Unlocking Heat Treatment: How to Make Forgings Stronger, Tougher, and More Reliable

In metal manufacturing, there is a critical process that transforms steel from simply “hard” into “exceptionally strong,” turning ordinary materials into core components capable of withstanding extreme conditions—this process is heat treatment.

What Is Heat Treatment?

Heat treatment is a thermal process involving heating, holding, and cooling metals to improve their physical, chemical, and mechanical properties. If forging shapes the product, heat treatment gives it its soul. It is not only a key step in boosting performance but also essential to extending service life and ensuring safety.

Heat treatment enables forgings to:

● Stronger – improve strength, hardness, and wear resistance

● Tougher – withstand impact and fatigue

● More Stable – reduce residual stress and minimize deformation risk

● More Durable – enhance corrosion resistance for harsh environments

By precisely controlling heating temperature, holding time, and cooling rate, heat treatment reshapes the metal’s microstructure, securing the ideal metallographic structure.

Common Types of Heat Treatment Processes

At Iraeta, we master the full range of mainstream heat treatment techniques and can flexibly combine them to meet customer-specific requirements.

1. Normalizing

The metal is heated above its critical transformation temperature and cooled in air to refine grains and homogenize structure. Normalizing enhances strength, hardness, and toughness, making components more reliable. Commonly used for carbon steels and low- to medium-alloy steels.

2. Annealing

A process of heating and slow cooling that reduces hardness, improves ductility, and enhances machinability—ideal for parts requiring extensive machining.

3. Quenching and Tempering

Quenching rapidly cools steel to achieve high hardness, while tempering reheats it at lower temperatures to relieve stresses and restore toughness. Together, quenching and tempering form the most critical strengthening method, delivering the final performance of the product.

4. Solution Treatment

Widely applied to austenitic and duplex stainless steels, solution treatment involves heating and rapid cooling to dissolve carbides and other phases, enhancing both corrosion resistance and strength.

5. Stress Relieving Annealing

Applied to machined or welded components, this process uses medium to low-temperature holding to release internal stresses and improve dimensional stability.

Beyond these standard processes, we also provide customized solutions such as post-weld heat treatment and stabilization for specialized projects.

Iraeta’s Advantages in Heat Treatment

● Fully Integrated Production Line – From material preparation and forging to heat treatment, machining, and logistics, every step is completed in-house, ensuring higher reliability, complete traceability, tighter quality control, and faster delivery while minimizing outsourcing risks.

● Large-Scale Heat Treatment Capability – With over 80 large furnaces, Iraeta can process forgings up to 22 meters in diameter, meeting the demanding needs of nuclear, hydro, wind, shipbuilding, and energy industries.

● Precision Temperature Control – Our advanced intelligent water quenching pools feature a jet stirring capacity of 7,200 m³/h and a circulation flow of over 2,800 m³/h. Even in summer, high-power chillers maintain water at ~18°C, ensuring consistent cooling performance.

● Strict Process Control – With over 15 years of expertise, our heat treatment engineers design tailored heating and cooling curves for every batch, ensuring hardenability, uniform hardness, and dimensional stability at internationally advanced levels.

Making Forgings Stronger, More Stable, and More Reliable

Only after heat treatment do forgings fully achieve their designed performance, enabling them to withstand high temperatures, extreme pressures, corrosion, and impact in industries such as nuclear power, petrochemicals, and heavy machinery.

At Iraeta, we see heat treatment as the final gateway that elevates forgings from “excellent” to “outstanding.” For project-specific heat treatment solutions, reach out to our engineering team for tailored one-on-one support.