Solutionizing Process

Introduction to the Solutionizing Process

The solutionizing process is a crucial heat treatment method used across various industries. This process is designed for the material is heated and soaked at its Solvus temperature limits of solubility in its solid phase. This is done to dissolve the precipitates and reduce the segregation that might be present in the alloy which enhances the strength, toughness, wear resistance of alloy components andcorrosion resistance of materials, making them suitable for high-performance applications.

Industries like automotive, aerospace, defence, medical and construction rely on solutionizing furnaces like drop bottom quench furnaces to process materials like aluminium, titanium, and steel. This ensures a uniform microstructure, eliminating phase segregation and defects.

What is Solutionizing Heat Treatment?

In simple terms, solutionizing heat treatment is a process where metals are heated to a specific temperature to dissolve alloying elements into a single-phase structure. After maintaining this temperature for a certain duration, the metal is rapidly cooled (quenched) to prevent unwanted phase formation.

This process is especially useful in aluminium and steel alloys, where it prepares the metal for further strengthening through ageing heat treatment. The combination of these two heat treatment processes significantly enhances the durability and performance of the material.

Key Steps in the Solutionizing Process

1. Heating Phase

The first and most crucial step of the solutionizing process is heating the material to a predetermined temperature. This temperature must be carefully controlled to ensure that all alloying elements dissolve into the base metal.

• Aluminium alloys: 450°C – 570°C
• Steel alloys: 900°C – 1200°C
• Titanium alloys: 800°C – 1000°C

The heating must be slow and uniform to prevent thermal distortion in the material. Many industries use aluminium drop-bottom solutionizing furnaces to maintain precise control over the heating process.

2. Holding Phase (Soaking Time)

Once the desired temperature is reached, this allows the alloying elements to fully dissolve into the matrix. The soaking time varies based on the material thickness and composition. Holding the material for the correct duration ensures complete homogenization, eliminating weak spots in the metal structure.

3. Quenching Phase

After the holding phase, the metal is rapidly cooled to retain the homogeneous structure. The quenching medium plays a crucial role in determining the final properties of the metal.

• Water quenching: Used for high-strength aluminium alloys.
• Oil quenching: Common for steels requiring moderate cooling rates.
• Air quenching: Preferred for certain titanium and low-carbon steel alloys.

Rapid cooling freezes the uniform phase, preventing segregation or precipitation of unwanted compounds.

Types of Solutionizing Furnaces

To carry out effective heat treatment, industries use specialized solutionizing furnaces. These furnaces provide controlled heating, soaking, and timed quenching for various metals.

1. Aluminium Drop Bottom Solutionizing Furnace

A drop bottom quench furnace is widely used for aluminium solutionizing.These furnaces are designed with rapid quenching by advanced design movement, placing the quenching tank under the furnace, Once the charge is heated it is dropped to be quenched immediately.

Temperature Range: 500°C to 600°C

Standard Applications: Solution Annealing/Solutionizing for T6 Process Chamber Design: Cylindrical/Rectangular

Temperature Uniformity: +/-5 °C or Class 2 (+/-6 °C)

Additional Features: Automated Operation with Quench Delay of 5 seconds to 15 Seconds with PLC and SCADA for data acquisition.

These Drop bottom Furnaces for aluminium can also be designed and manufactured to meet strict AMS 2750 Compliance norms

2. PIT Type Solutionizing Furnaces

The Pit Type Solutionizing Furnaces are preferred for Long components with thicker sections. Designed to quench it vertically to avoid distortion. The design for quench delay typically -30 Seconds.

Temperature Range: 500°C to 600°C

Standard Applications: Solution Annealing/Solutionizing Chamber Design: Cylindrical

Temperature Uniformity: +/-5 °C or Class 2 (+/-6 °C)

Additional Features: Thyristor & PLC based control and SCADA for data acquisition.

These Pit type Furnaces for aluminium can also be designed and manufactured to meet strict AMS 2750 Compliance norms

3. Horizontal Quench Furnace:

The Horizontal Quench furnace is preferred for small Automobile and Aerospace component to process in bulk quantity. Designed to pull the job out and Quench by Pneumatic/hydraulic mechanism with elevated platform in quench tank. This is designed for quench delay of within 15 to 45 Sec.

Temperature Range: 500°C to 600°C

Standard Applications: Solution Annealing/Solutionizing for T6 Process

Chamber Design: Rectangular

Temperature Uniformity: +/-5 °C or Class 2 (+/-6 °C)

Additional Features: Thyristor & PLC based control and SCADA for data acquisition.

These Horizontal Quench furnace can also be designed to meet strict AMS 2750 Compliance norms

Applications of the Solutionizing Process

The solutionizing process is widely used in industries requiring high-performance metal components. Some key applications include:

• Automotive Sector—Critical for engine parts, frames, alloy wheels, gearbox housings, and engine mounts, are made of soft aluminium. Other components, including the car’s chassis, are made of more rigid aluminium alloys which need to be solutionized and precipitation hardened.
• Die Casting Industry- All the house hold and construction component that are made out of Aluminium alloy in Pressure die casting industry.
• Aircraft & Aero space Industries: Light weight material that required in designing the Aircraft and rockets are made out of aluminium which is solutionized and precipitate hardened.
• Aluminium Extrusion Industries: The extrusion industrial furnace manufacturesthe profiles needed to strengthen the profile by solutionizing and ageing.
• Medical Equipment Manufacturing

Medical tools and implants require high-strength stainless steel and titanium. Solutionizing furnaces ensure biocompatibility and durability.

• Construction Industry :

High-performance steels and aluminium used in skyscrapers and bridges undergo solutionizing heat treatment to enhance strength and corrosion resistance.

• This process is often followed by the ageing process, which further enhances the hardness and wear resistance of metals. Solutionizing heat treatment services are essential for automotive, aerospace, medical, and construction industries, ensuring the production of high-quality metal components

Industries rely on solutionizing heat treatment furnaces and aluminium drop-bottom solutionizing furnaces to ensure high-quality metal treatment. This process is often followed by aging heat treatment, further strengthening the metal for industrial applications.

Importance of Solutionizing in Metallurgy

Factors Affecting the Solutionizing Process

To achieve the best results in solutionizing treatment services, several factors must be carefully controlled:

1. Temperature Control

Each metal and alloy has a specific solutionizing temperature range that must be maintained to achieve optimal results. If the temperature is too low, solutionizing furnace suppliers warn that incomplete dissolution occurs, leaving segregated phases. If the temperature is too high, grain growth and oxidation may weaken the material.

For example:

• Aluminium alloys: 450°C – 570°C
• Stainless steel: 1000°C – 1200°C
• Titanium alloys: 800°C – 1000°C

Therelek’s Furnaces ensure that their equipment offers precise temperature controls to prevent overheating and grain boundary weakening.

2. Soaking Time

The holding phase duration is equally important. Metals need sufficient time at high temperatures to allow for complete dissolution of alloying elements. Insufficient soaking time results in incomplete solutionizing, while excessive time can cause grain coarsening.

3. Cooling Rate (Quenching)

Once the metal has been solutionized, it must be rapidly cooled to retain its single-phase structure. The quenching method used in solutionizing heat treatment services can significantly impact the final properties of the metal.

Common quenching methods include:

• Water quenching– Ideal for high-strength aluminium alloys.
• Oil quenching– Used for steels that require controlled cooling.
• Air quenching– Suitable for titanium and certain low-carbon steels.