Vol. 4
November Issue
Year 2003

Cover Page

in Vol. 4 - November Issue - Year 2003
Enhancement of Blasting and Peening Processes

Fig. 1: Zirshot Z425 (425-600

Fig. 2

Fig. 3: Available Sizes

Fig. 4: Bottle mould cleaning in a wheel turbine machine

Fig. 5: Aluminium cast mould cleaning

Fig. 6: Stainless steel finishing

Fig. 7: Surface preparation in a free blasting room

Fig. 8

Air Blasting Machine at Test Facility in Le Pontet

Ceramic beads from Saint-Gobain ZirPro: Thoughtful engineering brings practical and cost effective solutions

Zirblast and Zirshot Ceramic Beads: Process Improvement Tools

With its extensive knowledge of ceramic manufacturing, Saint-Gobain ZirPro answered the need for high performance beads, grains and powders, by offering two innovative products: Zirblast ceramic beads for blasting, and Zirshot for high performance in peening applications (Fig. 1).

The use of Zirshot started twenty years ago in the USA for shot peening of aircraft structures and jet engine parts. Shortly thereafter, Europe started using Zirshot, extending its applications to the automotive and mechanical industries.

The first industrial use of Zirblast was for mould cleaning in the glass container and tire industries, and eventually its use was extended to surface preparation applications for stainless steel fabrications in food, chemical, petrochemical and nuclear industries.

High Performance in Industrial Use

Zirblast and Zirshot were designed to provide…:
- Chemical inertness
- High mechanical strength: wear and impact resistance results in no dust
- High level of hardness
- Good elastic behaviour, providing high transmission of impact energy

…and to be adaptable to multiple technologies:
These unique beads can be used either in wheel turbine or compressed air devices. They find application in the treatment of many materials such as light alloys, stainless steel, high strength steel, non ferrous alloys, plastics, ceramics, hard coatings, wood, stone, etc.

The working load is easily cleaned without needless bead losses, just by using a cyclone or air wash separator. This is possible because Zirblast simultaneously:
- Has ideal density and roundness
- Doesn’t disintegrate into dust
- Doesn’t wear excessively

An Ervin test graph (fig 4) shows a lifetime plot of Zirblast, in the same range as cast steel shot.

Available sizes (mm) (see table)

Current Blasting Applications

Tool Cleaning (Fig. 5 and Fig. 6)
Zirblast provides highly efficient cleaning without damaging tools:
- Thin section parts remain intact
- Edges stay sharp
- Roughness level does not increase
- Polishing operation after cleaning is reduced or no longer needed.

Main applications in tool cleaning are:
- Tire and glass bottle moulds
- Extrusion or injection dies (aluminium, light alloys and plastics)
- Material handling tools for painting, coating, metallization, brazing, welding, etc.

A Cost Saving Solution:

Thanks to its high efficiency and tool care capacity, in high production environments (ie automotive industries), Zirblast offers the possibility to insert an in-line tool cleaning operation. In this manner tools are cleaned as often as needed without damaging them.

Surface Preparation and Finishing

Zirblast allows highly efficient and very fine surface preparation and finishing of light alloys, stainless steels, non-ferrous alloys, natural materials, plastics:
- Low roughness level (Ra 0.37 microns)
- No iron contamination
- Satin finish
- Excellent cleaning ability
- Consistent and reproducible results

Main applications in surface preparation and finishing are:
- Finishing stainless steel for equipment used in food, pharmaceutical, chemical, petrochemical and nuclear industries (Fig. 7)
- Final finishing or preparation of aluminium castings and profiles prior to coating
- Special effects on stainless steel, aluminium, stones or wood for architectural applications
- Surface preparation of automotive or architectural applications parts prior to anticorrosion coating
- De-burring of high precision parts after heat treatment or sintering processes

Although not aggressive (in terms of surface removal), Zirblast can be efficient and cost effective for surface preparation prior to coating or paint stripping.
- preparation of aluminium cookware prior to PTFE coating
- surface preparation prior to painting or stripping of automotive wheels

These lists can be completed by numerous other applications or examples. We can study, with potential users, any specific request, propose the suitable product in terms of size distribution and even propose adjustment of the working conditions.

High Performance Applications: Shot Peening

Due to its high mechanical properties, Zirshot significantly improves the behavior of materials subject to fatigue, corrosion, pitting, galling or a number of these in combination.

The Zirshot working model is:
- Under low impact energy: work hardening, resulting in an exceptionally smooth surface, very high level of compressive stress at the surface and almost no Hertzian pressure below the surface

- Under high impact energy: both work hardening and Hertzian pressure effect take place but the surface remains smooth, while a high level of compressive stress is achieved at the surface along with good depth compression below the surface

Zirshot main applications in shot peening:
- Fan blades and compressor blades of jet engines and industrial turbines
- Aluminium and titanium structures of commercial and military aircrafts, including wheels and brakes.
- Peen forming and peen straightening of aircraft structures and wings
- Gears for automotive transmissions, with high performance in fatigue and pitting strength improvement.
- Springs for automotive valves, clutches, suspensions
- Anti-galling of threads in oil drilling equipment and gas exploration
- Medical implants

Test Facility in Le Pontet

At this workshop, Saint-Gobain ZirPro can offer an extensive range of services to current or potential customers. The equipment is designed to simulate industrial conditions as closely as possible. It includes a wheel blast machine, an air blast machine as well as a gravity-feed suction blasting equipment. Furthermore there is access to a surface and media inspection microscope and profilometer. The showroom is also equipped to treat pre-production parts, to define the operating conditions for the ceramic beads and determine the adjustments that will optimise production costs. Saint-Gobain ZirPro also offers training and expertise services to customers and partners.

Current or potential users of Zirblast and Zirshot ceramic beads may contact the sales representative who initiates the test program and accompanies the customer until industrial implementation.
The customer may send a representative to attend the testing program and thus acquire all information and data needed for the use of ceramic beads in his application. The tests can also be conducted according to a program defined jointly with the customer, followed up by the issuance of a test report and recommendations for use.

Author: François-Xavier Abadie and Gustavo Fernandez
Authors: François-Xavier Abadie
Product Manager - Surface Treatment
Gustavo Fernandez
Sales Manager North America
SEPR - Saint-Gobain ZirPro
Tel.: +33 4 90 39 99 14, Fax: +33 4 90 39 99 98
E-Mail: zirpro@saint-gobain.com