Someone in the parts world has the stamping equipment making these in steel. Can we just not send some sheets of deep draw aluminum or titanium to him and have a few lightweights made up? About twice the original thickness may work.
I do not know what steel the original part was made of. But, it is most likely was a typical steel with strength about 35,000 to 40,000 psi. The stiffness will be about 30,000,000 psi. TI will get about 60,000 psi strength put only about 15,000,000 psi on stiffness. AL will be at about 10,000,000 psi, but strength can be close to the steel depending on the alloy and treatment.
Got the following from RTI International Metals. Sounds fun. :smash:
George
Forming Titanium
Titanium and its alloys can be cold and hot formed on standard equipment using techniques similar to those of stainless steels. However, titanium possesses certain unique characteristics that affectformability, and these must be considered when undertaking titaniumforming operations.
The room temperature ductility of titanium and its alloys is generally less than that of the common structural metals including stainless steels. This necessitates more generous bend radii and less allowance for stretch formability when cold forming.
Titanium has a relatively low modulus of elasticity, about half that of stainless steel. This results in greater springback during forming and requires compensation either during bending or in post-bend treatment.
Titanium in contact with itself or other metals exhibits a greater tendency to gall than does stainless steel. Thus, sliding contact with tooling surfaces during forming calls for the use of lubricants. Effective lubricants generally include grease, heavy oil and/or waxy types, which may contain graphite or moly disulfide additives for cold forming; and solid film lubricants (graphite, moly disulfide) or glassy coatings for higher temperature forming.
The following is basic information on forming titanium. A great deal of published information exists on titanium forming practices in the common commercial forming processes. The reader is urged to consult the references in the back of this booklet and other qualified sources before undertaking a titanium forming operation for the first time.
Surface Preparation
Before titanium sheet is formed it should be clean and free of surface defects such as nicks, scratches or grinding marks. All scratches deeper than the finish produced by 180-grit emery should be removed by sanding. To prevent edge cracking, burred and sharp edges should be radiused. Surface oxides can lead to cracking during cold forming and should be removed by mechanical or chemical methods.
Plate products should be free of gross stress raisers, very rough, irregular surface finishes, visible oxide scale and brittle alpha case (diffused-in oxygen layers) to achieve reasonable cold or warm formability. Experience has shown that pickled plate often exhibits enhanced formability (e.g., in brake bending and dish forming) compared to plate with as-grit blasted and/or as-ground surface finishes.
Cold Versus Hot Forming
Commercially pure titanium, the ductile, low-alloy alpha and unaged beta titanium alloys can be cold formed within certain limits. The amount of cold forming either in bending or stretching is a function of the tensile elongation of the material. Tensile elongation and bend data for the various grades of titanium sheet and plate can be found in ASTM Specification B265.
Heating titanium increases its formability, reduces springback, and permits maximum deformation with minimum annealing between forming operations. Mild warm forming of most grades of titanium is carried out at 204-316°C (400-600°F) while more severe forming is done at 482-788°C (900-1450°F). Heated forming dies or radiant heaters are occasionally used for low temperature forming while electric furnaces with air atmospheres are the most suitable for heating to higher temperatures. Gas fired furnaces are acceptable if flame impingement is avoided and the atmosphere is slightly oxidizing.
Any hot forming and/or annealing of titanium products in air at temperatures above approximately 590-620°C (1100-1150°F) produces a visible surface oxide scale and diffused-in oxygen layer (alpha case) that may require removal on fatigue- and/or fracture-critical components. Oxide scale removal can be achieved mechanically (i.e., grit-blasting or grinding) or by chemical descale treatment (i.e., molten hot alkaline salt descale). This is generally followed by pickling in HF-HNO3 acid solutions, machining or grinding to ensure total alpha case removal, where required. These acid pickle solutions are typically maintained in the 5:1 to 10:1 volume % HNO3 to HF ratio (as stock acids) to minimize hydrogen pickup depending on alloy type.
Stress Relief and Hot Sizing
Cold forming and straightening operations produce residual stresses in titanium that sometimes require removal for reasons of dimensional stability and restoration of properties.
