Heat Treatment of Aluminum and Aluminum Alloys

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The non-heat-treatable alloys depend primarily on cold work to increase strength.

Annealing

Annealing is applied to both grades to promote softening. Complete and partial annealing heat treatments are the only ones used for non-heat-treatable alloys. The exception is the 5000 series alloys which are sometimes given low-temperature stabilization treatment and this is carried out by the producer.

Annealing is carried out in the range 300-410°C depending on the alloy. Heating times at temperature vary from 0.5 to 3 hours, conditional on the size of the load and the alloy type. Generally, the time need not be longer than that required to stabilize the load at temperature. Rate of cooling after annealing is not critical.

Where parts have been solution heat-treated a maximum cooling rate of 20°C per hour must be maintained until the temperature is reduced to 290°C. Below this temperature, the rate of cooling is not important.

Solution Heat Treatment

This is applicable to the heat-treatable alloys and involves a heat treatment process whereby the alloying constituents are taken into solution and retained by rapid quenching. Subsequent heat treatment at tower temperatures i.e. aging or natural aging at room temperature allows for controlled precipitation of the constituents thereby achieving increased hardness and strength.

Time at temperature for solution treatment depends on the type of alloy and the furnace load. Sufficient time must be allowed to take the alloys into solution if optimum properties are to be obtained.

The solution treatment temperature is critical to the success of the procedure. It is desirable that the solution heat treatment is carried out as close as possible to the liquidus temperature in order to obtain the maximum solution of the constituents. Accurate furnace temperature and special temperature variation must be controlled to within a range of ±5°C for most alloys. Overheating must be avoided i.e. exceeding initial eutectic melting temperatures. Often the early stages of overheating are not apparent but will result in a deterioration of mechanical properties.

Proper solution heat treatment of the aluminum alloys requires expert knowledge of the alloy being treated plus the correct heat treatment plant.

Quenching

This is a critical operation and must be carried out to precise limits if optimum results are to be obtained. The objective of the quench is to ensure that the dissolved constituents remain in solution down to room temperature.

The speed of quenching is important and the result can be affected by excessive delay in transferring the work to the quench. The latitude for the delay is dependent on the section and varies from 5 to 15 seconds for items of thickness varying from 0.4mm to 12.7mm. Generally, very rapid precipitation of constituents commences at around 450°C for most alloys and the work must not be allowed to fall below this temperature prior to quenching.

Another factor to be considered in quenching is the work load and the ability of the quenchant to extract the heat at sufficient rate to achieve the desired results.

The usual quenching medium is water at room temperature. In some circumstances, slow quenching is desirable as this improves the resistance to stress corrosion cracking of certain copper-free Al-Zn-Mg alloys.

Parts of complex shapes such as forgings, castings, impact extrusions and components produced from sheet metal may be quenched at slower quenching rates to improve distortion characteristics.

Thus a compromise must be considered to achieve a balance of properties in some instances. Quenchants used in slower quenching applications include water heated to 65-80°C, boiling water, aqueous solutions of polyalkalene glycol or forced air blast.

Age Hardening

After solution treatment and quenching, hardening is achieved either at room temperature (natural aging) or with a precipitation heat treatment (artificial aging). In some alloys, sufficient precipitation occurs in a few days at room temperature to yield stable products with properties that are adequate for many applications. These alloys sometimes are precipitation heat treated to provide increased strength and hardness in wrought and cast alloys. Other alloys with slow precipitation reactions at room temperature are always precipitation heat treated before being used.

In some alloys, notably those of the 2xxx series, cold working of freshly quenched materials greatly increases its response to later precipitation treatment. Mills take advantage of this phenomenon by applying a controlled amount of rolling (sheet and plate) or stretching (extrusion, bar and plate) to produce higher mechanical properties. However, if the higher properties are used in the design, reheat treatment must be avoided.

Where natural aging is carried out the time may vary from around 5 days for the 2xxx series alloys to around 30 days for other alloys. The 6xxx and 7xxx series alloys are considerably less stable at room temperature and continue to exhibit changes in mechanical properties for many years. With some alloys, natural aging may be suppressed or delayed for several days by refrigeration at -18°C or lower. It is common practice to complete forming, straightening and coining before aging changes material properties appreciably. Conventional practice allows for the refrigeration of alloys 2014 - T4 rivets to maintain good driving characteristics.

