sprayed in the form of thin coatings from 0.01 µm to 0.8 µm.
-Heat Strengthened Glass is made by the same process used in making tempered glass, but the cooling process is slower. This results in a lower surface compression of 3,500 to 7,500 psi, which makes it stronger than annealed glass.
What Is Coated Glass?
Coated Glass is produced by applying the coating to the finished glass through a process called sputter coating. Various metal oxides are sprayed in the form of thin coatings from 0.01 µm to 0.8 µm. The coatings are applied by the controlled exposure of the glass to vapours.
Special coatings modify the appearance of the glass and enhance its characteristics. Like special reflection/transmission/absorption properties, scratch resistance, corrosion resistance, low maintenance, etc.

There are two types of coated glass, i.e. Hard-coat glass and Soft-coat glass.
-Hard coat is made by pouring a thin layer of metallic oxide onto a sheet of glass while the glass is still on the float line, just after it has been formed into a thickness ribbon. The metallic oxide layer actually becomes welded to the glass surface. This process makes it very difficult or hard to scratch or remove the coating therefore why it is referred to as a hard coat. Often this glass has a bluish tint to it. Low E and Self Cleaning coatings fall under this category.
-Soft Coat involves the application of silver, zinc or tin (or a combination of) to glass that has already been formed and taken off the float line. The coating is softer than online coated glass therefore why it is referred to as a soft coat. Furthermore, if silver is used (and it often is) the offline coating can oxidise if exposed to normal air. For this reason, offline coated glass must be used in an insulated glass unit (IGU).
What Is Heat Strengthened Glass?
Heat Strengthened Glass is made by the same process used in making tempered glass, but the cooling process is slower. This results in a lower surface compression of 3,500 to 7,500 psi for 6mm glass, which makes it stronger than annealed glass. It has more resistance to thermal loads and is stronger as compared to annealed glass.

This glass is also referred to as semi-tempered. That’s why it cannot be used as a safety glass. It cannot be cut, drilled, edge-ground, or sandblasted after the heat strengthening. Heat-strengthened glass is shattered like tempered glass, however, it got fractured into dangerous large shards.
What Are The Properties Of Glass?
The 6 main properties of glass are as under:
1.Transparency:
The main property of glass is transparency. The more transparent the glass, the better the vision of that glass. Usually, the glasses are transparent from both sides, but there is some glass that is transparent from one side only. An example of such types of glasses are mirrors that have only one side transparency.
2.Strength:
The strength of glass is the second property of glass. It depends on the modulus of the ruptured value of glass. The glass is very brittle initially. We add admixtures and laminates to make it stronger.
3.Workability:
The workability of the glass is a superior property. Glass can be moulded into any shape when melted.
4.Transmittance:
A glass should have visible transmittance property. It means that a visible fraction of light should pass through the glass.
5.U-value:
The u-value of the glass is the amount of heat that can be passed through the glass. Like, if the glass is insulated the glass will have a lower u-value.
6.Recyclable:
A glass can always be recycled. It has 100% recyclable property. It is used as a raw material in the construction industry.
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