Stress relieving and normalizing, two heat treating processes, can be used to improve the quality and reduce the imperfections in iron and steel parts. Stress relieving heat treatment will reduce, or relieve, the internal stresses of parts after fabrication by heating parts to a temperature below their critical point and cooled slowly. After being welded, formed or cut, stress relieving reduces the chances of parts cracking, warping or distorting during use.
Normalizing is also used to improve parts, but by heating them beyond their critical point and allowing them to cool. This will improve the grain structure of the metal and increase its toughness and strength.
Some commonly relieved and normalized parts include:
Stress Relieved
- Dies
- Gears
- Jigs
- Molds
- Shafts
- Spindles
Normalized
- Axles
- Connecting rods
- Crankshafts
- Fasteners
- Gears
- Pressure vessel components
Ready to get started with INCERTEC’s stress relief or normalizing heat treatment services? Contact us today to request a quote or get more information.
Equipment Used in Stress Relieving Heat Treatment
There are two types of stress relieving: vacuum and air. While both will relieve internal stress they are slightly different in practice. Air stress relieving uses open air to cool the parts after they are heated. This method is cost-effective and fairly efficient. Vacuum stress relieving uses the vacuum furnace to cool the parts after they are heated. The lack of atmosphere helps keep the parts scale-free, so they won’t need to be washed after the process.
Benefits of Stress Relieving Heat Treatment and Normalizing
There are many benefits of both stress relieving and normalizing, let’s break them down here:
Stress Relieving
- Increased fatigue resistance
- Minimized risk of distortion and cracking
- Improved dimensional stability
- Better machinability
- Extended service life
Normalizing
- Improved hardness and strength
- Increased toughness
- Controlled dimensional changes
- Better ductility
- Minimized risk of distortion and cracking
- Extended service life
These processes are well suited for parts that will be used in a wide range of industries, including the automotive, manufacturing and construction industries.
Best Metals for Stress Relieving and Normalizing
The materials that respond the best to both stress relieving and normalizing are iron and all kinds of steels. These materials gain the most from the dimensional stability imparted by these processes.