The artificial aging or precipitation heat treatments are low-temperature long-time processes. Temperatures range from 115-200°C and times from 5-48 hours. As with solution treatment, accurate temperature control and spatial variation temperatures are critical to the process and generally, temperatures should be held to a range of ±7°C.

The change of time-temperature parameters for precipitation treatment should receive careful consideration. Larger particles or precipitates result from longer times and higher temperatures. The objective is to select the cycle that produces the optimum precipitate size and distribution pattern. Unfortunately, the cycle required to maximize one property, such as tensile strength, is usually different from that required to maximize others such as yield strength and corrosion resistance. Consequently, the cycles used represent compromises that provide the best combination of properties.

Wellste: Your Top Aluminium Profiles for Windows and Doors Manufacturer

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Aluminum Profiles for Windows and Doors: The Complete FAQs Guide

Aluminum profiles for windows and doors refer to aluminum products featuring different section shapes often produced through extrusion process.

They are used for structural purposes in different construction, architectural and industrial settings.

This FAQs guide presents in-depth information regarding various aspects of these aluminum products.

It allows you to understand numerous elements to facilitate your decision-making process when shopping for the most suitable pieces.

Aluminum Profile for Windows and Doors

How Do You Manufacture Aluminum Profiles For Windows and Doors?

Notably, extrusion is the primary technique used for making these designs of aluminum profiles.

It is quite a detailed process, which starts with designing every profile.

The designing process involves documenting specific functions of the profiles, shapes, dimensions, and material specifications.

Machinability, finishing, and durability are also other crucial aspects considered during design process.

After completing the designing process using computer software, steel die for producing the design is also produced.

It involves using a hydraulic press to push the billet through the die to create the desired window or door aluminum profile.

The actual extrusion process involves the following details;

Extrusion Billets

A typical extrusion billet comes in form of a solid or hollow cylindrical shape.

In most instances, the billets are cast in an electric arc furnace with aluminum scraps. They are cut into ideal sizes to match the required profile length.

Preheating Billet

Preheating of the billet and extrusion die takes place before the actual extrusion process starts. The essence is to soften the billet to allow it to be forced through the die?

While at it, you should be careful not to overheat it to a melting point, often about 1200° F. An ideal heating point should be approximately 900° F.

Direct Extrusion

This stage entails actual extrusion process, which begins immediately after the ram starts exerting pressure on the billet. Extrusion machine features a hydraulic press, which can exert pressure of up to 15,000 tons on the billet and die.

Ideally, the more the pressure, the greater the extrusion it can produce. The machine applies the initial pressure crushing the billet against the die.

This die becomes shorter and wider until it can never expand anymore due to container wall restriction. That’s when the aluminum material starts forcing its way out through the die’s orifice and form a particular profile.

Length of an extruded profile is dependent on billet and die opening sizes. There is a runout conveyor, which supports the formed extrusion profile as it comes out of the extrusion press.

Extruded profile may be passed into a cooling bath as it comes out depending on the type of alloy. Cooling is a critical step since it retains adequate metallurgical properties in the metal.

After cooling, you can use the stretcher to stretch these profiles and straighten any twisted part.

Surface Treatment

These profiles are taken through a special surface treatment module to attain the ideal surface finishing. It varies based on user preference and actual setting of the windows and doors.

Cutting

After special finishing operations, you may cut the profiles into shorter lengths depending on the actual dimensions of the windows and doors. While at it, you may use special devices to clamp the profiles, cut and transfer them to a conveyor.

Aging

This process helps to strengthen the aluminum profiles for windows and doors. You can attain natural aging by exposing the profiles to room temperature.

Alternatively, you can go for artificial aging in an oven. Essentially, the aging process design is to ensure there is uniform precipitation of fine particles through the metal.

It allows the metal to obtain full strength, elasticity, and hardness.

How Can You Connect Aluminum Profiles For Windows And Doors?

