Precision Flow forming

Precision Flow forming is capable of dimensional accuracy well beyond other forming methods. Since flow-forming tooling is subject to little or no wear, the CNC-controlled process offers consistent and repeatable accuracy from part to part and lot to lot.

Precision

The all-around dimensional controls for diameters and walls offered by precision flow forming will reduce or eliminate your need for secondary turning, grinding, and honing operations. The high degree of roundness, straightness, and concentricity achievable by our flow-forming process will often reduce or eliminate the necessity for straightening and balancing your finished component. The very fine surface finishes generated by flow forming on the inner and outer diameters will, in most cases, also void your requirement for honing and/or polishing.

Thin walls

Precision flow forming can generate economically and without difficulty very thin and precise wall thicknesses, regardless of the diameter size of the component. If you have had to contend with the difficulties and costs of managing the deflection of a thin metal body under turning or grinding operations, you will come to greatly appreciate our precision flow-forming process.

Varied Walls

Unlike any other type of forming process (i.e., extruding, forging, impact extruding, deep drawing, pilgering, drawing over mandrel, etc.), flow forming can vary the wall thickness of a component at any place and as many times as desired along the length of the flow formed component without additional cost.

Hardened Metals

Flow forming offers the unique possibility of forming to size a pre-hardened workpiece, thus eliminating the difficulties and high costs associated with the final machining, grinding, and honing of a hardened and distorted hollow component. Our precision flow-forming method of manufacturing allows us to achieve high dimensional accuracy and, at the same time, guarantee conformance to your required mechanical properties right off the flow-forming machine.

Grain Structure

As a result of the cold work (strain hardening) that occurs during the process cycle, a flow-formed component will have considerably higher mechanical properties than the ones of the starting material. Typically, the preform material is plastically deformed with wall reductions in excess of 75% of the starting wall thickness, causing a substantial refinement of the grain structure and a total realignment of the grains’ microstructure in a very uniform, axial direction. The greater the wall reduction, the finer the grain’s microstructure in the finished component. If necessary, the grain structure can be recrystallized by a post-forming annealing cycle.

Crystallographic Texture

During the flow-forming cycle, all the crystals that form the starting grain structure will be displaced and realigned. The overall orientation of these crystals is known as ”texture.” Nearly all mechanical properties are influenced by the metal’s texture. In a flow-formed component, the overall texture is always uniformly oriented. For example, in the case of Hexagonal Closed Packed (HCP) materials such as Titanium and Zirconium, their flow-formed crystals will have radially oriented basal planes. This condition increases the biaxial strength of the metal, effectively increasing the circumferential strength. The flow-formed crystallographic texture can be further intensified by a post-flow-forming annealing cycle. On a micro level, the annealing will recrystallize the grain structure, while on an atomic level, the texturing effect will be magnified.

Metal Properties

Flow forming is a cold working process which, through the strain hardening of the base metal, substantially increases the yield and tensile strengths of the formed material. Certain customers choose to take advantage of the improvement in mechanical properties by effectively designing thinner walls for lighter components. Others prefer post-forming stress-relieving or solution annealing of the flow-formed component to remove residual stresses. In other cases, the flow-formed component will be heat-treated or aged to alter the levels of achieved strength, hardness, and ductility to meet specification requirements.

Seamless

One major benefit offered by flow forming is its seamless construction. Quite often, we are also able to integrate more than one previously separate component into the same seamless flow-forming structure.

Savings

A seamless component will eliminate manufacturing problems associated with welding, such as heat-affected zones, part distortion, weld porosity, and failures, as well as the inherent costs of the weld, its radiography, and general testing. Elimination of all the above should be factored into the cost savings when comparing the utilization of a seamless flow-formed component.

Precision Flow forming is a chipless, cold-forming process capable of forming high-strength and hard-to-form metals to the desired geometry with tight dimensional controls throughout. With the ever-increasing cost of metal, many customers have come to greatly appreciate our ability to flow form to net shape.

No Waste

We start with a short, thick preform and typically flow form it four to six times its starting length. Material waste and labour costs are minimal. If your program is burdened by the costs and waste associated with gun drilling/trepanning of solids, and/or the machining of extrusions, you are a good candidate for flow forming.

Net Shape

In almost all cases, we can flow-form to net shape, maximizing material utilization while eliminating post-forming machining.

Seamless

Our process is seamless. At times, we can also integrate more than one of your components into the same flow-formed component. The cost of welding, related problems, and necessary testing are all eliminated.

Hardened Metals

With flow forming, we can form your component from pre-hardened metal to your specified mechanical properties. If this approach is feasible for your part, you will eliminate the high costs of finish-machining and/or grinding a most likely heat-distorted component to its final accuracy.

Flanges

We can eliminate your costs of manufacturing, circumferential welding, and related testing of end flanges or stub ends by integrating them as part of the seamless flow-formed component.