APPLICATION OF CASTED TITANIUM COMPONENTS IN

AUTOMOTIVE EXHAUST SYSTEMS

• Performance benefits of titanium in automotive applications have been

established and widely reported over many years, e.g.:

Titanium in automotive industry

• Applications to automotive industry have been limited to smaller volume

premium, sports and racing cars because of their high cost.

Exhaust systems

Valves, valve springs and retainers

Connecting rods

High strength fasteners

Suspension springs

Turbocharger compressor wheels

Titanium in automotive industry

• Demand for more fuel-efficient and environmentally friendly road vehicles.

• Weight reduction contributes to the

reduction of fuel consumption.

• 1% of weight reduction means 0.7%

reduction of fuel consumption.

• Designers are constantly trying to save weight in their design, and

material choice plays a large part in the design equation.

Titanium in automotive industry

• Cost represents a particular challenge for fundamentally more expensive

materials such as titanium.

technology to manufacture low-cost titanium

alloys

low-cost manufacturing methods for final

titanium products

• Titanium industry has increasingly attempted to meet the tough

financial and life cycle targets set by the automotive industry.

• Attention was concentrated on the development of:

Titanium exhaust systems

• Exhaust systems represent an attractive entry point for titanium into

the automotive industry.

• Use of titanium for those parts is rapidly expanding because its

advantages in weight reduction, processability, freshness and trendiness.

Titanium exhaust systems

• A closer look shows that a car exhaust system is a complex system

where parts are manufactured through various processes:

Cold press

Deep drawing

Bending

Hydroforming

Laser cutting

Machining

Welding

etc.

• We are constantly looking for new technologies that help us speed up

the production process and reduce the manufacturing costs.

Titanium investment casting

Benefits of investment casting

• Production of exhaust components

which have complex design features

and cannot be mass produced using

conventional production methods. Geometrical optimization of components with respect to their functionality

Production cost reduction and conventional production capacities release

• More economical production of certain

components instead of complex

conventional production methods

(laser cutting, machining and welding)

Benefits of investment casting

• Possibility to use recycled titanium

alloys (technological scrap) coming

from other production processes.

Significant product cost reduction

Fast prototyping (wax milling, silica rubber tools, other RP techniques, etc.)

• Possibility to produce prototype

components in development phase

and thus avoiding expensive forming

tools production.

Type of casted exhaust components

• Flanges • Exhaust valves

• Tail pipes • Collectors and adapters

Casting process step by step

• Investment casting of

titanium typically consist of

the following steps:

• An example of step by step

production process of an

exhaust flange:

Casting process step by step

Wax components are injected on a wax injection machine.

Patterns and runner systems are manually assembled in a wax tree.

Casting process step by step

Several ceramic layers are applied in order to form a ceramic shell. When the shell is properly

dry, the wax is extracted and the ceramic is fired.

Pouring in a ceramic shell that is placed on a spinning table in the vacuum melting unit.

Casting process step by step

After the casting process is finished, the ceramic shell is knocked out and casted parts are cut

off from the runner system.

Casted parts are inspected using X-ray radioscopy and controlled by other non-destructive and

destructive methods.

Examples of casted components

• Porsche 911 Turbo and GT2

• Porsche Panamera Turbo

Examples of casted components

• Mercedes Benz C63 AMG

Examples of casted components

• Nissan GTR

Examples of casted components

• BMW Alpina B6

Examples of casted components

• Current challenges:

Collector + exhaust valve Complete exhaust valve

Examples of casted components

CASTED VS. WELDED SOLUTION

Summary

• Several presented examples show us that titanium casting is a

convenient manufacturing process for many exhaust components.

• There are at least two major advantages over conventional methods:

• We are able to cast parts with tailored mechanical properties according

to the requirements using blends of recycled materials.

Speeding up the production process

Reducing manufacturing costs (recycling)