As a form of industrial-grade metal, hot work tool steel is a generic term for different types of thermal procedures used on various materials. The processes that the engineers use would modify or enhance the metal properties. This happens by changing the atomic structure of the metal. This helps to meet the specific needs of the application that you intend to apply for. Heat treatment is also helpful in changing the initial, intermediate, and final properties of the metal.
Changes that Heat Treatment Brings in
The different types of procedures can:
- Soften plastic or metal (through annealing).
- Harden the metal (through case hardening, nitriding and carburizing).
- Harden or soften just one part of the metal (through the application of flame or through induction.
- Homogenize the moulded parts of plastic injection (through annealing).
- Reduce stress from the components, either before or post-machining, or also from extruded, formed, bent or cut material (through stress relief).
- Alter magnetic permeability (through magnetic anneal and metal anneal).
Procedures of Heat Treatment Processes
The most common procedures of heat treatment for hot work steel include:
- Preheating: It refers to heating up to 500-800°F or 260-427°C for the reduction of thermal shock.
- Austenitizing: It refers to heating up to a temperature as high as 1500-1900°F or 816-1038°C and forming austenite.
- Quenching: It means fast cooling to form martensite.
- Tempering: It refers to heating up to 300-600°F or 149-316°C to lessen the chance of brittleness.
How Heat Treatment Affects Hot Work Steel
Heat treatment would impact various properties of hot work tool steel. This influences its hardness, microstructure, toughness, and resistance to thermal fatigue, strength and wear. So with heat treatment:
- Hardness increases through the formation of martensite.
- Microstructure alters, which adds strength to the steel and also makes it harder.
- Toughness increases, which makes the metal less brittle.
- Resistance to thermal fatigue increases its resistance to thermal shock.
- Strength can increase by up to 50% with proper heat treatment.
- Wear resistance improves due to the increase in hardness.
Specific Effect on Different Types of Hot Work Steel
LeadingHot Work Tool steel suppliers like TGKSSL direct that different types of hot work metal require different types of heat treatment for optimal performance. For example:
- The H13 tool steel variety requires austenitizing at a temperature as high as 1850°F or 1010°C for about 30 minutes. It is possible to quench it in both water and oil. The steel also needs to be quenched at 500°F or 260°C for about 2 hours.
- The S-7 variety of tool steel austenitizes at a temperature of around 1800°F or 982°C for 30 minutes. It is also possible to quench them in both water and oil. The optimal tempering temperature is about 400°F or 204°C for 2 hours.
Common Errors in Heat Treatment Errors
A faulty or improper heat treatment often happens owing to:
- Incorrect rate of quenching.
- Insufficient austenitizing.
- Burning or overheating.
- Insufficient tempering.
What can go wrong?
Improper heat treatment can result in:
- Lesser tool life.
- More maintenance cost.
- Impaired performance.
- Tool failure.
How to optimize Heat Treatment?
To make the most of your heat treatment experience, it is important that your mechanic:
- Consider tool application and design.
- Conduct microstructure and hardness testing.
- Maintain quenching rate and temperature.
- Discuss the specifications of materials with your service provider.
Trust your Partner
Companies like TGKSSL have been in the industry for many decades. These organizations house metallurgists, technicians, and equipment operators for maximum quality control. They can also customize their metals in the way you need for your applications.