Heat Treatment Process for Metal Casting

Perfect mechanical and physical qualities are necessary to form metals into various shapes. As a result, a metal undergoes some planned production procedures. Heat treatment is one of metal casting technology’s most important manufacturing processes.

Metals are incredibly versatile, as we all know. It can take on a variety of shapes, from significant automobile parts to agricultural components. In contrast, as a metal changes shape, it comes into contact with other particles and alters its mechanical properties. The essential method to preserve its characteristics is heat treatment.

Like other foundries, Dawang steel casting also developed different technologies for the Heat treatment process. This article will describe different heat treating processes used in Dawang Steel Castings. In addition, we will also discuss why it is necessary for metal casting and how it changes the mechanical and physical properties.

What is Heat Treatment? And How Does It Work?

A controlled process of heating and cooling metals is usually called Heat treating. Technically, this controlled heating and cooling of metals doesn’t change the original shape but alters the physical and mechanical properties. As a result, the term heat treating only implies the process of heating and cooling for the initial purpose of changing the metal properties.

heat treatment


As the name implies, heat treatment involves extreme temperatures, often called chilling metals. The heat treatment process strengthens and softens the metals based on specific requirements. The most common technique of heat treatments is annealing, normalizing, quenching, and tempering.

On the other hand, heat treating improves the metal strength and helps in better machining and upgraded formability. Besides, the heat treatment process’s cooling phase restores the metal’s ductility.

Different manufacturing processes sometimes prefer metal heat treatment as the initial production step. The best example can be Dandong Dawang Steel Casting Products.


Dawang Steel Casting Co. Ltd is one of the world’s most popular stainless steel casting companies. We promise our customers all strength specifications based on clients’ requirements. In the case of heat-treating procedures, we keep the latest technology best for stainless steel. Therefore, our customers are always welcome to apply for quotation of any metal properties for their application.

Metal Heat Treating Principle

The basic principle of steel heat treating has three stages: heating, insulation, and cooling. Depending on the client’s requirements, the process parameters are usually changed to maintain quality and cost.

Heating ——> Insulation ——> Cooling

In the heat-treating process, heating is the most energy-consuming step. Radiant heating, induction heating, and salt bath heating are the most common. Dawang steel casting production team selects the specific heating method based on the requirements to ensure fast and uniform heating, controlling and saving costs.

The insulation method implies the holding temperatures method for the austenitization of steel casting. Here austenitization is a steel heat treatment process that helps material strengthen, and this insulation temperature is usually near 20 degrees Celcius.

Heat preservation or insulation is one of the most critical heating treatment methods. At this stage, the operator must maintain the uniform temperature of the casting surface and the core. Besides, he should also keep a consistent structure.

Cooling at different speeds provides different metallographic transformations and specific indicators. An increased cooling rate sometimes provides a perfect structure and restores the grains. As a result, the metal obtains an improved mechanical property.

Importance of Heat Treatment in Steel Casting

All Dawang Steel Casting parts underwent a heat treatment and achieved excellent hardness and maximum durability. Because of its durability, Dawang Steel Casting parts dominate the steel parts market. We are successful because we understand that maintaining product quality is the key to success. And so, from the heat treatment process to the investment casting and sand casting, we keep high-quality production processes.

However, the influence of the heat treatment process dramatically affects the casting parts’ overall quality. Heat treatment improves the metals’ strength, brittleness, and steel toughness. Besides these, there are other remarkable benefits as follows:

  • Heat treatment mitigates stresses and improves machining performance.
  • The process introduces wear-resistant properties.
  • Heat treatment also improves the electrical and magnetic properties of the metal.
  • This process makes Dawang Steel parts tougher and stronger
  • Ultimately increases prolonged lifetime.

Dawang Steel Casting Heat treating processes

Treatment Process for Metal Casting

We have already mentioned that the basic heat treatment process lies between the heating, insulating and cooling stages. However, depending on the temperature holding and cooling time, the types of heat treatment vary.

