Hydroforming｜Technology｜NIPPON STEEL PIPE CO.,LTD.

What is Hydroforming?

Axial compression hydroforming

Hydroforming is a method for processing closed section structures like pipes by applying hydraulic pressure to the inside of the structure.

When compared with the manufacturing of closed section structural parts using metal stamping, this method provides the following advantages and can be expected to result in substantial cost savings and greater strength:

Ability to reduce the number of parts (creation of an integral structure)
No need to weld joints
Reduced tooling costs, since only the outside die is needed for forming
Ability to process complex shapes by applying axial compressive force to the material
Ability to increase strength through work hardening of the material

Types of Processing Methods

There are two major methods of hydroforming: low pressure and high pressure. We can conduct all of the tests on processing methods indicated below with our experimental unit.

		Molding			Comparison of Methods			Equipm-ent cost
		Internal pressure forming	Axial compre- ssion	Press forming	Tube expan- sion rate	Comp-lex shapes	Corner Radius	Equipm-ent cost
Low pres- sure	(in combi- nation with pressing)	○		○	△	△	○	○
Low pres- sure		○			△	△	△	○
High pressure		○	○		◎	○	◎	▲

Hydroforming Experimental Unit

Hydroforming Experimental Unit

（1）Features: Largest size and capacity for a Japanese-built unit

First full-scale processing machine in the steel tube industry
Methods devised to expand process limitations and enable use of the peripheral technologies indicated below.

（2） Equipment Specifications

Mold closing	Method	Hydraulic press
	Mold clamping force	3500T
	Daylight	1600mm
	Stroke	1000mm
	Includes vertical die cushion*
Forming pressure	Normal max.	3000atm
Axial compre- ssion	Method	Dual double acting cylinder*
Axial compre- ssion	Axial compressive force	(100T + 100T) × left and right
Forming dies	Size	MAX1800×1800mm
Forming dies	Moving bolster

* Patented by NSPC

Hydroforming Peripheral Technologies

The following peripheral technologies can be used with the hydroforming experimental unit:

(1) Hydropiercing technology
Operations such as punch piercing and dies piercing can be performed after hydroforming while the tub is still mounted in the equipment.

(2) Sectional double-walled tube processing
A product’s overall weight can be reduced through sectional reinforcing.

(3) Flanging
Flanges can be formed for connecting to other parts.
One-piece molding is possible within the hydroforming machine.

Examples of Intended Uses of Hydroformed Parts