Stress relieving can also serve as an intermediate heat treatment between stages of cold forming. The temperatures employed lie below the annealing ranges for titanium alloys. They generally fall within 482-649°C (900-1200°F) with times ranging from 30 to 60 minutes depending on the workpiece configuration and degree of stress relief desired.
Hot sizing is often used for correcting springback and inaccuracies in shape and dimensions of preformed parts. The part is suitably fixtured such that controlled pressure is applied to certain areas of the part during heating. This fixtured unit is placed in a furnace and heated at temperatures and times sufficient to cause the metal to creep until it conforms to the desired shape. Creep forming is used in a variety of ways with titanium, often in conjunction with compression forming using heated dies.
Typical Forming Operations
Following are descriptions of several typical forming operations performed on titanium. They are representative of operations in which bending and stretching of titanium occur. The forming can be done cold, warm or hot. The choice is governed by a number of factors among which are workpiece section thickness, the intended degree of bending or stretching, the speed of forming (metal strain rate), and alloy/product type.
Brake Forming
In this operation, bending is employed to form angles, z-sections, channels and circular cross sections including pipe. The tooling consists of unheated dies or heated female and male dies.
Stretch Forming
Stretch forming has been used on titanium sheet primarily to form contoured angles, hat sections, Z-sections and channels, and to form skins to special contours. This type of forming is accomplished by gripping the sheet blank in knurled jaws, loading it until plastic deformation begins, then wrapping the part around a male die. Stretch forming can be done cold using inexpensive tooling or, more often, it is done warm by using heated tooling and preheating the sheet blank by the tooling.
Spinning and Shear-Forming
These cold, warm or hot processes shape titanium sheet or plate metal into seamless hollow parts (e.g., cylinders, cones, hemispheres) using pressure on a rotating workpiece. Spinning produces only minor thickness changes in the sheet, whereas shear-forming involves significant plastic deformation and wall thinning.
Superplastic Forming (SPF)
SPF of titanium alloys is commonly used in aircraft part fabrication, allowing production of complex structural efficient, lightweight and cost-effective component configurations. This high temperature sheet forming process (typically 870-925C°(1660-1700°F)) is often performed simultaneously with diffusion bonding (solid-state joining) in argon gas-pressurized chambers, eliminating the need for welding, brazing, sizing or stress relief in complex parts. Titanium sheet alloys that are commonly superplastically-formed include the Ti-6Al-4V and Ti SP-700 alpha-beta alloys.
Other Forming Processes
Titanium alloy sheet and plate products are often formed cold, warm or hot in gravity hammer and pneumatic drop hammer presses involving progressive deformation with repeated blows in matched dies. Drop hammer forming is best suited to the less high strain rate-sensitive alpha and leaner alpha-beta titanium alloys. Hot closed-die and even isothermal press forging is commonly used to produce near-net shape components from titanium alloys. Trapped-rubber forming of titanium sheet in cold or warm (540°C (1000°F) max.) pressing operations can be less expensive than that utilizing conventional mating "hard die" tooling. Even explosive forming has been successfully employed to form complex titanium alloy sheet/plate components.
The lower strength, more ductile titanium alloys can be roll-formed cold as sheet strip to produce long lengths of shaped products, including welded tubing and pipe. Welded or seamless tubing can be bent cold on conventional mandrel tube benders. Seam-welded unalloyed titanium piping can also be bent cold or warm on standard equipment utilizing internal mandrels to minimize buckling, whereas higher strength alloy seamless piping can be successfully bent in steps via hot induction bending.
Deep Drawing
This is a process involving titanium bending and stretching in which deep recessed parts, often closed cylindrical pieces or flanged hat-sections, are made by pulling a sheet blank over a radius and into a die. During this operation buckling and tensile tearing must be avoided. It is therefore necessary to consider the compressive and tensile yield strengths of the titanium when designing the part and the tooling. The sheet blank is often preheated as is the tooling.
The softer, highly ductile grades of unalloyed titanium are often cold pressed or stamped in sheet strip form to produce heat exchanger plates, anodes or other complex components for industrial service.