Annealing - Revision history

Designing Buildings at 07:04, 25 February 2021

2021-02-25T07:04:42Z

← Older revision		Revision as of 07:04, 25 February 2021
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	* Window.		* Window.

−	[[Category:~~Products_/_components~~]] [[Category:DCN_Product_Knowledge]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Products_/_components]]

Designing Buildings at 11:11, 27 January 2020

2020-01-27T11:11:42Z

← Older revision		Revision as of 11:11, 27 January 2020
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	= Introduction =		= Introduction =

−	Annealing is a much-used process of heat treatment which involves heating a material for a given time ~~at an elevated temperature~~ then allowing it to cool in a slow, controlled manner. The aim is to increase ductility, strength and remove internal stresses. It is usually applied to glass and metals.	+	Annealing is a much-used process of heat treatment which involves heating a material for a given time then allowing it to cool in a slow, controlled manner. The aim is to increase ductility and strength and to remove internal stresses. It is usually applied to glass and metals.

	= Glass =		= Glass =
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	The annealing of float glass immediately after it has been formed helps dissipate any internal stresses which may have been induced during the manufacturing process. The result is a glass that is harder to break than ordinary glass.		The annealing of float glass immediately after it has been formed helps dissipate any internal stresses which may have been induced during the manufacturing process. The result is a glass that is harder to break than ordinary glass.

−	Manufacturing smaller glass objects may involve annealing as an incidental process – i.e cooling takes place in time during manufacture without a specific annealing process. But with larger or more complex objects, such as long ribbons of float glass, a specific annealing process ~~will have to~~ be introduced using a temperature-controlled kiln called a lehr. There can be safety concerns using annealed glass as it can break into large, jagged shards.	+	Manufacturing smaller glass objects may involve annealing as an incidental process – i.e cooling takes place over time during manufacture without a specific annealing process. But with larger or more complex objects, such as long ribbons of float glass, a specific annealing process can be introduced using a temperature-controlled kiln called a lehr. NB There can be safety concerns using annealed glass as it can break into large, jagged shards.

−	A typical annealing process may form part of the manufacture of float glass: after the glass has been poured onto the molten tin in ribbons at an initial temperature of around 1,200°C, it travels under gravity or by top roller gears propelling it forward. Having cooled slightly to around 1,100°C, the glass enters a lehr oven to be annealed i.e allowed to cool very gradually over a specific time period until it reaches the required temperature.	+	A typical annealing process that may form part of the manufacture of float glass

−	The time required to anneal glass will depend on the glass type and the thickness. When it finally emerges from the oven, the glass may be further cooled by jets of air after which scanners seek any imperfections which, if found, will result in the glass being discarded or recycled.	+	* After the glass has been poured onto the molten tin in ribbons at an initial temperature of around 1,200°C, it travels under gravity or by top roller gears propelling it forward.
		+	* Having cooled slightly to around 1,100°C, the glass enters a lehr oven to be annealed i.e allowed to cool very gradually over a specific time period until it reaches the required temperature. The time required to anneal glass will depend on the glass type and the thickness.
		+	* When it finally emerges from the oven, the glass may be further cooled by jets of air after which scanners seek any imperfections which, if found, will result in the glass being discarded or recycled.

−	If glass is not properly annealed, it ~~retains~~ thermal stresses which can ~~drastically~~ decrease its strength and make for a less reliable product; it may therefore crack or shatter even under small temperature changes, mechanical shock or stress. It can even suffer sudden failure.	+	If glass is not properly annealed, it may retain thermal stresses which can significantly decrease its strength and make for a less reliable product; it may therefore crack or shatter even under small temperature changes, mechanical shock or stress. It can even suffer sudden failure.

	= Metal =		= Metal =
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	The annealing of metals – such as alloys, stainless steel, copper, silver and brass – also involves a heat treatment process that alters their physical characteristics, reducing hardness and increasing ductility and malleability. Therefore, metals can be softened in preparation for further processing such as forming, shaping and stamping.		The annealing of metals – such as alloys, stainless steel, copper, silver and brass – also involves a heat treatment process that alters their physical characteristics, reducing hardness and increasing ductility and malleability. Therefore, metals can be softened in preparation for further processing such as forming, shaping and stamping.

−	The annealing process for metals is essentially similar to that for glass: the metal is heated to above the temperature required for recrystallisation – in the case of steel, copper, silver and brass this will be until they glow~~; the~~ temperature is maintained for the required time and then cooled in a slow, controlled process, possibly down to room temperature. As the metal cools, recrystallisation takes place within the matrix until the required temperature is reached. However, further heat treatments may be needed, depending on the degree of malleability and hardness required.	+	The annealing process for metals is essentially similar to that for glass: the metal is heated to above the temperature required for recrystallisation – in the case of steel, copper, silver and brass this will be until they glow. The temperature is maintained for the required time and then cooled in a slow, controlled process, possibly down to room temperature. As the metal cools, recrystallisation takes place within the matrix until the required temperature is reached. However, further heat treatments may be needed, depending on the degree of malleability and hardness required.

