In steel manufacturing industries, there are various varieties of steels and alloys are used. The use of a particular type of steel depends on the equipment to be made from it. From the various varieties, hot work steel and cold work steel are the popular ones for manufacturing various steel equipment. How does hot work steel differ from cold work steel? Hot work steel is superior to cold work tool steel primarily in high-temperature applications. It offers superior heat checking resistance, hot strength and thermal fatigue resistance. Hot work steel maintains its hardness even at high temperature applications. This makes it a better choice for forging, die casting and extrusion while providing superior toughness and shock resistance. Let’s discuss in detail how hot work steel is better than brittle cold work steel options in this blog.
Key Advantages of Hot work steel Over Cold work tool steel:
- Heat resistance: High temperature performance refers to a material’s ability to maintain strength and functionality while being exposed to intense heat. Hot work steel, because of its high temperature bearing capacity, is extremely heat-resistant. This type of steel maintains its hardness even at high temperatures, which makes it suitable for manufacturing various equipment. It is suitable for various industrial applications performed at different temperatures, while cold-worked steel softens and is not suitable at high temperatures.
- Thermal fatigue resistance: Resistance to thermal fatigue is a material’s bearing capacity to repeated, rapid or extreme temperature changes without developing any cracks or deformation to the metal. Hot work steels like H13 have high temperature yield strength because of their thermal fatigue resistance. This steel type has high hot-yield strength and resistance to softening at increased temperature, and performs best for enhancing thermal fatigue resistance. The hot work steel has high tempering resistance, which is crucial to prevent strength loss during repeated heating cycles.
- Extreme toughness and ductility: Hot work steel is specially designed to have an extreme level of toughness and adaptability at high working temperatures. These two are the important properties for measuring a material’s behaviour under extreme stress. These properties measure resistance to damage under high load and determine how much a material can stretch or deform without any damage. It is an essential requirement for processes like forging and casting in manufacturing industries. It has lower carbon content compared to cold work steels, which makes hot work steel offer greater toughness and resistance to cracking under high impact load.
- Thermal shock resistance: Hot work steel provides outstanding thermal shock resistance, which is important for surviving rapid changes between heating and cooling processes. It is the capability of the metal to bear sudden temperature changes, which helps in preventing premature cracking and failure due to thermal fatigue. The key materials that have high thermal shock resistance in hot work steel include AISI H13 and similar grades, which are designed to maintain hardness while resisting heat checking.
- Reduced Internal Stress: To reduce or remove the internal stress created in the metal, the technique used for this is called the stress-relieving technique. These stresses can be caused in different ways, ranging from cold working to non-uniform cooling. Stress relieving is usually trained by heating a metal below the lower critical temperature and then cooling evenly. The cold-worked materials can have internal stresses from shaping at room temperatures, but hot-worked steel is processed at higher temperatures, which often reduces internal stresses.
Conclusion
In conclusion, hot work steel is the perfect choice for high temperature and high impact environments like forging, extrusion and die casting. In this steel type, the tools must withstand the heat exceeding three hundred degrees Celsius without softening. In contrast, cold work steel offers good precision and hardness at room temperature, but it is not suitable for hot repetitive applications. Because the cold steel will lose its strength and crack at high temperatures, leading to premature failure. Therefore, Bk Steel Company specially uses hot work steel for manufacturing various applications, which is designed to handle thermal fatigue. We make sure that our steel products are made smoothly without any premature failure under the guidance of our expert, Mr. Manish Maddan.
FAQs
- Why does hot-worked steel not crack under high stress?
This is because it has the ability of high toughness and ductility. It helps to prevent brittle failure during heavy-duty and high-temperature operations.
- Can I use cold-work steel for hot forging?
No, cold-worked steel will lose its hardness. It will become soft and fail prematurely due to poor high-temperature strength and thermal shock resistance.