According to the different treatment procedures, the seven most common heat-treating processes at Dawang Steel Casting are annealing, normalizing, quenching, tempering, solution and age treatment, precipitation treatment for strengthening, and stress relieving.


In the heat-treating process, the metals are heated over the critical or recrystallization point and cooled comparatively at a  slow rate in the heat-treatment furnaces is called annealing. The method usually soaks the steel inside the heat-treating furnaces for a few hours.

Generally, four types of annealing methods depend on the steel composition and requirements. They are complete annealing, spheroidizing, isothermal, and stress-relieving processes. Therefore, an annealing Method upgrades the steel’s strength, flexibility, and stress-relief ability.


Normalizing is almost similar to Heat treatment annealing; the only difference is the cooling method. Where the annealing method is cooling inside the heat treatment furnace, the normalizing process is cooling outside the furnace.

The normalizing method in steel casting foundry heats steel to 30 – 50 degrees Celcius above AC3 and ACM. Here ACM and AC3 are the different temperature critical point for different types of steel.

As a result, the product from the normalizing method gains different properties as they cool down in different environments.


Like other Heat treatment methods,  Quenching also involves heating and cooling the metals in the heat treatment furnaces. However, quenching is relatively more straightforward than other heat treating methods. In this case, the temperature lies between the recrystallization and melting points.

Based on different occasions, Steel quenching treatment uses varieties of quenching media. Air, Oil, water, and brine are the most common media in this heat treatment method.

Dawang Steel Castings specializes in modern technology to perform treatment processes. However, quenching makes the steel harder and more brittle and helps it withstand vibrations and wear. Steels are sensitive to the quenching method, so the operator must carefully handle this method. Therefore, there is almost no possibility of making a mistake.


After the quenching method, the metal usually goes through tempering processes, and tempering usually further heats the metal below the recrystallization point. This method holds the temperature for a few hours. As a result, the metal or steel decreases internal stress and improves flexibility. Usually, all steel casting tools go through this heat treatment method.

In addition, tempering also has three different types, low tempering, medium tempering, and high tempering. Above all, the high heat treating method after quenching is usually popular as quenching and tempering treatment.

Solution and age Treatment

The above four treatment processes are famous for all types of metals. Solution and age treatment usually refer to the treatment of dissolving carbides and other precipitates in the solid solution to get the single-phase structure. Stainless steel and manganese steels are the most common of this method. But the following three heat-treating methods are specialized for stainless steel.

However, the temperature required for stainless steel and manganese steel is 1000 degrees Celcius to 1250 degrees Celcius. The temperature range depends on the carbon contents in the steel structure.

Precipitation Heat treatment for strengthening

Precipitation hardening or PH stainless steels are typical for high tensile strength in the oil, gas, and aerospace industries. Usually, the application requires tensile strength from 850 Mpa to 1700 Mpa and should go through precipitation treatment.

Precipitation treatment adds a specific amount of copper, molybdenum, aluminium, and titanium to achieve the PH or precipitation hardening. Martensitic and austenitic stainless steels are the most common examples of this heat treatment method.

Stress Relieving

As the name suggests, stress-relieving treatment techniques often relieve the stress associated with casting, quenching, and machining. As a result, it helps to stabilize the casting structure. This procedure is typically carried out between 100 and 200 degrees Celsius, below the AC1 critical threshold. The process maintains this temperature briefly before cooling in the heat treatment furnaces.

The most acceptable heat-treating methods for relieving stress are castings made of carbon steel and low- and high-alloy steel.


The heat-treating method is one of the essential steps of both investment and sand casting. Based on the different requirements, Dawang performs specific heat treatment processes. A perfect heat-treating process ensures the steel’s strength, durability, and flexibility. To achieve the treatment process accurately, Dawang keeps the latest technology to fill up every possible solution for their products.

Additionally, Dawang Steel Casting provides its clients with qualified steel casting engineers who can assist you in making the right decision for your company. Any inquiries from our clients are always welcome, and we look forward to providing the most satisfactory answers.