There are several techniques you can use to connect windows and doors aluminum profiles. However, the most suitable one is dependent on the actual framing design of the specific window or door.

Some of the commonly used ways include the following;

Screw Port

It is quite popular and can be used with self-tapping screws or merely threaded to take a machine screw.

This mode of connection offers a strong and robust fix and allowing easy disassembly. You should always consider giving clearance for screw head.

Snap-fit

This is regarded as the easiest and fastest way to fix different aluminum profiles.

You can use it as a decorative feature for hiding unsightly screw heads on the surface material.

It hardly requires foreign fixing, which facilitates recycling. Snap-fit technique features lead-in barbs allowing the top extrusion to slide and clip over the bottom one.

Since aluminum has a natural flex, it provides a positive snap. However, you should take note that a barb without reverse chamfer may form a permanent snap-fit.

Snap Fitting of Aluminum Windows and Door Profile

Interlocking

Relatively simple and effective method for connecting aluminum profiles for windows and doors. It allows two profiles to attain a strong and quick fix.

You can attain this by sliding one feature over the other.

Notably, window and door aluminum profiles often have both male and female features in same profile.

It thus implies that you can use same extrusion for top and bottom.

However, this technique requires sliding its entire length. As such, it may be unsuitable to use in somewhat confined spaces.

Normally, it is a perfect choice for sliding window aluminum frame.

Corner Cleat

It is the ideal method for connecting two identical extrusion profiles at a particular angle. The profile has a channel allowing the cleat often made of another aluminum profile or sheet steel.

This cleat may have a few barbs on each side, cutting into the aluminum to create a friction fit. Alternatively, you can add screws to fix the cleat in position.

Nut Track

This method features a channel designed to fit a nut or bolt head firmly between the flats.

The essence is to prevent nut or bolt head from spinning. You can use multiple fasteners in a single track and position freely.

Hinge

It is the ideal method to fix aluminum profiles while allowing movement. You can attain this in many ways by using two cylindrical features.

Why Is Aluminum Best For Windows And Door Profiles?

Aluminum windows and doors are presently used in a wide range of commercial, industrial, and residential structural products.

Essentially, these components have enhanced efficiency, durability, and performance in various applications.

They also provide better aesthetics and longevity compared to traditionally used materials like PVC.

Here are other vital reasons, which make aluminum material the most suitable for making windows and door profiles;

Optimum Safety

Aluminum offers exceptional strength making it difficult for intruders and unauthorized people to break in.

The framing holds high-quality hardware and multipoint locking systems offering good security for the windows and doors.

Incredible Strength To Weight Ratio

Aluminum is ideal for contemporary windows and doors framing since the material is strong and bears a substantially large amount of weight.

Its low density enables you to have slim profiles sturdy enough to hold the glass weight.

Superior strength of aluminum material allows you to create unique shapes and designs. These profiles may also hold multiple glass panes without compromising operation.

Excellent Durability And Low Maintenance

Aluminum windows and doors profiles are easy to maintain.

You only require a mild detergent and washcloth to clean and restore the surface material to its original appearance and lustre.

Additionally, powder coated aluminum profiles for windows and doors can withstand corrosion and other harsh environmental conditions.

Thus, you can use it in any environment and still attain desirable results.

Offers A Wide Range Of Shapes And Designs

You can easily choose the specific design or shape of aluminum profile suitable for your windows and doors.

Moreover, they also come in various colors, thus increasing your choice options based on your taste and preference.

Exhibits Ideal Energy Efficiency

Aluminum features thermal breaks or strips, which can stop heat gain or loss coming from the windows and doors.

What Are The Mechanical Properties Of Aluminum Profiles For Windows and Doors?

Technically, making aluminum profiles for windows and doors involves altering most of its physical characteristics. However, definitive cross-sections are introduced in the profile to boost its versatility.

Here are some of the mechanical features of aluminum profiles for windows and doors;

Lightweight

Extruded aluminum is about 1/3 less than iron or brass, a clear indication it is comparatively a lightweight material.

Moreover, the lightweight nature of this material hardly compromises its strength. As such, it becomes suitable for making different designs of windows and doors profiles for usage in various settings.

