The leaf spring is one of the oldest part in a vehicle which has been used since the medieval age. It's used until 1970's on the automobiles but nowadays It's used only on commercial vehicles. Pickups,Jeeps,Minibuses,Buses,Trailers and Trucks are the vehicles where leaf springs are used for suspension
There are mainly 3 types of leaf springs as traditional , parabolic and air linkers (Z type ) depending to the thickness of the leaf springs. There are also mainly 3 grades of spring steel as 55Cr3 , 50CrV4 and 51CrMoV4
The process of leaf spring is as follows :
1. Cutting the spring steel
2. Center hole punching / Drilling
3. End Heating process forming (hot & cold process)
1. Eye Forming / Wrapper Forming
2. Diamond cutting / end trimming / width cutting / end tapering
3. End punching / end grooving / end bending / end forging / eye grinding / end rolling
4. Center hole punching / Drilling / nibbing
4. Heat Treatment
1. Heating
2. Hardening
3. Cambering
4. Quenching
5. Tempering

5. Surface preparation 1. Shot peening / stress peening
2. Primary painting
6. Eye bush preparation process
1. Eye reaming / eye boring
2. Bush insertion
3. Bush reaming

7. Assemble 1. Presetting & load testing
2. Finish painting
3. Marking & packing


Three basic types of bends are used on U-bolts depending on the suspension design and the shape of the mating parts: Round Bend, Semi- Round Bend and Square Bend. Additionally, each of these types of bends may used forged material. This is used primarily where additional clearance is required between the U-bolts and, for example, the frame. How to measure a U-bolt: Regardless of the bend type, all U-bolts are measured in the same manner as show here. The U-bolt size is given as Diameter (A) x Distance Between Legs (B) x Leg Length (C). Additionally the bend type must also be specified; either round, semi-round or square. Forged top U-bolts are best ordered application and leg length since the type of forging is usually unique to the particular application and must be maintained to provide proper fit and clearance.


There are mainly 2 types of bushings as metal and rubber The bushing is used on the assembly process of the leaf springs its the part where leaf spring is attached to the chassis