	Steel requires slow cooing in air to anneal, but copper, silver and brass can also be cooled by quenching (quench annealing) whereby they are cooled quickly by immersion in water.		Steel requires slow cooing in air to anneal, but copper, silver and brass can also be cooled by quenching (quench annealing) whereby they are cooled quickly by immersion in water.
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	* Overheating.		* Overheating.
	* Patent glazing.		* Patent glazing.
−	* Preventing overheating.
−	* R-value.
−	* Rights to light.
	* Safety glass.		* Safety glass.
	* Secondary glazing.		* Secondary glazing.
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	* Window.		* Window.

−	[[Category:Products_/_components]]	+	[[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

Editor at 19:33, 24 January 2020

2020-01-24T19:33:35Z

← Older revision		Revision as of 19:33, 24 January 2020
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	* R-value.		* R-value.
	* Rights to light.		* Rights to light.
		+	* Safety glass.
	* Secondary glazing.		* Secondary glazing.
	* Security glazing.		* Security glazing.

Editor: Created page with "= Introduction = Annealing is a much-used process of heat treatment which involves heating a material for a given time at an elevated temperature then allowing it to cool in a s..."

2020-01-24T17:46:39Z

Created page with "= Introduction = Annealing is a much-used process of heat treatment which involves heating a material for a given time at an elevated temperature then allowing it to cool in a s..."

New page

= Introduction =

Annealing is a much-used process of heat treatment which involves heating a material for a given time at an elevated temperature then allowing it to cool in a slow, controlled manner. The aim is to increase ductility, strength and remove internal stresses. It is usually applied to glass and metals.

= Glass =

The annealing of float glass immediately after it has been formed helps dissipate any internal stresses which may have been induced during the manufacturing process. The result is a glass that is harder to break than ordinary glass.

Manufacturing smaller glass objects may involve annealing as an incidental process – i.e cooling takes place in time during manufacture without a specific annealing process. But with larger or more complex objects, such as long ribbons of float glass, a specific annealing process will have to be introduced using a temperature-controlled kiln called a lehr. There can be safety concerns using annealed glass as it can break into large, jagged shards.

A typical annealing process may form part of the manufacture of float glass: after the glass has been poured onto the molten tin in ribbons at an initial temperature of around 1,200°C, it travels under gravity or by top roller gears propelling it forward. Having cooled slightly to around 1,100°C, the glass enters a lehr oven to be annealed i.e allowed to cool very gradually over a specific time period until it reaches the required temperature.

The time required to anneal glass will depend on the glass type and the thickness. When it finally emerges from the oven, the glass may be further cooled by jets of air after which scanners seek any imperfections which, if found, will result in the glass being discarded or recycled.

If glass is not properly annealed, it retains thermal stresses which can drastically decrease its strength and make for a less reliable product; it may therefore crack or shatter even under small temperature changes, mechanical shock or stress. It can even suffer sudden failure.

= Metal =

The annealing of metals – such as alloys, stainless steel, copper, silver and brass – also involves a heat treatment process that alters their physical characteristics, reducing hardness and increasing ductility and malleability. Therefore, metals can be softened in preparation for further processing such as forming, shaping and stamping.

The annealing process for metals is essentially similar to that for glass: the metal is heated to above the temperature required for recrystallisation – in the case of steel, copper, silver and brass this will be until they glow; the temperature is maintained for the required time and then cooled in a slow, controlled process, possibly down to room temperature. As the metal cools, recrystallisation takes place within the matrix until the required temperature is reached. However, further heat treatments may be needed, depending on the degree of malleability and hardness required.

Steel requires slow cooing in air to anneal, but copper, silver and brass can also be cooled by quenching (quench annealing) whereby they are cooled quickly by immersion in water.

= Related articles on Designing Buildings Wiki =

* BREEAM Visual comfort View out.
* Curved glass.
* Daylit space.
* Domestic windows.
* Double glazing.
* Emissivity.
* Glass.
* Low-E glass.
* Overheating.
* Patent glazing.
* Preventing overheating.
* R-value.
* Rights to light.
* Secondary glazing.
* Security glazing.
* Structural glass assembly.
* Suction lifter.
* Types and manufacture of laminated glass.
* Types of window.
* U-value.
* Window.

[[Category:Products_/_components]]