Recyclable

Ideally, any recyclable material is fundamental. It means you can use the substance many times, which reduces production costs significantly.

Aluminum is recyclable irrespective of the number of years the piece has served.

Sturdy

Typical aluminum material for windows and doors profiles is often taken through aging process during extrusion. The process strengthens the material, and as temperature reduces, its strength increases.

Thus, this material can withstand high pressure without running its form or dimensions, making it ideal for windows and doors profiles.

Flexible

You can easily tune aluminum material to form different preferred shapes. Ideally, the extrusion process allows aluminum for making windows and doors relatively flexible.

Moreover, the material features definitive cross-sections allowing an easier machining process, which increases flexibility.

Non-corrosive

Extruded aluminum material is immune to corrosion thus can withstand harsh environmental conditions. Of course, this is advantageous since it means the resultant windows and doors profiles can last several years without deformation.

Non-combustible And Non-sparking

This material can tolerate high temperatures without burning or emitting toxic fumes. In essence, this property makes it eco-friendly and ideal for industrial applications.

Moreover, extruded aluminum hardly produces sparks irrespective of the friction it is subjected to.

Easy Alloying

Notably, aluminum material is compatible with various metals making it easy to form different alloys.

You can use simple formation processes such as riveting, welding, brazing, and adhesive bonding to create different aluminum alloys.

Ideally, aluminum features favorable texture making it easy to form alloys with different metals using simple means.

What Is The Life Span Of Aluminum Profiles For Windows And Doors?

Extruded Aluminum Profile for Windows and Doors

Generally, they are durable since the material is solid and exhibits high resistance to many mechanical and environmental conditions.

The type of aluminum material used for windows and doors profiles undergo extrusion process. During the process, they are taken through aging, which is a process for strengthening and enhancing the material’s elasticity.

Ideally, aging during extrusion process ensures there is even precipitation of particles on the surface material.

As such, it makes the material hardy and thus can withstand different harsh environmental and mechanical conditions.

Nonetheless, typical aluminum profiles for windows and doors can last for more than 10 years.

How Much Do Aluminum Profiles For Windows And Doors Cost?

There is no absolute cost for aluminum profiles for windows and doors. Notably, several factors influence the specific amount you pay to obtain these components, such as follows;

Design And Shape

You can always find aluminum profiles for windows and doors in various designs and shapes.

Of course, there are standard designs and shapes, but most users go for customized pieces depending on their projects. As such, the cost will vary since the latter is usually more expensive than the former.

Quantity

Most manufacturers often offer discounted rates on high quantity purchases as opposed to purchasing low volume.

Therefore, purchasing more aluminum profiles for windows and doors is seemingly more cost-effective and vice versa.

Brand

Various manufacturers price their specific aluminum profiles for windows and doors differently.

In most instances, the pricing is usually based on the company’s reputation in providing quality aluminum profiles

Ideally, relatively known manufacturers tend to be costlier than less known companies.

However, it doesn’t in anyway imply that the less known brands in the market do not produce quality aluminum profiles for windows and doors.

Material Thickness

Essentially, aluminum profiles with relatively thick materials tend to be costlier than vice versa.

Surface Finishing

You can find these types of profiles in a wide range of surface finishing.

Ideally, each type of surface finishing determines the specific cost of the profiles since they are unique and have different specifications.

In other words, the actual cost of your ideal aluminum profiles for windows and doors is dependent on numerous factors, including the aforementioned ones.

Which Material Grade Do You Use For Aluminum Profiles For Windows And Doors?

Aluminum profiles for windows and doors use a wide range of aluminum grades.

However, it is vital to understand only a few grades can provide high quality components.

The most suitable and commonly used grades for windows and doors are 6000 series, which include the following;

6061 Aluminum Grade

Arguably, one of the most popular and preferred aluminum grades for making window and door profiles. It is an alloy featuring highest level of corrosion resistance in the heat-treated aluminum alloy family.

6061 grade exhibits somewhat low strength compared to other grades in the 6000 series. Moreover, it has wide-ranging mechanical properties giving it incredible forming capabilities.